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Made available in DSpace on 2022-04-28T19:40:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 In the Ediacaran marine succession of the Cerro Negro Formation (Tandilia System, NE Argentina), abundant microbially induced sedimentary structures indicate general conditions of substrate biostabilization. Numerous discoidal structures in this succession were previously interpreted as moulds of soft-tissue holdfasts of sessile organisms, within the form genus Aspidella. In this study, we performed a detailed re-analysis of some of these features and discuss two alternative hypotheses to explain their genesis: (1) as the result of soft-sediment deformation and fluid injection structures; and (2) as structures of active animal-sediment interaction (i.e. trace fossils). We show that the dome-shaped discs are internally laminated, with a cylindrical to a funnel-shaped vertical tube at their central region. The presence of these downwards vertical extensions and other intricate internal arrangements cannot be explained under the taphonomic spectrum of discoidal fossils, but shows striking similarities to Intrites-like structures and other sand-volcano-like pseudofossils (e.g. Astropolithon). However, some structures are hard to distinguish from vertical dwelling burrows with funnel-shaped apertures and thick-lined walls, commonly produced by suspension- and detritus-feeding invertebrates (e.g. Skolithos isp., Monocraterion isp. and, less likely, Rosselia isp.). Since reliable age constraints are unavailable, and further investigation concerning other palaeobiological indicators is needed, the most parsimonious hypothesis is that of a structure derived from fluid-escape processes. Our study demonstrates the importance of detailed investigation on discoidal structures in either upper Ediacaran or lower Cambrian strata. Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Avenida 24A, 1515 Departamento de Ecologia e Biologia Evolutiva Universidade Federal de São Paulo, Rua Prof. Artur Riedel, 275, Jd. Eldorado Geology Graduate Program Unisinos University, Av. Unisinos, 950 Instituto de Hidrología de Llanuras dr. E. J. Usunoff, República de Italia 780 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista Centro de Investigaciones Geológicas UNLP-CONICET, calle 1, n. 644 Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Avenida 24A, 1515 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista

Made available in DSpace on 2022-04-28T19:47:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Global Neoproterozoic glaciations are related to extreme environmental changes and the reprise of iron formation in the rock record. However, the lack of narrow age constraints on Cryogenian successions bearing iron-formation deposits prevents correlation and understanding of these deposits on a global scale. Our new multiproxy data reveal a long Cryogenian record for the Jacadigo Group (Urucum District, Brazil) spanning the Sturtian and Marinoan ice ages. Deposition of the basal sequence of the Urucum Formation was influenced by Sturtian continental glaciation and was followed by a transgressive interglacial record of >600 m of carbonates that terminates in a glacioeustatic unconformity. Overlying this, there are up to 500 m of shale and sandstone interpreted as coeval to global Marinoan glacial advance. Glacial outwash delta deposits at the top of the formation correlate with diamictite-filled pa-leovalleys and are covered by massive Fe and Mn deposits of the Santa Cruz Formation and local carbonate. This second transgression is related to Marinoan deglaciation. Detrital zircon provenance supports glaciostatic control on Cryogenian sedimentary yield at the margins of the Amazon craton. These findings reveal the sedimentary response to two marked events of glacioeustatic incision and transgression, culminating in massive banded iron deposition during the Marinoan cryochron. Faculdade de Tecnologia Universidade de Campinas Departamento de Geología Universidade Federal de Ouro Preto Instituto de Geociências Instituto de Astronomía Geofísica e Ciências Atmosféricas Universidade de São Paulo Departamento de Geologia Universidade Estadual Paulista Departamento de Geologia Universidade Estadual Paulista

Made available in DSpace on 2022-04-28T19:45:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Instituto Serrapilheira We combine U–Pb in-situ carbonate dating, elemental and isotope constraints to calibrate the synergy of integrated mountain-basin evolution in western Gondwana. We show that deposition of the Bambuí Group coincides with closure of the Goiás-Pharusian (630–600 Ma) and Adamastor (585–530 Ma) oceans. Metazoans thrived for a brief moment of balanced redox and nutrient conditions. This was followed, however, by closure of the Clymene ocean (540–500 Ma), eventually landlocking the basin. This hindered seawater renewal and led to uncontrolled nutrient input, shallowing of the redoxcline and anoxic incursions, fueling positive productivity feedbacks and preventing the development of typical Ediacaran–Cambrian ecosystems. Thus, mountains provide the conditions, such as oxygen and nutrients, but may also preclude life development if basins become too restricted, characterizing a Goldilocks or optimal level effect. During the late Neoproterozoic-Cambrian fan-like transition from Rodinia to Gondwana, the newborn marginal basins of Laurentia, Baltica and Siberia remained open to the global sea, while intracontinental basins of Gondwana became progressively landlocked. The extent to which basin restriction might have affected the global carbon cycle and climate, e.g. through the input of gases such as methane that could eventually have collaborated to an early Cambrian greenhouse world, needs to be further considered. CPMTC Research Center Universidade Federal de Minas Gerais Departamento de Geologia Universidade Federal de Ouro Preto Department of Geoscience and Natural Resource Management University of Copenhagen, Øster Voldgade 10 NEG-LABISE Universidade Federal de Pernambuco Laboratório de Estudos Geodinâmicos Geocronológicos E Ambientais Universidade de Brasília Department of Geology São Paulo State University Geological Survey of Brazil – CPRM Department of Geology São Paulo State University FAPESP: 2018/26230-6 CNPq: 303566/2019-1 FAPEMIG: PPM-00618-18 Instituto Serrapilheira: Serra-1912-31510

The Aptian Crato Konservat-Lagerstätte is renowned for its exceptionally preserved fossils in lacustrine laminated limestones. Although previous works on this site include numerous taxonomic studies, its taphonomy remains a subject of debate. Herein, we present new data on the taphonomy of decapod crustaceans preserved in wrinkle laminites, highlighting the role of microbial mats in enhancing fossil preservation. Our results suggest that benthic microorganisms may have promoted protection and organic mineralization of some of the allochthonous to parautochthonous organic remains within the microbial laminites of the Crato lake. Overall, this work provides the first empirical evidence that the preservational pathways of the fossils in the Crato Konservat-Lagerstätte involved microbial mats.

Made available in DSpace on 2019-10-04T12:40:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The Aptian Romualdo Formation is a siliciclastic-dominated sedimentary unit recording the last marine ingression within the Cretaceous interior basins of northeastern Brazil. At the western margin of the Araripe Basin, rocks of the Romualdo Formation are mainly represented by carbonates resting abruptly over the Proterozoic crystalline basement. Detailed mapping and stratigraphic analysis revealed two stromatolite fields that were described and discussed for the first time. Several bioherms, biostromes and isolated stromatolites characterized by distinct microbialite morphologies associated with echinoid-rich strata have been identified, suggesting that hypersalinity, water depth and hydraulic conditions were the main factors controlling stromatolite morphogenesis. A cm-thick amalgamated bivalve rudstone, resting directly on the basement and representing a shell concentration formed above the fair-weather wave base was also recorded. Based on the regional distribution of the stromatolite types and associated sedimentary fades, we interpret the depositional environment as a local low gradient carbonate ramp deepening to the east. Our data robustly indicated that the western rocky shorelines of the Araripe Basin during the Aptian were populated by microbial mats and stromatolites in a condition analogous to the modern world-famous Hamelin Pool, Shark Bay, Western Australia. Finally, the development of stromatolites and echinoid-bearing microbialites at the western margin of the basin may be correlated with the formation of bakevelliid- and cassiopid-rich shell beds in the upper part of the Romualdo Formation at the eastern margin. (C) 2019 Elsevier B.V. All rights reserved. Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-12506900 Rio Claro, Brazil Friedrich Alexander Univ Erlangen Nurnberg, FG Palaoumwelt, GeoZentrum Nordbayern, Loewenichstr 28, D-91054 Erlangen, Germany Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil Univ Reg Cariri, Dept Ciencias Biol, Campus Pimenta 1161, BR-63100000 Crato, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-12506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil FAPESP: 2016/13214-7 FAPESP: 2017/20803-1 FAPESP: 18/01750-7 Petrobras: 2014/00519-9 CNPq: 444070/2013-1 CNPq: 401039/2013-5 CNPq: 1082 30017/2015-3 CNPq: 152385/2016-9 CNPq: 301294/2018-6

Made available in DSpace on 2019-10-04T12:35:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) PROPE - UNESP The Itapucumi Group is recognized worldwide due to its well-preserved Ediacaran fossil assemblage. Despite its paleontological importance, this unit remains as the least studied South American Neoproterozoic sedimentary succession. Recorded at northern Paraguay, the Itapucumi Group is a similar to 400 m-thick siliciclastic and carbonate succession deposited on the Paleoproterozoic basement of the Rio Apa Craton. At west, this unit is deformed and metamorphosed, whereas the eastern domain constitutes an undeformed cratonic cover. The Itapucumi Group comprises, from base to top, siliciclastic rocks of the Vallemi Formation, succeeded by limestones and dolomites of the Camba Jhopo and Tagatiya Guazu formations, which are capped by marls and mudstones of the Cerro Curuzu Formation. The entire sedimentary succession consists of three depositional sequences deposited in a large rimmed carbonate platform open to the ocean westward: S.1, the lowermost predominantly terrigenous, and sequences S.2 and S.3, comprising carbonate and terrigenous facies associations. Carbon isotope data from limestones and dolostones show values of + 1.93 parts per thousand delta C-13 VPDB and Sr-87/Sr-86 ratios of 0.7084 and 0.7089, in agreement with a depositional age between 600 Ma and 550 Ma and coherent with the Cloudina biozone. These data support the paleogeographic correlation between the Itapucumi and Corumba groups at the margins of the Amazonian and Rio Apa Craton. The siliciclastic basal successions of both units, are interpreted as deposited in rift basins developed during the fragmentation of the Rodinia supercontinent (Cryogenian to Ediacaran). Later thermal subsidence led to the generation of a new accommodation space around 550 and 528 Ma, recording extensive carbonate platforms along the margins of Pampia, Amazonian and Rio Apa cratons. The deformation of the Itapucumi and Corumba basins started at around 528 Ma, and was controlled by the reactivation of listric and normal faults generated during the rift stage. The opposite tectonic vergence observed in the Vallemi and Paraguay fold-and-thrust belts can be ascribed to oppose master fault polarities in the precursor basins of this context, as well as to the rigid behavior of the Rio Apa Craton. The compressional phase ended around 484 Ma, and corresponding to the last stresses related to the Brasiliano Cycle and the closure of SW Gondwana. Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Campinas UNICAMP, Fac Tecnol, Rua Paschoal Marmo 1888, BR-13484332 Jd Nova Itdlia, Limeira, Brazil Univ Sao Paulo, Inst Energia & Ambiente, Ave Prof Luciano Gualberto 1289, BR-05508010 Sao Paulo, Brazil Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508010 Sao Paulo, Brazil Univ Fed Sao Paulo, Dept Ecol & Biol Evolut, Rua Prof Artur Riedel 275, BR-09972270 Diadema, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil Univ Brasilia, Inst Geociencias, ICC Ala Cent, BR-70910900 Brasilia, DF, Brazil Fac Ciencias, Dept Geol, Calle Igua 4225, Montevideo 11400, Uruguay UNLP, CONICET, Ctr Invest Geol, Calle 1,644, RA-1900 La Plata, Buenos Aires, Argentina Univ Fed Pernambuco, NEG LABISE, Ave Acad Helio Ramos, BR-50670000 Recife, PE, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil FAPESP: 2004/012330 FAPESP: 2010/19584-4 FAPESP: 2010/02677-0 FAPESP: 2015/24608-3 CNPq: 490234/2005-4 CNPq: 444070/2014-1

Made available in DSpace on 2021-06-25T12:40:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras The Aptian evaporitic transitional sequence (sag phase) of the Brazilian marginal basins records the first connection between the Central and South Atlantic oceans in the equatorial area. During this phase, lacustrine carbonate reservoirs and giant salt deposits developed in the southern basins of Santos and Campos, forming world-class petroleum reservoirs. The sag succession is also well-preserved in the interior rift basins of north-eastern Brazil, where upper Aptian strata are represented by a continuous section. This contribution presents an interpretation of the evolution of a third-order depositional sequence comprising lacustrine limestones, marine siliciclastic facies and evaporite deposits of the intracontinental Araripe Basin. The Lowstand Systems Tract is characterized by fluvial deposits filling accommodation generated during the syn-rift phase. The overlying deposits comprise marine facies with preservation of dinoflagellates and marine ichnotaxa, evidencing marine deposition in bayhead delta settings. The transgressive surface is represented by limestones, including the Konservat-Lagerstatte laminites, onlapping the basement rocks. Above, tide-dominated bay deposits with distinct subtidal, intertidal and supratidal portions are recorded. The Maximum Flooding Surface is a dark shale below foreshore to shoreface facies, marking the beginning of the Highstand Systems Tract, culminating with deposition of evaporites (gypsum and anhydrite). The stratigraphic architecture and palaeocurrents measured in different facies associations suggest that marine waters reached the basin from the south. The data unequivocally records late Aptian marine ingressions of an incipient South Atlantic Ocean over the interior basins of north-eastern Brazil, while lacustrine conditions were still prevailing in the Pre-Salt sag units of the Santos and Campos basins. Univ Fed Parana, Inst LAMIR, Dept Geol, Av Cel Francisco H Santos 100, BR-81531980 Curitiba, PR, Brazil Univ Fed Ouro Preto, Escola Minas, Dept Geol, BR-35400000 Ouro Preto, MG, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol, Ave 24-A,Bela Vista 178, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Distrito Rubiao Jr S-N 510, BR-18618970 Botucatu, SP, Brazil Univ Saskatchewan, Dept Geol Sci, Saskatoon, SK S7N 5E2, Canada Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol, Ave 24-A,Bela Vista 178, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Distrito Rubiao Jr S-N 510, BR-18618970 Botucatu, SP, Brazil FAPESP: 2016/13214-7 CNPq: 401039/2014-5 Petrobras: 2014/00519-9

Made available in DSpace on 2022-05-01T12:56:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The influence of microbial communities upon sedimentary dynamics is an issue of increasing significance. Over the last decades, studies have revealed a particular class of sedimentary structures and textures produced by the interaction among distinct flows, marine substrate, and benthic microbial communities. We present evidence of the oldest record of microbially-induced sedimentary structures (MISS) in South America, as recorded in low-grade metasedimentary rocks of the Early Mesoproterozoic (~1536 ± 33 Ma) Tiradentes Formation, state of Minas Gerais, SW Brazil. Types 1, 2, and 3 correspond to wrinkle, pustular, and dome structures related to flat or rippled bed surfaces, preserved in metasandstone deposited in shallow marine settings. Evidence supporting the microbial origin of these structures includes delicate morphology, degree of alignment, presence of original mat cover, and orientation of quartz grains indicating biostabilization. The presence of distinct MISS associated with well-preserved ripple marks, wrinkled surfaces, and flatbeds suggests deposition under varied energy conditions with different potentials for the preservation of surficial structures. Vertical growth of microbial communities influences sediment cohesion and stability. This reduces substrate roughness and, as a consequence, wave and current shear, thereby increasing the preservation potential of bedforms and delicate features of their bedding surfaces. Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, SP Departamento de Geologia Escola de Minas Universidade Federal de Ouro Preto, MG Departamento de Ecologia e Biologia Evolutiva Universidade Federal de São Paulo, SP Instituto de Biociências Departamento de Zoologia Universidade Estadual Paulista “Júlio de Mesquita Filho”, SP Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, SP Instituto de Biociências Departamento de Zoologia Universidade Estadual Paulista “Júlio de Mesquita Filho”, SP

Made available in DSpace on 2021-06-25T10:27:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Several sag-type basins apparently developed from rift systems, but there is no consensus about how and if these grabens influenced the sedimentation of the post-rift thermal subsidence phase. The Ediacaran Jaibaras Rift Basin is one of the best-exposed sedimentary records among the NE Brazil late Precambrian - early Cambrian rift system, cropping out at the eastern margin of the intracratonic Parnaíba Basin and extending below it towards the west. Here we present detrital zircon U-Pb ages of rocks from the Jaibaras (Aprazível Formation) and Parnaíba (Ipu Formation) basins, in order to understand the provenance patterns, maximum depositional ages (MDA) and age relationship between these units. The MDA for the Aprazível Formation (c. 499 ± 5 Ma) indicates a Cambrian age for the upper part of the Jaibaras Basin. The bulk U-Pb data indicate that the Ipu Formation started to deposit during late Cambrian and/or Early Ordovician time, despite its MDA (c. 528 ± 11 Ma) being older than that of the Aprazível Formation. Detrital zircon provenance suggests that the primary source areas for the early deposits of the Parnaíba Basin were mountains related to the Brasiliano Orogeny to the south and SE (e.g. Rio Preto and Riacho do Pontal metamorphic belts). Finally, our data emphasize the key change in source areas from the rift to the initial deposition of the intracratonic phase, indicating major depositional style changes between both basins after the Gondwana assembly. Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24-A, Bela Vista, 178 Departamento de Geologia Universidade Federal de Ouro Preto Campus Morro Do Cruzeiro S/n Instituto de Engenharia Ciência e Tecnologia Universidade Federal Dos Vales Do Jequitinhonha e Mucuri (UFVJM) Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24-A, Bela Vista, 178

Made available in DSpace on 2021-07-14T10:54:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-21. Added 1 bitstream(s) on 2021-07-14T11:41:10Z : No. of bitstreams: 1 S2317-48892021000100303.pdf: 9877652 bytes, checksum: 8f99643b443c0258fa2d0b3ec0b4c75e (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras The Aptian Crato Formation is world renowned for its well-preserved fossils in microbially-induced laminated limestones, which are regarded as one of the main Cretaceous Konservat-Lagerstätte of the geological record. Detailed stratigraphic investigation and mapping of the up to 90-m-thick Crato Formation at the eastern border of the Araripe Plateau allowed recognition of a regionally persistent fossil-bearing muddy interval, herein defined as the Caldas Bed. At its type locality, it is defined as an up to 2-m-thick coarsening-upward succession of grey/green mudstone and interbedded sandy siltstone and claystone. The 0.85- to 2-m-thick interval was recognized in several localities along the outcrop belt, and it is bounded by sharp, lower (Konservat-Lagerstätte limestone) and upper (sandstone and heterolithic facies) contacts. Despite previous literature data suggesting the presence of marine mollusks, the bed contains freshwater bivalves, small gastropods, spinicaudatans, plant remains, trace fossils, and rare ostracods. The Caldas Bed records benthic paleocommunities representing a short-term isochronous regional freshening event, marked by abrupt changes in sedimentation pattern, bathymetry, salinity, oxygenation and water chemistry. Universidade Federal do Paraná, Departamento de Geologia Universidade Estadual Paulista “Júlio de Mesquita Filho”, Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, Instituto de Biociências Friedrich-Alexander-Universität Erlangen-Nürnberg, FG Paläoumwelt Universidade Estadual Paulista “Júlio de Mesquita Filho”, Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, Instituto de Biociências FAPESP: 2016/13214-7; 2017/22036-8; 2017/20803-1; 2018/01750-7 CNPq: 401039/2014-5 Petrobras: 2014/00519-9

Made available in DSpace on 2021-06-25T15:02:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 An alternative hypothesis concerning the paleoecological and paleoenvironmental depositional conditions of the Crato Konservat-Lagersta?tte (CKL), Crato Formation, Aptian, NE Brazil, one of the most extraordinary Gondwana fossil sites, is proposed. Following an actualistic approach, the ecology of extant relatives of the most abundant and diverse fossil groups recorded in the CKL (i.e., vascular plants, arthropods, fishes, and tetrapods) is considered. Data is based on an extensive literature review followed by a re-examination of recently collected fossils. This approach allowed a detailed appraisal of the stratigraphic/ecological distribution of the main fossil groups preserved in the CKL. Plant and animal groups are recorded in three main stratigraphic intervals, named Intervals I?III in ascending order. Most fossils are to be considered autochthonous to parautochthonous and have been preserved in distinct stages of base-level fluctuations within a shallow lacustrine depositional system, subject to periodic flooding in large, depressed areas. Exceptional preservation in such environments was mediated by microbially-induced processes (i.e., microbial mat entombment), mostly in the coastal areas of the alkaline lake. Based on the distinct sedimentary facies and autecological attributes of dominant paleobioindicators, a new paleoenvironmental model for the CKL is proposed, encompassing a seasonal, semi-arid, shallow lacustrine wetland. Faunal and floral content were ecologically arranged in long-lasting aquatic zones, surrounded by periodically flooded mesophytic ecotones and outer xeric habitats, as in the modern alkaline lake Chad in Africa. Our data show the relevance of multiproxy analyses (i.e., paleontological, sedimentological, geochemical, and stratigraphic) of exceptional fossil sites for assessing paleoenvironmental conditions in depositional settings subject to continuous base-level changes, such as those existing in complex, present-day wetland ecosystems. The recognition of key parameters in ancient wetlands is of great importance concerning the formation of non-marine Konservat-Lagersta?tten in the geological record. Univ Fed Mato Grosso, Dept Biol & Zool, Av Fernando Correa Costa 2367, BR-78060900 Cuiaba, Mato Grosso, Brazil Univ Fed ABC, Ctr Ciencias Nat & Humanas, Ave Estados 5001, BR-09210580 Santo Andre, SP, Brazil Univ Fed Ouro Preto, Dept Geol, Escola Minas, BR-35400000 Ouro Preto, MG, Brazil Univ Fed Parana, Dept Geol, Inst LAMIR, Av Cel Francisco H Santos 100, BR-81531980 Curitiba, PR, Brazil Univ Fed Mato Grosso, Inst Ciencias Nat Humanas & Sociais, Av Alexandre Ferronato 1-00, BR-78557267 Sinop, Mato Grosso, Brazil Univ Fed Mato Grosso, Dept Bot & Ecol, Av Fernando Correa,Costa 2367, BR-78060900 Cuiaba, Mato Grosso, Brazil Univ Estadual Paulista, Setor Zool, Inst Biociencias, BR-18618000 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Geol, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, SP, Brazil Univ Sao Paulo, Inst Energia & Ambiente, BR-05508010 Sao Paulo, Brazil Univ Sao Paulo, Inst Geociencias, BR-05508010 Sao Paulo, Brazil Univ Autonoma Madrid, Dept Biol, Ctr Integrat Palaeobiol, E-28049 Madrid, Spain Univ Autonoma Madrid, Dept Biol, Unidad Paleontol, E-28049 Madrid, Spain Univ Estadual Paulista, Setor Zool, Inst Biociencias, BR-18618000 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Geol, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, SP, Brazil

Despite the absence of metazoans, structures resembling animal traces are common in a soda lake from the western Brazil Pantanal wetland. Pantanal soda lakes are ecologically extreme environments that preclude complex life, allowing extremophiles to flourish. Direct observation indicates that these structures are pseudotraces, representing groove marks that result from the interaction of wave-transported floating rafts of epibenthic microbial mat fragments with the substrate. Variations in wind/wave direction and intensity result in marks of different size and morphology. The most common pseudotraces are simple and slightly curved, narrow grooves (type 1), whereas others are straight and present raised lateral ridges (type 2). Both are V-shaped in cross section. Type 3 comprises long, sinuous, shallow grooves, displaying internal crescentic laminated infill and U-shaped cross section. The similarity of these pseudotraces to Ediacaran structures usually interpreted as animal trace fossils suggests that care should be exercised in their analysis. A set of criteria is proposed to differentiate microbially induced pseudotraces from trace fossils. Analysis of Ediacaran structures needs to be performed on a case-by-case basis, taking into account morphology, orientation, and preservation style of the structure, sedimentary environment, and presence or absence of microbial mats., Centro de Investigaciones Geológicas

Made available in DSpace on 2020-12-10T17:38:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01. Added 1 bitstream(s) on 2021-07-15T15:24:48Z : No. of bitstreams: 1 S2317-48892020000100308.pdf: 17706543 bytes, checksum: 0092f7bb6639cbc2ea98622d4a26fcbc (MD5) Soft-sediment deformation (SSD) structures are widespread in the sedimentary record, and numerous triggering mechanisms can induce its development, including glaciation, earthquakes, overloading, ground-water fluctuations, and wave movement. The Late Cretaceous Uberaba Formation preserves SSD structures as small- and large-scale load casts and associated flame structures, pseudonodules, and convolute laminations observed in the contact of three well-defined intervals among fine- to coarse-grained lithic and conglomeratic sandstone with fine-grained arkose and mudstone beds. Based on the morphology of the SSD structures, sedimentary facies of the Uberaba Formation, and similarities with previous observations in the geological record and laboratory models, these features are assigned to liquefaction-fluidization processes as the major deformational mechanism triggered by seismic and aseismic agents. We propose that a deformation occurred just after the sedimentation triggered by seismic shock waves and overloading, induced by the sudden deposition of coarse-grained sandy debris on fine-grained sediments. Some of these structures can be classified as seismites, providing evidence of intraplate seismicity within the inner part of the South American Platform during the Late Cretaceous. This seismic activity is likely related to the uplift of the Alto Paranaiba High along reactivations of regional structures inherited from Proterozoic crustal discontinuities and coeval explosive magmatism of the Minas-Goias Alkaline Province. Univ Fed Uberlandia, Uberlandia, MG, Brazil Univ Estadual Paulista, Rio Claro, SP, Brazil Univ Fed ABC, Santo Andre, SP, Brazil Univ Estadual Paulista, Rio Claro, SP, Brazil

Made available in DSpace on 2020-12-12T01:13:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) National Aeronautics and Space Administration Most Precambrian sediment-hosted barites have been interpreted to be diagenetic, hydrothermal exhalation, or methane-seepage in origin. Seafloor barite precipitates and void-filling barite cements in basal Ediacaran cap dolostones have been interpreted as sedimentary and early diagenetic in origin, and they have been used to infer ocean geochemistry in the aftermath of the terminal Cryogenian (or Marinoan) Snowball Earth glaciation. Barite crystals precipitated syndepositionally from seawater or authigenically from marine porewaters can potentially offer insights into Neoproterozoic ocean geochemistry. In this study, we analyzed void-filling barite cements from the basal Ediacaran Sete Lagoas cap dolostone to determine whether the barite records seawater geochemical signatures and whether it experienced post-depositional hydrothermal alteration. Sete Lagoas barite occurs as veins and major void-filling cement in multiple horizons, sometimes interbedded with carbonate fans. Barite crystals, commonly forming rosettes, grew upwards and downwards as radiating bladed crystals, isolated crystals in the matrix, and inclusions within carbonate fan crystals. Sulfur isotope compositions of coexisting barite and carbonate-associated sulfate (CAS) show similar values, suggesting a similar sulfate source, potentially seawater sulfate from a shallow marine environment. Assuming that CAS was sourced from seawater sulfate, we infer that the Sete Lagoas barite was precipitated from marine porewaters with seawater as a source of the sulfate. Carbonaceous material (CM) and fluid inclusions in barite crystals share a similar thermal history with a peak temperature in the range of 206–257 °C. CM was not detected in the host rock, possibly due to pervasive dolomitization, thermodegradation of CM or the fine-grained nature of the host rock. Estimated temperatures and salinity based on fluid inclusions are both higher than seawater, suggesting that hydrothermal activity, perhaps those related to Mississippi-Valley type mineralization in the São Francisco Craton, may have influenced the Sete Lagoas barite. Thus, although the Sete Lagoas barite may have originally precipitated from seawater or marine porewaters in communication with seawater, it may have been subsequently influenced by hydrothermal activity and therefore a more thorough diagenetic assessment must be done before the Sete Lagoas barites can be used to infer seawater geochemistry and environment in the aftermath of Marinoan Snowball Earth. Department of Applied Geology Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) Department of Geosciences Virginia Tech Department of Earth and Atmospheric Sciences University of Alberta Department of Applied Geology Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) FAPESP: 2015/07391-0 FAPESP: 2017/19023-1 National Aeronautics and Space Administration: 80NSSC18K1086

The Pantanal is the most conserved biome in Brazil and among the last wild refuges in South America, but intensification of agriculture and other land use changes present challenges for protecting this exceptionally biodiverse wetland ecosystem. m. Recent studies have shed new light on the origins and biogeochemistry of a suite of >600 small saline-alkaline lakes in Nhecolândia, a floodplain setting located south ofthe Taquari River in south-central Pantanal. These soda lakes form a unique aquatic environment in Pantanal and nascent research on their geomicrobiology suggests that their biota may be analogous to early life, and extreme life in Earth?s deep biosphere. We argue that the conservation of the soda lakes in the lower Nhecolândia region should be an important strategic component of any conservation plan that aims to mitigate the advance of unsustainable land-use change in the Pantanal. Soda lake conservation has important implications for the carbon cycle, as these landforms sequester carbon dioxide and transmit considerably lower concentrations of methane in comparison to macrophyte-rich freshwater lakes in the region. Further, minerals precipitated in the saline-alkaline lakes are leveraged for cattle consumption, and therefore the continued presence of the lakes is critical for allowing pantaneiro ranchers to pursue certified organic, sustainable beef production systems. Beyond protecting soda lakes and their surrounding forests (mata de cordilheiras) for food systems security, the conservation strategy would also allow further research of little studied extremophile biodiversity and biogeochemistry, with potential for biotechnological innovations attendant to UN Sustainable Development Goals. Made available in DSpace on 2019-09-26T00:43:53Z (GMT). No. of bitstreams: 1 ThesodalakesNhecolandia2019.pdf: 3939848 bytes, checksum: 11e2681e26fc1e0d00afe58641bff8b6 (MD5) Previous issue date: 2019

Made available in DSpace on 2020-12-12T01:44:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The fossil-rich carbonate deposits of the Aptian Crato Formation, Araripe Basin (Brazil) are one of the main Cretaceous Konservat-Lagerstätten of Gondwana, and have come to fame globally. However, information on fossils from deposits other than the famous laminites of the basal part of the unit is scarce. Herein, we describe the first bivalves of the suborder Silesunionidina Skawina and Dzik, 2011 in the order Unionida Gray, 1854 from South America. The specimens were collected from a 0.3–1-m-thick grey to yellow mudstone interval located 0.3 m above the laminated limestones of the lower part of the Crato Formation at Nova Olinda, State of Ceará. They comprise exquisite composite, internal and external moulds, preserving key anatomical characters. Based on the analysis of muscle scars, hinge and ornamentation, these bivalves are here assigned to a new genus and species, Cratonaia novaolindensis gen. et sp. nov. The presence of a series of small pedal elevator scars linearly arranged on the external wall of the umbonal cavity indicates that this is a member of the suborder Silesunionidina. The new form is the by far youngest representative of this group. Closely related bivalves were previously reported from Triassic deposits of Australia, Africa, Europe and potentially India. Detailed stratigraphic, sedimentological and taphonomic observations indicate that the new taxon thrived in a freshwater lake. The occurrence of Silesunionoidea in the Lower Cretaceous of South America indicates that the condition of the musculature in Mesozoic freshwater mussels needs to be established to assign them confidently at family level. Departamento de Geologia Aplicada Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista/UNESP, Avenida 24-A, Bela Vista, 178 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior S/n, 510 GeoZentrum Nordbayern FG Paläoumwelt Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr 28 Department of Animal Physiology Faculty of Biology University of Warsaw, Ilii Miecznikowa 1 CASP, West Building, Madingley Rise, Madingley Road Departamento de Geologia Aplicada Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista/UNESP, Avenida 24-A, Bela Vista, 178 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior S/n, 510 FAPESP: 16/13214-7 FAPESP: 17/20803-1 FAPESP: 17/22036-8 Petrobras: 2014/00519-9 CNPq: 304800/2017-1 CNPq: 401039/2014-5

Made available in DSpace on 2020-12-10T19:51:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Petrobras Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) The Sete Lagoas Formation (Ediacaran), located in the central part of the Sao Francisco Craton (Brazil), consists of limestones and dolostones deposited in very shallow waters in the inner part of the carbonate platform. Four breccia types occur throughout the stratigraphic succession: evaporitic breccia with tepees, flat-pebble breccia, hydrothermal breccia and brecciated stromatolites. Here we combine a detailed sedimentological and stratigraphic analyses of the flat-pebble breccia in order to determine its origin and the processes and environmental conditions that originated these brecciated facies. The studied interval consists of a 20 m thick succession of tabular beds composed of flat-pebble breccia interbedded with laminated microbialites. In these breccia beds, the clasts are usually platy or oblate with angular edges and are mainly disposed horizontally within the sedimentary bed, suggesting that they were not transported or reworked. The presence of microbialite clasts with sharp edges and vertices in the Sete Lagoas flat-pebble breccia suggests that the lithification process started very early in diagenesis and, even the sediments exposed at the bottom were, at least, partially lithified. Some breccia levels show bidirectional imbrication and clast size analyses reveal a NE-SW long-axis clast orientation whereas square clasts tend to fill the space among oriented clasts. Breccia clasts are vertically oriented and show deformation features increasing upwards, typically of deforming beds formed by ascendant expulsion of liquefied sediment. Disrupted layers or presenting folds and synsedimentary faults commonly occur confined between undeformed beds. Other evidences of liquefaction and soft-sediment deformation are the injection structures, as flame and load cast-like features, in the base of the brecciated beds. These structures commonly penetrate the upper bed and disrupt the sedimentary layer immediately above promoting local brecciation. These features are found both in modern and ancient deposits of seismic influence, which suggests a similar origin for the Sete Lagoas flat-pebble breccia. Thus, the processes that led to the formation of the studied flat-pebble breccia are interpreted as seismically triggered, since: a) the breccia beds are laterally continuous and extend for several kilometers; b) the breccia beds are restricted to a 20 m thick stratigraphic interval; c) the clasts of the breccia are the same lithology of non- deformed beds below and above the interval of breccia; d) the interbedding of breccia beds and laminated microbialite beds is recurrent; e) the breccia beds are subhorizontal and present irregular upper and lower contacts; f) the presence of liquefaction structures and dyke injection. Thus, this seismic-triggered breccia deposits represent the product of the synsedimentary tectonism occurred within the Sao Francisco Craton during the terminal Ediacaran and correspond to a very well-defined local stratigraphic marker in the Bambui Basin. The seismic activities could be related to the NW regional faults in the regional Paleoproterozoic basement of the study area, which were reactivated during the deposition of the Sete Lagoas Formation in the Ediacaran Period. Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Petrol & Metalogenia, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Fed Sao Paulo, Dept Ecol & Biol Evolut, Rua Prof Artur Riedel 275, BR-09972270 Diadema, Brazil Univ Fed Minas Gerais, Inst Geociencias, Ave Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Petrol & Metalogenia, Ave 24A,1515, BR-13506900 Rio Claro, Brazil FAPESP: 2015/07391-0 FAPESP: 2018/26230-6 CNPq: 301294/2018-6 CNPq: 447449/2014-1 CNPq: 444070/2014.1 Petrobras: Sigitec 2014/-00519-9 FAPEMIG: APQ-01711-14

Made available in DSpace on 2022-05-01T07:58:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Petrobras The Lower Cretaceous Araripina Formation records deposition in a distributive fluvial system that is a part of the post-rift sequence of the Araripe Basin, NE Brazil. Following the opening of the Brazilian Equatorial Margin, the reactivation of regional faults of the Paleoproterozoic basement resulted in tectonic subsidence and formation of a regional-scale DFS. The Araripina Formation is an up to 40-m-thick succession of rhythmically interbedded sandstone and mudstone, organized in two depositional sequences separated by a regional disconformity. We recognized and grouped nine sedimentary facies into six facies associations that we interpreted as deposits of meandering channels, ribbon channels, minor channels, floodplain, lateral and terminal splays, and distal floodplain. The lower sequence facies associations suggest deposition in the medial to distal part of a distributive fluvial system in a tectonically active, interior basin subjected to episodic flooding. The periodic inundations were responsible for activating ephemeral channels and producing sheetfloods, followed by deposition of lateral and terminal splays in distal flooded areas. Syn-sedimentary deformation structures are present in rhythmite facies (truncating surfaces, load structures, injectite and convoluted folds) in the upper part of the lower sequence. The upper sequence was formed after a period of intense tectonic activity in a large distal floodbasin dominated by suspension. The deposition culminates in an interval with pedogenetic deposits cross-cut by a regional disconformity with the upper Exu Formation. Paleocurrent data from both depositional sequences indicate paleodepositional slope towards southeast and east with source-areas located to the northwest and west. This pattern is similar to that observed in the lower Santana Group and opposite to the westward direction of sedimentary transport in the overlying Exu Formation implying significant change of source region, basin topography and continental paleodrainage in the Araripe Basin after the Albian. Department of Geology IGCE São Paulo State University, Avenida 24A, 1515 Department of Geology School of Mines Federal University of Ouro Preto, Morro do Cruzeiro CECS Federal University of ABC, Avenida dos Estados, 5001 Geography Institute Federal University of Uberlândia, Rodovia LMG-746 Km 01 Department of Geology IGCE São Paulo State University, Avenida 24A, 1515

Made available in DSpace on 2021-06-25T10:55:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-01 Agência Nacional do Petróleo, Gás Natural e Biocombustíveis Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Soft-sediment deformation structures are conspicuous features found in both ancient and modern, shallowly buried, loose, and water-saturated sediments related to diverse depositional environments. Numerous triggering mechanisms can induce their development, including seismicity, glaciotectonics, overload, and bioturbation. The presence of soft-sediment deformation in the Jurassic fluvial-eolian Pirambóia Formation has been known for a long time and was usually associated with seismic-induced triggers. Recently described synsedimentary structures in wet interdune deposits from the lower part of this unit, close to its type area in São Paulo State, southeastern Brazil, are now interpreted as true cross-section tracks produced by large tetrapods based on examples from the literature and morphological analyzes. Based on their age, size, and comparisons with dinosaur tracks described in Jurassic lithostratigraphic units from Paraná Basin in Brazil (Guará Formation) and Waterberg Basin (Etjo Formation), we suggest here, for the first time, that some of those deformational structures were produced by dinosaurs. Furthermore, the cross-section tracks from the Pirambóia Formation in São Paulo State exceed in size the tracks with therapsid affinity described in the Permian-Triassic unit in southern Brazil, hindering their full correlation. This finding may potentially represent the oldest evidence of the presence of dinosaurs in the São Paulo State territory, expanding our knowledge of the poorly known Jurassic tetrapod fauna of Brazil. Additionally, these cross-section tracks reinforce the possible correlation, at least in part, of the Pirambóia Formation in its northern occurrence (near to its type area) with the Jurassic Guará Formation from southern Brazil. Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista-UNESP, Avenida 24-A, 1515 Bela Vista, Cx. P. 178 Laboratório de Paleoecologia e Paleoicnologia Departamento de Ecologia e Biologia Evolutiva Universidade Federal de São Carlos - UFSCar Instituto de Geografia Universidade Federal de Uberlândia, Rodovia LMG-746 Km 01 Setor de Zoologia Instituto de Biociências Universidade Estadual Paulista-UNESP, Distrito de Rubião Junior, s/n, 510 Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista-UNESP, Avenida 24-A, 1515 Bela Vista, Cx. P. 178 Setor de Zoologia Instituto de Biociências Universidade Estadual Paulista-UNESP, Distrito de Rubião Junior, s/n, 510 CNPq: 141220/2018–0

Made available in DSpace on 2018-12-11T17:13:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-08-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Geologic events related to the opening of the South Atlantic Ocean deeply influenced the sedimentary record of the Araripe Basin. As consequence, upper stratigraphic units of the basin record a marine ingression in northeastern Brazil during the late Aptian. The timing and stratigraphic architecture of these units are crucial to understand the paleogeography of Gondwana and how the proto-Atlantic Ocean reached interior NE Brazil during the early Cretaceous. This marine ingression is recorded in the Araripe Basin as the Romualdo Formation, characterized by a transgressive-regressive cycle bounded by two regional unconformities. In the eastern part of the basin, the Romualdo depositional sequence comprises coastal alluvial and tide-dominated deposits followed by marine transgressive facies characterized by two fossil-rich intervals: a lower interval of black shales with fossil-rich carbonate concretions (Konservat-Lagerstätten) and an upper level with mollusk-dominated shell beds and shelly limestones. Following the marine ingression, an incomplete regressive succession of marginal-marine facies records the return of continental environments to the basin. The stratigraphic framework based on the correlation of several sections defines a transgressive-regressive cycle with depositional dip towards southeast, decreasing in thickness towards northwest, and with source areas located at the northern side of the basin. The facies-cycle wedge-geometry, together with paleocurrent data, indicates a coastal onlap towards NNW. Therefore, contrary to several paleogeographic scenarios previously proposed, the marine ingression would have reached the western parts of the Araripe Basin from the SSE. Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24A, 1515 Curso de Geologia Instituto de Geografia Universidade Federal de Uberlândia, Rodovia LMG 746, Km 1 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista - Unesp Distrito de Rubião Júnior GeoZentrum Nordbayern FG Paläoumwelt Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr 28 Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24A, 1515 Departamento de Zoologia Instituto de Biociências Universidade Estadual Paulista - Unesp Distrito de Rubião Júnior FAPESP: 2004/15786-0 Petrobras: 2014/00519-9 FAPESP: 2014/27337-8 CNPq: 401039/2014-5

Made available in DSpace on 2018-11-26T17:20:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anoxic to dysoxic conditions must have existed in the Parana Basin during the deposition of the Permian oil-bearing shales of the Irati Formation, reflecting the marine isolation of the basin from the Panthalassic Ocean. In this environment, benthic invertebrates are extremely rare, in contrast to the overlying Serra Alta and Teresina formations, which were deposited in dysoxic/oxic waters, respectively. Hence, the abundant shallow-burrowing, endemic bivalves recorded in the shales of the basal portion of the Irati Formation are one of the most distinctive features of this stratigraphic interval. Their preservation in offshore deposits is, however, a product of storm flows in shallow waters that swept the shells to distal settings. Subsequently, these were sorted by long-lasting shelf currents that produced dense (2-5 shells/20 cm(2)) pavements in which shells in a hydrodynamically stable posture (convex-up) predominate, forming thin, complex shell concentrations despite their simple internal stratigraphy. The new data presented here have important paleoecologic, paleogeographic and evolutionary implications and indicate that (a) during the deposition of the oil-rich shales of the Irati Formation, numerous benthic bivalves thrived in the contemporary shallow-water bottoms of the Parana Basin; (b) the mono- to paucispecific nature of the studied shell-rich pavements is, in part, due to hydrologic shell transport; and (c) restricted connections to open ocean waters (Panthalassa) existed during Irati times. Therefore, the origin of the endemic Passa Dois molluscan fauna occurred somewhere between the interval represented by the underlying Palermo Formation and the basal portion of the Irati Formation. Finally, these endemic bivalves appeared at least-10 million years earlier than previously thought. (C) 2016 Elsevier B.V. All rights reserved. Univ Sao Paulo, Inst Geociencias, Programa Posgraduaca Geoquim Geotecton, Rua Lago 562, BR-05508080 Sao Paulo, SP, Brazil Univ Estadual Paulista, Inst Geociencias Ciencias Exatas, Dept Appl Geol, Avenida 24-A,Bela Vista,178, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, Distrito Rubrdo Jr S-N,510, BR-18618970 Botucatu, SP, Brazil Univ Estadual Paulista, Inst Geociencias Ciencias Exatas, Dept Appl Geol, Avenida 24-A,Bela Vista,178, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, Distrito Rubrdo Jr S-N,510, BR-18618970 Botucatu, SP, Brazil FAPESP: 2012/12508-6 CNPq: 302903/2012-7 CNPq: 444070/2014-1

Made available in DSpace on 2020-12-12T02:17:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed or splayed articulated valves, some of them potentially in life position, forming an autochthonous to parautochthonous assemblage. Monginellopsis bellaradiata nov. gen., nov. sp. shares key characters with the Trigonioidoidea: (i) the anterior pedal retractor muscle scar is clearly separated from the anterior adductor muscle scar; (ii) the shell has fold-like radial ribs on the posterior half; (iii) a right valve anterior tooth has a striated facet. Araripenaia elliptica nov. gen., nov. sp. is the most abundant and widely distributed unionid of the Crato Formation. Its ornament of anterior inverted V-shaped riblets, and central and posterior radial and sub-radial riblets resembles modern and fossil Hyriidae from the Americas, but also Trigonioidoidea from Eurasia. Its dentition of two smooth anterior pseudocardinals and two smooth posterior laterals in each valve provides no further clues for systematic assignment; muscle scars are not preserved. Assignment to the Hyriidae would make Araripenaia the oldest member of this family known from South America. Moreover, this bivalve assemblage of trigonioidoidids, hyriids, and previously reported silesunionoids suggests palaeobiogeographic links to other areas in both Gondwana and Laurasia. Departamento de Geologia Aplicada Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista/UNESP, Avenida 24-A 1515 Instituto de Biociências Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior s/n, 510 Instituto Lamir Universidade Federal do Paraná Setor de Ciências da Terra Centro Politécnico, Av. Cel. Francisco H. dos Santos, 100, Jardim das Américas GeoZentrum Nordbayern FG Paläoumwelt Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr 28 Department of Animal Physiology Faculty of Biology University of Warsaw, Ilii Miecznikowa 1 CASP West Building, Madingley Rise, Madingley Road Departamento de Geologia Aplicada Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista/UNESP, Avenida 24-A 1515 Instituto de Biociências Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior s/n, 510 FAPESP: 16/13214-7 FAPESP: 17/20803-1 FAPESP: 17/22036-8 FAPESP: 18/01750-7 Petrobras: 2014/00519-9 CNPq: 304800/2017-1 CNPq: 401039/2014-5

This work presents the results of a palaeontological analysis focused on twenty-six species sampled in five sections of the Tamengo and Guaicurus formations, Corumba and Ladario regions: Corcal and Laginha quarries, Porto Sobramil, Porto Figueiras and Ecoparque Cacimba. Besides, palaeoecological and palaeoenvironmental inferences are presented based on the occurrence of this fossil assemblage. Cloudina carinata Cortijo et al., 2010, previously documented in Spain and Siberia, presents an unprecedented occurrence in the American continent, in siltstones of the Tamengo Formation at Porto Figueiras section, Municipality of Corumba, Mato Grosso do Sul State, Brazil. The biota of the Tamengo Formation is updated and composed of three biomineralizing metazoans, including poriferan spicules, putative sponge gemmule, and a sessile epibiontic prokaryotic colony. The present work also deals with the taxonomy and stratigraphic distribution of four ichnospecies and three vendotaenid species that integrate the updated benthic fauna for the upper portion of Corumba Group. The species diversity of the Tamengo Formation was complemented by the occurrence of sixteen microfossil species that possibly represent a marine planktic assemblage. A dramatic change was identified in the palaeoenvironmental conditions of the Tamengo to Guaicurus formations, followed by a mass extinction event, possibly linked to the global Ediacaran- Cambrian mass extinction. In addition, organic-walled microfossils were prepared and analyzed from sections of three countries: nine species from the Nomtsas Formation, Namibia; four species from the Tagatiya Guazu Formation, Paraguay; and six species from the Dengying Formation, China. An international biostratigraphic essay consisting of six biozones is proposed for the uppermost Ediacaran and one biozone for the earliest Cambrian.

A well preserved assemblage of organic-walled microfossils is described from the Alicia and Cerro Negro formations of the La Providencia Group. The microbiota is dominated by Leiosphaeridia species (L. minutissima, L. tenuissima, L. crassa and L. jacutica) and comprises colonial sphaeroids (Synsphaeridium sp.) and filamentous microfossils of the genus Siphonophycus. The assemblage is assigned to the Late Ediacaran Leiosphere Palynoflora (LELP), which is consistent with the occurrence of the discoidal fossil Aspidella (

Made available in DSpace on 2019-10-06T17:06:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Petrobras Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The Aptian is the age of the evaporitic transitional megasequence in the Brazilian marginal basins as well as in the interior rift basins of the northeast region. The Marizal Formation is interpreted as a fluvial system developed in the inherited rift axis of the Tucano Basin. In its middle portion, after a quick transgressive event, a mud-dominated interval took place, which is enclosed in the Amargosa Bed. This transgressive marker bed is rich in fish fossils with Tethyan affinity attesting to an estuarine environment in the southern portions of the basin. The same transgressive event occurs in the Barbalha Formation of the Araripe Basin, where a mud-dominated lacustrine system is interpreted in the Batateira Bed. While lakes developed in the Araripe Basin and a transitional marine environment is attested to the southern portions of the Tucano Basin, there is no information of how these systems were interconnected. Here we discuss sedimentologic, stratigraphic and geochemical data of the Amargosa Bed in the North Tucano Basin, correlating it with time equivalent marker beds of other locations in the Northeast Brazil. Our data show that deposition of the mixed carbonate-mud interval of the North Tucano Basin was developed in a saline lake with local evidences of seismic-induced soft-sediment deformation structures. Although climate seasonality controlled high-frequency base-level changes, our findings reveal that local fault reactivation was responsible for the space generation, triggering the lake formation in the basin depocenter. This situation is uncommon for thermal subsiding basins that lack mechanical influence and have several implications for the evolution of intracontinental rift basins of the Brazilian Cretaceous. Also, lakes from Araripe, Jatobá and North Tucano basins were probably connected by the continental paleodrainage existent in the Aptian, carrying sediments to the estuaries developed in the Central and South Tucano basins and, thus, to the developing South Atlantic Ocean. Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24A, 1515 Faculdade de Tecnologia Universidade Estadual de Campinas, R. Paschoal Marmo, 1888, Jd. Nova Itália Laboratório de Geologia Sedimentar e Ambiental (LAGESE) Departamento de Geologia Universidade Federal de Pernambuco Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24A, 1515 Petrobras: 2014/00519-9 FAPESP: 2016/19736-5

Made available in DSpace on 2019-10-04T12:35:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Significant Ediacaran paleoenvironmental changes recorded in the mixed carbonate-siliciclastic Bambui Basin, east-central Brazil, outcrop in one of the best-preserved sites, the Januaria paleo-high. From a detailed strati graphic and chemostratigraphic approach (carbon and oxygen isotopes, total organic carbon, total sulfur and selected elements abundances), we identified transgressive-regressive intervals and depositional settings within the Barnhill Group stratigraphy and developed a new model for the origin of the extremely positive Middle Bambui Excursion (MIBE) present in the middle section of the basin. A post-Marinoan cap carbonate interval is recorded in the first similar to 10 m, preserving aragonite pseudomorph fans, barite-rich layers and negative delta C-13 anomaly. A hiatus separates the cap carbonate from the late Ediacaran succession that makes up the remaining Bambui Group. The younger intervals preserve both siliciclastic (middle Serra de Santa Helena Formation) and carbonate (middle/upper Sete Lagoas and Lagoa do Jacare formations) shallow-water depositional settings, requiring tectonic influence or climatic changes in source areas. The MIBE yields delta C-13 values as high as +14 parts per thousand and extends for about 350 m, from the upper Sete Lagoas Formation to the lower Serra da Saudade Formation. We suggest a model of a restricted basin setting that favored local carbon isotopic signals in the delta C-13 record of sedimentary carbonates through preferential weathering of ancient carbonate platforms on the continent and higher burial rate of authigenic carbonate. This scenario caused the global delta C-13 budget to be affected by an offset of, at least, + 4 parts per thousand in sedimentary carbonates deposited on the Sao Francisco craton and along its margin during the terminal Ediacaran. Many previous studies suggested a restricted nature for the middle Bambui Basin, which probably resulted from the central position of the Sao Francisco paleocontinent within the mosaic of collisional blocks during the SW Gondwana amalgamation. Univ Fed Minas Gerais, Inst Geociencias, Ctr Pesquisas Manoel Teixeira Costa, Campus Pampulha,Av Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG, Brazil Univ Estado Rio De Janeiro, Fac Geol, Dept Paleontol & Estratig, Av Sao Francisco Xavier 524, BR-20550013 Rio De Janeiro, RJ, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, SP, Brazil Univ Fed Pernambuco, NEG LABISE, Dept Geol, Av Arquitetura S-N, BR-50670901 Recife, PE, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24A,1515, BR-13506900 Rio Claro, SP, Brazil CNPq: 447449/2014-1 CNPq: 444070/2014-1 FAPEMIG: APQ-01711-14 FAPEMIG: APQ-00914-14 FAPEMIG: PPM-00539-15 FAPESP: 2015/07391-0

Made available in DSpace on 2019-10-06T16:10:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-01 Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The Cretaceous (upper Aptian) Romualdo Formation of the Araripe Basin, northeastern Brazil, is a marine-influenced, predominantly fine-grained siliciclastic unit. In the eastern part of the basin, it corresponds to a depositional sequence composed of two transgressive-regressive cycles. Low-diversity benthic macrofaunas document high-stress conditions. Their palaeoecological and taphonomic analysis allows for the detailed reconstruction of the palaeoenvironments and of the temporal changes in the palaeoecosystem. The transgressive part of the lower cycle is a black shale with calcareous concretions that contain excellently preserved fishes and other vertebrates (the famous “Santana fossils”), but apart from abundant ostracods and rare decapod crustaceans, benthic faunal elements are very rare due to anoxic to dysoxic conditions. A low-diversity parautochthonous molluscan fauna of small bivalves and gastropods records fluctuating dysoxic conditions during early regression. Towards the top of the measured sections (late regression), thin gastropod shell beds become conspicuous. At the top of the sections decimetre-thick shell concentrations show signs of reworking and a greater marine influence (transgressive part of the upper cycle). The distribution pattern of three benthic associations and two assemblages is almost equally shaped by three environmental parameters: The low overall species diversity, small size of the fauna, and the lack of stenohaline elements suggest lowered and fluctuating salinity conditions. Fluctuating redox conditions with anoxia to dysoxia, identified especially in the lower parts of the succession, and substrate were the other two factors shaping the faunal distribution. The late Aptian sedimentary and faunal history of the eastern part of the basin indicates restricted marine influence, coupled with increasing freshwater input during phases of sea-level lowstand, and low-energy conditions offshore, which led to widespread anoxia, especially in the lower part of the formation. Thus, palaeoecological analyses are an excellent tool to disentangle the various environmental parameters that shaped the palaeoenvironments of the basin, to understand more closely its Fossil-Lagerstätten, and to corroborate and fine-tune the sequence stratigraphic framework. GeoZentrum Nordbayern FG Paläoumwelt Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr 28 Universidade Federal do Amazonas ICE - Instituto de Ciências Exatas Avenida Rodrigo Otávio, Japiim Instituto de Biociências Departamento de Zoologia Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior s/n, 510 Institut für Geologische Wissenschaften Fachrichtung Paläontologie Freie Universität Berlin, Malteserstraße 74-100 Curso de Geologia Instituto de Geografia Universidade Federal de Uberlândia, Rodovia LMG 746, Km 1 Instituto de Geociências e Ciências Exatas Departamento de Geologia Aplicada Universidade Estadual Paulista/UNESP, Avenida 24-A, Bela Vista, 178 Instituto de Biociências Departamento de Zoologia Universidade Estadual Paulista/UNESP, Distrito de Rubião Junior s/n, 510 Instituto de Geociências e Ciências Exatas Departamento de Geologia Aplicada Universidade Estadual Paulista/UNESP, Avenida 24-A, Bela Vista, 178 Petrobras: 0050.0023165.06.6 CNPq: 152385/2016-9 FAPESP: 2014/27337-8 FAPESP: 2017/20803-1 CNPq: 30017/2015-3 CNPq: 401039/2014-5 CNPq: 444070/2014-1

Made available in DSpace on 2018-11-26T16:48:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-10-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) The Late Permian sedimentary succession of the Parana Basin, southern Brazil, provide a valuable source of information about sediment provenance, tectonic processes and, consequently, the paleogeography of the southwestern Gondwana supercontinent. In order to understand the patterns of sedimentary dispersal and reconstruct the Late Permian source-to-sink dynamic, we report a complete series of U-Pb ages and Hf isotopic compositions of detrital zircons from the Rio do Rasto Formation sandstones allied with detailed paleocurrent and sedimentologic data. Our integrated provenance study reveals a consistent sediment transport from the south to the north and northwest. According to the evaluation of zircon ages and Hf isotopes, it was possible to determine four distinct source areas: (i) a distant Late Paleozoic active magmatic arc located in the southwestern Gondwana margin (i.e. Gondwanides Orogen), corresponding to the North Patagonian Massif; (ii) recycling of orthoquartzites from the uplifted Paleozoic Ventania Fold Belt and immature sandstones from the Claromeco Foreland Basin in central eastern Argentina and the Silurian-Devonian successions of the southern Parana Basin (central-northern Uruguay) and North Patagonian Massif; (iii) exhumed areas of the Archean-Paleoproterozoic basement and Neoproterozoic to Early Paleozoic mobile belts of the Damara in southwestern Africa and Ribeira Fold Belt in Uruguay and southern Brazil; and (iv) southeastward provenance of Grenvillian (1.2-1.0 Ga) zircons coming from the mafic to intermediate Mesoproterozoic igneous units of the Namaqua-Natal Belt in South Africa and Namibia. These data allow us to argue that sediments deposited in the Parana Basin during the Late Permian come from both short- and long-distance source areas. In this context, an important population of Permian detrital zircons comes from the Gondwanides Orogen in the south, probably carried by transcontinental alluvial systems. Close to the source area, antecedent river channels would have eroded older sedimentary rocks of the Ventania Fold Belt, Claromeco and Chaco-Parana basins and North Patagonian Massif, crosscutting a peripheral bulge and flowing towards the alluvial plain of the intraplate setting to areas further north. Concomitantly, these sediments are reworked by strong winds that even helped carrying the grains to the Parana Basin depositional site. (C) 2016 Elsevier Ltd. All rights reserved. Univ Sao Paulo, Inst Geociencias, Rua Lago 562,Cidade Univ, BR-05508080 Sao Paulo, SP, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24-A, BR-13506900 Rio Claro, SP, Brazil Univ Fed Ouro Preto, Escola Minas, Dept Geol, BR-35400000 Ouro Preto, MG, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Ave 24-A, BR-13506900 Rio Claro, SP, Brazil CNPq: 142202/2013-4 CNPq: 300423/89-9 CNPq: 308563/2013-1 FAPEMIG: CRA RDP-00063/10 FAPEMIG: APQ03943 FAPEMIG: RDP 0067-10

Made available in DSpace on 2018-12-11T17:28:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-07-15 The Araripe Basin, located in northeastern Brazil, originated during the Gondwana continental break-up responsible for the opening of the South Atlantic during the Early Cretaceous. In the Araripe Basin, the post-rift Aptian sequence corresponds to the Santana Group, which is composed, in upward succession, of mostly clastic continental and rare carbonate layers of the Barbalha, Crato, Ipubi and Romualdo Formations. The laminated limestones of the Crato Formation were deposited in a lacustrine environment preceding the deposition of the Ipubi Formation evaporites. They are age-equivalent to the limestones of the pre-salt interval of the east coast of Brazil, which contains large petroleum reserves. The excellent preservation of its macrofossils has made the Crato Formation known worldwide as a Fossil Lagerstätte. The limestones are macroscopically homogeneous, and their deposition has been previously attributed to chemical precipitation. Although the carbonate laminites are macroscopically undifferentiated, mineralogical variations, microscopic texture and distinctive biotic aspects supported the characterization of four microfacies: planar laminated, crustiform, nodular and rhythmic. The microfacies analysis indicated a strong and pervasive biological activity in the Crato limestone morphogenesis. Organominerals precipitated by the metabolic action of cyanobacteria and/or sulfate-reducing bacteria and methanogenic-oxidizing archea are represented by calcite and pyrite. Calcified coccoid and filaments are common, furthermore, the presence of calcified biofilms composed of exopolymeric substances (EPS) is ubiquitous. The presence of amorphous organic matter (AOM) and gypsum, particularly in the rhythmic microfacies, indicates anoxic/dysoxic conditions and stressful environments during periods of drought and low lake levels which favored the development and preservation of microbial biofilms. Phytoclasts and miospores when present in the succession indicate an extrabasinal contribution during wetter periods, although the environment remained of very low energy. The evidence of microbial influence in the formation of the laminated limestones of the Crato Formation is of great importance for understanding the excellent preservation of the unit's fossils and for modeling the evolution of the Aptian carbonate sequences in Brazil. Petrobras — Petroleo Brasileiro S.A., Avenida Chile UNESP — Universidade Estadual Paulista Instituto de Geociencias e Ciencias Exatas, Avenida 24A UNESP — Universidade Estadual Paulista Instituto de Geociencias e Ciencias Exatas, Avenida 24A

Made available in DSpace on 2020-12-12T01:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The Ediacaran-Cambrian Bambuí Group in Brazil records an anomalously positive excursion in carbonate carbon isotopes (δ13Ccarb) with a sustained plateau of ca. +15‰ (aka the Middle Bambuí Excursion–MIBE). Considering that the δ13Ccarb signals in Ediacaran-Cambrian seawaters do not typically exceed +6‰, the MIBE therefore represents a profound carbon cycle anomaly in Earth's history. Although intensive studies have been done on the Bambuí Group, origins of the MIBE remain enigmatic. In order to better constrain the biogeochemical carbon and sulfur cycles during the MIBE, high-resolution chemostratigraphic analysis was conducted for both the plateau (i.e., Lagoa do Jacaré Formation) and the recovery part (i.e., lower Serra da Saudade Formation) of the MIBE. Chemostratigraphic profiles reveal remarkably different values in δ13Ccarb, δ13Corg, δ18Ocarb, and δ34Spyrite between these two studied MIBE intervals. The new data show that the plateau of the MIBE is characterized by coupled higher δ13Ccarb, higher δ13Corg, and higher δ34Spyrite signals compared with the recovery part of the MIBE. Based on multiple lines of sedimentological, geochemical, and model evidence, we propose that the possibilities of enhanced organic carbon burial and porewater methanogenesis are insufficient to explain the MIBE. Instead, local or regional controlling factors, including water-column methanogenesis, low-sulfate conditions, and enhanced carbonate recycling in a restricted basin may have played a role, independently or in unison, in generating this profound positive δ13Ccarb excursion. Therefore, the MIBE may reflect a regional event, instead of a global carbon cycle anomaly. We caution against the use of the MIBE in chemostratigraphic correlations on a global scale or any other attempt to infer global carbon cycling at that time. The biogeochemical landscape of the late Ediacaran-Cambrian basins and ocean margins may be more heterogeneous than previously thought. Analytical Environmental and Geo- Chemistry Group Vrije Universiteit Brussel ET-HOME (Evolution and Tracers of the Habitability of Mars and Earth) Astrobiology Research Consortium Department of Geology Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) Centro de Pesquisas Manoel Teixeira da Costa Instituto de Geociências Universidade Federal de Minas Gerais, Pampulha Department of Geological Sciences University of North Carolina Hydrology and Remote Sensing Laboratory Beltsville Agricultural Research Center US Department of Agriculture Department of Geology Faculty of Engineering University of Mons State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation School of Geoscience and Technology Southwest Petroleum University Department of Geology Institute of Geosciences and Exact Sciences São Paulo State University (Unesp) CNPq: CNPq-486416/2006-2

Made available in DSpace on 2020-12-12T01:22:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Petrobras Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Syneclises are long-lived sedimentary basins characterized by complex subsidence and erosion histories. The premise that these geotectonic units evolve from initial rifting processes following thermal (or flexural) subsidence is widespread in the geologic sciences and, to this day, remains a controversial issue. Seeking to test this hypothesis, we proceeded a novel multi-proxy provenance study aiming to identify differences (and/or similarities) in the sedimentary signal and source areas of the Jaibaras (rift) and Parnaíba (sag) basins. We conducted a detailed analysis of trace elements geochemistry of detrital rutile grains, macroscopic gravel composition and paleocurrents from the sedimentary deposits of the Aprazível Formation (Ediacaran - Cambrian, top of Jaibaras Basin) and the Ipu Formation (Ordovician, basal unit of Parnaíba Basin). Our data reveal that important changes in source areas occurred between the end of the rifting and the beginning of the sag phase, reinforcing the hypothesis that the evolution of the Jaibaras and Parnaíba basins were not genetically related. Our results demonstrate that conglomerates of the rift sequence are predominantly composed of volcanic, sedimentary, and metamorphic angular to sub-angular clasts, pointing to diverse, nearby source areas. Contrastingly, conglomerates of the initial sag sequence have greater sedimentary maturity, with dominant rounded vein quartz clasts and other minor source contributions, which suggest distant source areas, showing a consistent paleocurrent direction towards NW. Indeed, the detrital rutile trace elements geochemistry demonstrates that the source areas of these two units were distinct, revealing an important decrease in the input of granulite facies and metamafic grains in the sag basin comparing with the rift succession. In conclusion, as well as paleomagnetic and geochronological studies, the provenance methods using a multi-proxy approach proved to be an effective and powerful technique for distinguishing modifications in the sedimentary signal between rift-to-sag sequences. Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24-A, Bela Vista, 178 Instituto LAMIR Universidade Federal do Paraná Centro Politécnico, Jardim das Américas Departamento de Geologia Escola de Minas Universidade Federal de Ouro Preto Campus Morro do Cruzeiro Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Avenida 24-A, Bela Vista, 178 Petrobras: 2014/00519–9 FAPESP: 2017/19550-1

Made available in DSpace on 2019-10-04T12:36:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Discoidal sedimentary structures are commonly described in Proterozoic strata, and even more common in Ediacaran to lower Cambrian sedimentary successions. Many abiotic processes are able to produce such circular or discoidal structures in bedding planes, however, their abundance in Ediacaran strata suggests a possible correlation with the evolution and preservation of epibenthic metazoans that emerged at the end of this period. In the South American paleontological record, studies regarding the Ediacaran soft-bodied organisms are meager and restricted to few reports in Brazil, Paraguay, and Argentina. In many cases, such fossils were only tentatively characterized in terms of their general morphology and putative taxonomic affinity. Thus, considering the almost absence of work on these enigmatic structures in South America, this paper aims to make a critical analysis on the main occurrences of Ediacaran-Cambrian discoidal structures described in this continent. Based on a detailed review and unpublished data, it was possible to provide a general picture concerning the main paleoenvironmental and sedimentary significance of this structures, as well as on the most promising prospects in terms of the paleontological record of Ediacaran soft-bodied metazoans in South American. In this sense, it was settled that occurrences such as those in the Jaibaras and Itajai basins should be reassessed in order to establish reliable criteria of biogenicity. In the case of the material from the Sete Lagoas and Tagatiya Guazu formations, it is considered more parsimonious to interpret the discoidal features as resulting from microbial processes. Similarly, the discoidal structures of the Cerro Negro Formation presents a series of internal laminations and textures that resembles those developed by processes of microbial grain binding and trapping suggesting that, at least part of this material, can be related to microbially induced sedimentary structures. Finally, for the ichnologically diversified Puncoviscana and Camaqua basins, two different scenarios were identified. The first presents an ichnological assemblage strongly indicative of lower Paleozoic, and possibly Cambrian affinity. Thus, the discs in association with these traces, should be viewed with caution and interpretations made in light of a Paleozoic context. The second possesses an ichnological association typical of that expected for the Ediacaran-Cambrian transition, and the diversity of discoidal forms can potentially represent imprints of macroorganisms on a microbially bounded substrate, thus deserving a more detailed approach. Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil Univ Fed Sao Paulo, Dept Ecol & Biol Evolut, Rua Prof Artur Riedel,275, BR-09972270 Diadema, Brazil UNLP CONICET, Ctr Invest Geol, Calle 1,644, RA-1900 La Plata, Buenos Aires, Argentina Univ Vale Rio Sinos UNISINOS, Programa Posgrad Geol, Sao Leopoldo, RS, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Ave 24A,1515, BR-13506900 Rio Claro, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618000 Botucatu, SP, Brazil CNPq: 444070/2014-1 FAPESP: 2015/24608-3