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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 2022-04-28T19:45:46Z (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 2021-06-25T15:02:23Z (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

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 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

Brazil is a natural laboratory for the application of isotope stratigraphy tools on the study of Precambrian sedimentary successions, with excellent registers of Archean, Paleo, Meso, and Neoproterozoic age. Those successions witnessed the most extreme and unidirectional events in Earth's history, such as the Paleoproterozoic and Neoproterozoic oxygenation events (GOE and NOE), the main stages of iron formation deposition, the global Cryogenian glaciations and the explosive diversification of metazoans near the Precambrian/Cambrian border. Chemical sedimentary rocks such as carbonates, iron formations and evaporites that can act as natural recorders of seawater composition are present in all of those successions and furnish important pieces of evidence in order to reconstruct the chemostratigraphic record. The field of isotope stratigraphy keeps expanding in Brazil and novel information from developing isotopic systems will surely add to the growing database and provide important information on Earth's ancient biogeochemical cycles in the years to come.

Made available in DSpace on 2020-12-11T03:29:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01. Added 1 bitstream(s) on 2021-07-15T15:25:14Z : No. of bitstreams: 1 S2317-48892019000300309.pdf: 48648629 bytes, checksum: 62cde2d360f0b6cc9622a6b164627386 (MD5) Petrobras Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Sedimentologic and stratigraphic studies of paleo-deserts from the Brazilian Cretaceous are of great potential to understand the paleoclimate and paleogeography of Gondwana during its final rifting stage. Herein, we describe and discuss two depositional units characterized by two distinct eolian systems that are bounded by a long-lived unconformity. The Lower Unit (Barremian/Aptian) encompasses a wet eolian system composed of dune, interdunes, and ephemeral alluvial deposits. A continuous paleosol horizon in the upper part of the Lower Unit records dune stabilization and end of eolian accumulation, in a period of climate amelioration possibly in the late Aptian. The stratigraphic gap proposed for the unconformity (Cenomanian to Coniacian) coincides with the Cretaceous Thermal Maximum. The Upper Unit (Santonian?/ Campanian) comprises dune fields of a dry eolian system capped by the Mata da Corda volcanic rocks. Cross stratification dip directions from both eolian systems shows transport towards SSW. Paleo-winds coming from the northeast quadrant reveal that the continental breakup and drifting had little influence on the surface winds in this Gondwana sector. The Upper Cretaceous paleo-winds are coherent with global paleo-circulation models, based on a high-pressure cell over the South Atlantic proto-ocean, favoring desertification in the inner portion of the southwestern Gondwana. Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Rio Claro, SP, Brazil Univ Estadual Campinas, Inst Geociencias, Campinas, SP, Brazil Univ Sao Paulo, Inst Geociencias, Sao Paulo, SP, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Rio Claro, SP, Brazil Petrobras: 2014/00519-9

Made available in DSpace on 2018-11-26T16:18:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The basal portion of the Permian Rio do Rasto Formation (Serrinha Member), Passa Dois Group, Parana Basin, Brazil, records an entirely new bivalve fauna intercalated between the underlying Pinzonella neotropica assemblage (uppermost portion of the Teresina Formation) and the overlying Leinzia similis assemblage (Rio do Rasto Formation). Mollusks of these assemblages lived in marginal shallow-water habitats of an immense epeiric sea and were dominated by endemic bivalve species. Taxonomic analysis revealed the presence of Terraia curvata (60.61%), Astartellopsis prosoclina (19.70%), Cowperesia emerita (10.61%), Leinzia curta (4.55%), Terraia bipleura (3.03%) and Beurlenella elongatella (1.52%), which are associated with conchostracans and plant remains. Species composition, abundance, and dominance in this novel assemblage differ notably from the preceding ones, suggesting a substantial evolutionary turnover. Regional-scale environmental changes recognized based on taphonomy, facies analysis, and geochemical data consist of progressive freshening of the marginal habitats of the Parana Basin and taxic changes that include the following: (a) loss of genera, (b) decrease in bivalve abundance and ecological guilds, (c) disappearance of the dominant bivalve group (Pinzonellinae) and (d) diversification of Terrainae bivalves. The ecological signature also changed notably because only infaunal suspension-feeding bivalves are present, indicating a significant loss of functional diversity at the regional scale. Likely stressor factors (among others) are tied to freshening events, suggesting profound changes in (a) salinity, (b) primary productivity and (c) a lack of coarse, stable substrates coupled with high bioturbation rates. Hence, our regional example could offer valuable clues to benthic (bivalve) community responses in a habitat subjected to (a) rapid climate changes and (b) freshening events in shallow-water settings. Finally, the stratigraphic range of the dominant species (T curvata) appears to be restricted to the basal portion of the Rio do Rasto Formation. Based on the presence of this species and of C. emerita, the novel assemblage is tentatively correlated with that of the Permian Gal-As Formation in the Huab region of Namibia, thus supporting previous assumptions of a seaway connecting both basins during the Guadalupian Epoch. (C) 2015 Elsevier Ltd. All rights reserved. Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618970 Botucatu, SP, Brazil Univ Sao Paulo, Programa Posgrad Geoquim & Geotecton, Inst Geociencias, BR-05508080 Sao Paulo, SP, Brazil Univ Sao Paulo, Dept Geol Sedimentar & Ambiental, Inst Geociencias, BR-05508080 Sao Paulo, SP, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618970 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, Brazil FAPESP: 2011/01975-0 CNPq: 500694/92-3 CNPq: 151853/2008-8

The Permian Serra Alta Formation was generated under transgressive conditions within a large, calm epeiric sea. A monotonous succession of ‘barren’, massive mudstones deposited under oxygen-deficient conditions (mainly below storm wave base) is the main lithofacies of this unit. Fossils are generally rare and diluted in the matrix, but certain intervals contain shell-rich concentrations with well-preserved, closed articulated bivalves, mixed with shells and comminuted debris with variable quality of preservation, all encased in carbonate concretions. Two main scenarios may account for the origin of these bivalve-rich concretions (i.e. unique events in sea-water chemistry or unique burial-starvation couplets). Sedimentological and taphonomic information indicates that the final deposition of the original shell-rich mudstone intervals was probably tied to episodic influx of fine-grained sediments in distal settings. Moderate bioturbation is also recorded suggesting low rates of sedimentation prior to early diagenesis. Hence, the fossil concentrations in concretions were formed due to the interplay of event and background sedimentation. These are internally simple concentrations with complex depositional histories. The concretion-bearing beds are not randomly distributed in the Serra Alta Formation. Rather, they are found in the sparsely fossiliferous offshore deposits of the basal to intermediate portions of the unit. Thus, the concretionary mudstone beds and associated deposits are preserved in particular intervals and can be tracked for kilometres. This indicates that the conditions essential for concretion development existed only at particular stratigraphical intervals. Finally, our study strongly corroborates the idea that concretions are critical sources of sedimentological, taphonomic and stratigraphical information.

During the Ediacaran the Clymene Ocean separated the Lau-rentia, Amazonia, and Rio Apa cratons from several landmasses to the west forming the proto-Gondwana supercontinent. However, no clear evidence about the existence of Ediacaran epeiric seas over those landmasses has been found. Here we report and discuss the discovery of the Ediacaran guide fossil Cloudina sp. associated with other metazoan body and trace fossils in the Bambui Group (central eastern Brazil). The Ediacaran age of the Bambui Group and the paleogeographic position of Cloudina -bearing successions in Brazil, Antarctica, Namibia, and Argentina suggest a scenario of ocean con-nectivity among coeval intracratonic basins of South America, Africa, and Antarctica at the end of Neoproterozoic time. The new fi nding epitomizes one of the most important paleontological discoveries ever made in South America, helping to solve an old paleogeographic puz-zle of the Gondwana supercontinent.INTRODUCTION The Bambui Group crops out in central eastern Brazil, and is one of the most studied Neoproterozoic sedimentary successions in South America. It comprises an extensive, fl at-lying cratonic cover in erosional contact with Paleoproterozoic and Archean basement rocks of the Sao Francisco craton. In its eastern and westernmost occurrences, the Bam-bui Group is deformed and metamorphosed by the Brasilia and Aracuai mobile belts, respectively (Fig. 1A). The regional tectonostratigraphy has been interpreted as refl ecting deposition in a foreland basin related to Gondwanan collisions involving the Sao Francisco craton (Pimentel et al., 2011).The Bambui Group (BG) overlies rocks of the Macaubas Group and Jequitai Formation and the Carrancas conglomerate, units supposedly de-posited during Sturtian glaciation. The unit is 700–1000 m thick (Misi et al., 2007) and comprises limestones and dolomites of the Sete Lagoas For-mation at the base that grade upward to shales and siltstones of the Serra de Santa Helena Formation, followed by marls, siltstones, limestones, and sandstones of the Lagoa do Jacare, Serra da Saudade, and Tres Marias Formations (Fig. 1B).The precise age of the BG is not well established, precluding accurate correlation with other supposedly coeval successions such as the Corumba Group (Brazil), Itapucumi (Paraguay), Arroyo del Soldado (Uruguay), Si-erras Bayas (Argentina), and Nama Group (Namibia). The presence of

La asociación fósil de la Formación de Tagatiya Guazu (Grupo ediacárico de Itapucumi, Paraguay) representa una oportunidad única para investigar los parámetros paleoecológicos y contribuir con información taxonómica sobre las asociaciones de Cloudina en Gondwana SW.

Shell bed levels in the Low Head Member of the early Oligocene Polonez Cove Formation at King George Island, West Antarctica, are re-interpreted based on sedimentological and taphonomic data. The highly fossiliferous Polonez Cove Formation is characterized by basal coastal marine sandstones, overlain by conglomerates and breccias deposited in fan-delta systems. The shell beds are mainly composed of pectinid bivalve shells of Leoclunipecten gazdzickii and occur in the basal portion of the Low Head Member. Three main episodes of bioclastic deposition are recorded. Although these shell beds were previously interpreted as shelly tempestites, we present an alternative explanation: the low fragmentation rates and low size sorting of the bioclasts resulted from winnowing due to tidal currents (background or diurnal condition) in the original bivalve habitat. The final deposition (episodic condition) was associated with subaqueous gravity driven flows. This new interpretation fits with the scenario of a prograding fan-delta front, which transported shell accumulations for short distances near the depositional site, possibly between fair-weather and storm wave bases. This work raises the notion that not every shell bed with similar sedimentological and taphonomic features (such as geometry, basal contact, degree of packing and shell orientation in the matrix) is made in the same way.

The emergence of soft-bodied metazoans and the radiation of the earliest skeletal organisms substantially changed the ecological dynamics of Ediacaran environments, leading to the genesis of biogenic hard-part deposits for the first time in Earth’s history. The impact of bioclast origin on sedimentary processes is analyzed herein, focusing on the sedimentology and taphonomy of shell concentrations dominated by the Ediacaran index fossil Cloudina from the Itapucumi Group, Paraguay. Skeletal concentrations include both dense accumulations of parautochthonous, disarticulated specimens (“Type 1 deposits”) and in situ specimens preserved as loosely packed assemblages (“Type 2 deposits”). At that time, Cloudina was the critical source of durable biomineralized hard parts in an environment nearly free of other bioclasts. The simple fabric and geometry of these accumulations are typical of Cambrian-style shell beds. Despite their Precambrian age, these deposits indicate that the establishment of the Phanerozoic style of marine substrates and preservation in early shell beds was determined more by the acquisition of hard parts than by environmental changes.

Made available in DSpace on 2018-11-26T17:35:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This is the first record of a Permian seep deposit and an associated, morphologically bizarre, bivalve-dominated fauna from the Passa Dois Group, Parana Basin, Brazil. Shales of the outer-shelf facies of the Serra Alta Formation preserve a low-diversity but high-abundant, large-sized bivalve fauna with unusual morphologies inside discoidal carbonate concretions. The bivalves are about ten times larger than tiny bivalves found scattered in laterally equivalent mudstones of the same unit. Intercalated between two concretion-bearing horizons, a cm-thick, sheet-like, disrupted, brecciated, partially silicified carbonate layer with microbially-induced lamination is recorded. In some areas, the carbonate layer shows vertical structures formed by injections of mud mixed with white limestone clasts and microbial linings. Immediately above this, silicified mudstones preserve small domal structures (= mounds) with a slightly depressed center. Monospecific concentrations of closed articulated shells of Tambaquyra camargoi occur at the base of these domes. Carbon-isotope (delta C-13) values from the shells, brecciated carbonates, and fossil-rich concretions are all depleted (negative values similar to -6.1 to -7.6 parts per thousand). Combined taphonomic, sedimentological, petrographic, geochemical and paleontological data suggest that the disrupted, brecciated carbonate and associated fauna and domes may have formed by an exudation system. Indeed, this interval of the Serra Alta Formation is similar to 8.7 m above the contact with the underlying, oil-rich Irati Formation. This unit has very high total organic carbon (up to 23%) values and high sulphur contents, supporting the interpretation of the lithological and paleontological features as result of seepage of organic compounds at the seafloor. Where the gases and hydrocarbons escaped, the seabed was colonized by, at least facultatively, chemosymbiotic bivalves. The species above belong to a highly endemic group of pachydomids that were shallow infaunal bivalves (SIB). Hence, they are not related to classical bivalves with extant representatives, which are chemosymbionts. This may reflect an extreme adaptive radiation and repopulation of anoxic-dysoxic bottoms of the Parana Basin by SIB species. (C) 2017 Elsevier Ltd. All rights reserved. Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618970 Botucatu, SP, Brazil Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Campus Rio Claro, BR-13506900 Rio Claro, SP, Brazil Friedrich August Univ Erlangen Nurnberg, FG Palaoumwelt, GeoZentrum Nordbayern, Loewenichstr, D-91054 Erlangen, Germany Univ Sao Paulo, Inst Energia & Ambiente, Sao Paulo, SP, Brazil Univ Sao Paulo, Inst Geociencias, Sao Paulo, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, BR-18618970 Botucatu, SP, Brazil Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Dept Geol Aplicada, Campus Rio Claro, BR-13506900 Rio Claro, SP, Brazil FAPESP: 96/09708-9 FAPESP: 12/12508-6 CNPq: 302903/12-3 CNPq: 401039/2014-5

Made available in DSpace on 2018-11-26T17:34:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-01 The publication of the comments by Vesely & Schemiko (Comment on From source-to-sink: The Late Permian SW Gondwana paleogeography and sedimentary dispersion unraveled by a multi-proxy analysis by L. Alessandretti, R. Machado, L.V. Warren, M.L. Assine and C. Lana [Journal of South American Earth Sciences 70 (2016) 368-382], Journal of South American Earth Sciences, this issue) on our paper entitled From source-to-sink: The Late Permian SW Gondwana paleogeography and sedimentary dispersion unraveled by a multi -proxy analysis (L. Alessandretti, R. Machado, L.V. Warren, M.L. Assine and C. Lana (Journal of South American Earth Sciences 70 (2016) 368-382) provides a worthy opportunity to further clarify our observations and interpretations regarding the provenance of the Late Permian Rio do Rasto Formation and its implications on SW Gondwana paleogeography and sedimentary dispersion. (C) 2017 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 Conselho Nacl Desenvolvimento Cientif & Tecnol, Brasilia, DF, 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

The intriguing Ediacaran fossil Namacalathus is described from limestones of the Tagatiya Guazú Formation, Itapucumi Group, Paraguay. This is the fifth occurrence of the genus in the Ediacaran geological record. The Paraguayan Namacalathus specimens are preserved as partially complete spheroidal cups with an opening at the top and thin walled stems. The remains of this soft-calcified globe-shaped organism occur as sparse disarticulated parautochthonous fragments within bioclastic deposits dominated by Cloudina shells with subordinate Corumbella fragments. The co-occurrence of these three skeletal metazoan species in the same environmental context attests that the diversity of the Paraguayan accumulations is ecologically comparable to the typical skeletal assemblage of the Nama Group. The discovery of new samples of Namacalathus in the Itapucumi Group also indicates that this genus presented a broader paleobiogeographic distribution than previously thought and, in the same way as Cloudina, it represents a low latitude, shallow water metazoan of the Ediacaran Gondwana., Centro de Investigaciones Geológicas

The origin, affinity and paleoecology of macrofossils of soft-bodied organisms of the terminal Ediacaran Period have been highly debated. Previous discoveries in South America are restricted to small shelly metazoans of the Nama Assemblage. Here we report for the first time the occurrence of discoidal structures from the Upper Ediacaran Cerro Negro Formation, La Providencia Group, Argentina. Specimens are preserved in tabular sandstones with microbially-induced sedimentary structures. Flute marks and linear scours at the base of the sandstone layers indicate deposition under high energy, episodic flows. Stratigraphic, sedimentologic, petrographic and taphonomic analyses indicate that the origin of these structures is not related to abiotic process. Preservational and morphological features, as invagination and the presence of radial grooves, indicate that they resemble typical morphs of the Aspidella plexus. The large number of small-sized individuals and the wide range of size classes with skewed distribution suggest that they lived in high-density communities. The presence of Aspidella in the Cerro Negro Formation would represent the first reliable record of Ediacaran soft-bodied organisms in South America. It also supports the paleogeographic scenario of the Clymene Ocean, in which a shallow sea covered part of the southwest Gondwana at the end of the Ediacaran., Facultad de Ciencias Naturales y Museo, Centro de Investigaciones Geológicas

Terra Nova, 23, 382–389, 2011 Abstract An in situ assemblage of Cloudina, thrombolites and an ichnofossil (cf. Archaeonassa), together with fragments of Corumbella werneri, is reported here, from a tidally influenced, shallow, lagoonal setting on a carbonate ramp within the Itapucumi Group, Paraguay. The association of Cloudina with thrombolites is comparable to other terminal Neoproterozoic occurrences, but the coexistence of shelly fossils in situ with trace fossils and microbially induced sedimentary structures is apparently unique. This discovery extends the record of Cloudina and Corumbella in South America and further elucidates the diversity, distribution and palaeoecology of shelled organisms in late Ediacaran time.

The Neoproterozoic (Ediacaran) Itapucumi Group in northern Paraguay is composed of carbonate and siliciclastic rocks, including ooid grainstones, marls, shales and sandstones, containing Cloudina fossils in the eastern region. It is almost undeformed over the Rio Apa Cratonic Block but shows a strong deformational pattern at its western edge. A detailed structural analysis of the Itapucumi Group was conducted in the Vallemi Mine, along with a regional survey in other outcrops downstream in the Paraguay River and in the San Alfredo, Cerro Paiva and Sargento Jose E. Lopez regions. In the main Vallemi quarry, the structural style is characterized by an axial-plane slaty cleavage in open to isoclinal folds, sometimes overturned, associated with N–S trending thrust faults and shear zones of E-vergence and with a low-grade chlorite zone metamorphism. The structural data presented here are compatible with the hypothesis of a newly recognized mobile belt on the western side of the Rio Apa Cratonic Block, with opposite vergence to that of the Paraguay Mobile Belt in Brazil. Both belts are related to the Late Brasiliano/Pan-African tectonic cycle with a Lower Cambrian deformation and metamorphism age. The deformation could be due to the late collision of the Amazonian Craton with the remainder of Western Gondwana or to the western active plate boundary related to the Pampean Belt. The structural and lithologic differences between the western Itapucumi Group in the Vallemi and Paraguay River region and the eastern region, near San Alfredo and Cerro Paiva, suggest that this group could be divided into two lithostratigraphic units, but more stratigraphic and geochronological analyses are required to confirm this possibility.

Made available in DSpace on 2018-11-27T20:01:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-01 Petrobras Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Center for Geosciences Applied to Petroleum Geology - UNESPetro, IGCE/Unesp/Rio Claro Training of Human Resources in Petroleum Geology Program - UNESP The evolution of the Cretaceous basins of the Brazilian northeastern hinterland was associated with the Gondwana rifting and opening of the South Atlantic Ocean. The first marine ingression in northeastern Brazil occurred in the late Aptian and was recorded as the Santana Group of the Araripe Basin, which is currently an isolated basin, located hundreds of kilometers away from the Brazilian marginal basins. Bellow the first upper Aptian marine deposits, an important section of fossiliferous limestone (Lagerstatte) was deposited and preserved in the Crato Formation transitioning upward into evaporites of the Ipubi Formation. The direction of the marine ingression is controversial, with several possibilities being suggested, mainly due to the absence of other areas of upper Aptian marine sections within the hinterland. Serra do Tona is a sedimentary mesa with scarped edges where the upper part of the Marizal Formation crops out, displaying laminated limestones, litho-and chrono-correlated with those of the Crato Formation, is preserved. Therefore, this mixed upper Aptian section, at the North Tucano Basin (Serra do Tona), is a unique occurrence of utmost importance to the definition of sedimentary events and paleogeographical reconstruction of northeastern Brazil during the late Aptian. A detailed stratigraphic analysis allowed the definition and characterization of two upper Aptian depositional sequences bounded by regional disconformities. Both sequences are dominantly transgressive and carbonatesiliciclastic in composition. The lower sequence comprises the basal portion of the Marizal Formation and consists of a succession of fluvial sandstones, ending on a laterally continuous thin interval (

Made available in DSpace on 2018-11-26T17:06:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) During the late Paleozoic, the intracratonic Parana Basin, Brazil, in central Gondwanaland, was covered by a huge (>1.600.000 km(2)), shallow and isolated epeiric sea. Within the Permian succession, oxygen deficient fades are commonly recorded in the Mesosaurus-bearing Irati Formation (Cisuralian, Artinskian/Kungurian) and the overlaying Serra Alta Formation (Guadalupian, Wordian/Capitanian). Barren, dark-grey mudstones are the main facies preserved in this last unit, which has usually discouraged extensive and detailed stratigraphical and paleontological investigations. However, exhaustive sedimentological, taphonomic and paleontological surveys in those deposits reveal a dynamic and complex depositonal history. Based on sedimentary fabric, autochthonous to parautochthonous occurrences of shelly benthic invertebrates (bivalves) and the presence/absence of concretion-bearing and phosphate rich layers, we report variations in the oxygen levels of bottom and pore waters, in bathymetry, sedimentation rates, and changes in benthic colonization. Our data indicate that the deposition of this apparently barren mudstone-dominated succession was driven by a complex interplay of variations in sedimentation rate and oxygen pulses tied to tectonic and climate changes. Three distinct populations or invertebrate paleocommunities were recorded, which were adapted to (a) normal background lowoxygerr (dysoxic) conditions (i.e., minute infaunal suspension-feeding bivalves associated with the trace fossil Planolites), (b) chemically toxic (anoxic/extreme dysoxic) substrates, including gigantic burrowing bivalves (probable chemosymbiotic taxa), and (c) oxic/dysoxic substrates following short-term bottom disruptions. (C) 2016 Elsevier Ltd. All rights reserved. Univ Estadual Paulista, Dept Zool, Inst Biociencias, Postal Code 510, BR-18618970 Botucatu, SP, Brazil Univ Sao Paulo, Inst Geociencias, Programa Posgrad Geoquim & Geotecton, BR-05508080 Sao Paulo, SP, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Campus Rio Claro,Postal Code 178, BR-13506900 Rio Claro, SP, Brazil Univ Sao Paulo, Inst Energia & Ambiente, Sao Paulo, SP, Brazil Univ Sao Paulo, Inst Geociencias, Sao Paulo, SP, Brazil Univ Estadual Paulista, Dept Zool, Inst Biociencias, Postal Code 510, BR-18618970 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Geol Aplicada, Inst Geociencias & Ciencias Exatas, Campus Rio Claro,Postal Code 178, BR-13506900 Rio Claro, SP, Brazil FAPESP: 2012/12508-6 CNPq: 302903/2012-7 CNPq: 303020/2015-6 CNPq: 444070/2014-1

* ABsTrACT environmental changes occurred in southern hemisphere in response to the separation of Antarctica from Australia, around eocene/ oligocene boundary, and from south America, during the late oligocene, greatly affected biodiversity in southern ocean. Although it is generally accepted that the Antarctic thermal isolation affected the Cenozoic biodiversity by changing environmental conditions, there is no available study concerning the Cenozoic dynamics of Antarctic bivalve diversity in relation to climatic changes. in this study, an assembling of all available bivalve family and genera described from Antarctic Cenozoic deposits as well as modern bivalve family and genera were analyzed in order to evaluate possible effects of Cenozoic environmental changes on Antarctic bivalve diversity along the Cenozoic. The main conclusion of this work is that the currently known Cenozoic record of the Antarctic bivalves does not reflect Cenozoic environmental changes. This is probably related to the restricted record of Antarctic bivalves, and therefore to the scarce knowledge on the Cenozoic diversity of the group. The analysis also revealed that Cenozoic intervals of highest diversity are attributed to few areas in Antarctica that are available for paleontological exploration. Besides, the large number of recorded bivalve taxa in some Cenozoic intervals may be related to the stratigraphic control of deposits.

What is an inlier sedimentary basin? What are the main mechanisms of sedimentary infilling? How do the depositional systems behave? And last, but certainly not the least, what geological events occurred in the last million years and continue to take place in the Pantanal area today? These issues are considered in this chapter, based on available geological, geomorphological, and geochronological datasets. The Pantanal is an active sedimentary basin with numerous faults and associated earthquakes. Movements along these faults cause subsidence on blocks within the basin, generating depressions that are highly susceptible to flooding, and also create accommodation space for sediment storage. One hypothesis on the origin of the Pantanal Basin relates the processes of subsidence with tectonic activity in the Andean orogen and foreland system during the Quaternary. Alternatively, the lack of geochronological data leaves open the possibility that the basin formed much earlier, perhaps during an interval of widespread tectonism in Brazil during the Eocene. The modern Pantanal depositional tract is composed of the Paraguay River trunk system, numerous fluvial megafans and interfan floodplains, and thousands of lakes, many of them integral to the Nhecolândia landscape. The Pantanal’s geomorphology is most likely the product of climatic fluctuations and environmental changes that have been occurring since the Late Pleistocene. Relict morphologic features like paleochannels have been preserved on the surfaces of abandoned lobes on several large fluvial megafans. After a period dominated by arid conditions in the Late Pleistocene, the Pantanal area experienced an episode of humidification and increasing fluvial discharge in the Early Holocene. This process promoted important modifications in the extant drainage system, for example, the avulsion of the Paraguay River that caused the Nabileque paleomeander belt to be abandoned. The landscape and sedimentary deposits of Pantanal Basin are “living” geologic records of changing rivers, avulsions, floods, and climate changes that occurred in the last several thousand years. Understanding the dynamics of these transitions is critical for unveiling the geologic history of the world’s largest tropical wetland.

We describe the occurrence of non-marine bivalves in exposures of the Middle Permian (Capitanian) Brenton Loch Formation on the southern shore of Choiseul Sound, East Falklands. The bivalves are associated with ichnofossils and were collected from a bed in the upper part of the formation, within a 25 cm thick interval of dark siltstones and mudstones with planar lamination, overlain by massive sandstones. The shells are articulated, with the valves either splayed open or closed. At the top of the succession, mudstone beds nearly 1.5 m above the bivalve-bearing layers yielded well-preserved Glossopteris sp. cf. G. communis leaf fossils. The closed articulated condition of some shells indicates preservation under high sedimentation rates with low residence time of bioclasts at the sediment/water interface. However, the presence of specimens with splayed shells is usually correlated to the slow decay of the shell ligament in oxygen-deficient bottom waters. The presence of complete carbonized leaves of Glossopteris associated with the bivalve-bearing levels also suggests a possibly dysoxic-anoxic bottom environment. Overall, our data suggest that the bivalves were preserved by abrupt burial, possibly by distal sediment flows into a Brenton Loch lake, and may represent autochthonous to parautochthonous fossil accumulations. The shells resemble those of anthracosiids and are herein assigned to Palaeanodonta sp. aff. P. dubia, a species also found in the Permian succession of the Karoo Basin, South Africa. Our results confirm that (a) the true distributions in space and time of all Permian non-marine (freshwater) bivalves are not yet well known, and (b) there is no evidence for marine conditions in the upper part of the Brenton Loch Formation.

Although the basic morphology of the Ediacaran metazoan Corumbella werneri (the type species of the genus) is well established, little is known about its skeletal tissue. Carbonaceous fragments of this fossil from the Itapucumi Group (Paraguay) reveal details of the ultrastructure of its carapace, providing an unprecedented opportunity to understand a paradigmatic issue of the evolution of skeletogenesis in early metazoans. Corumbella was a sessile predator whose carapace consisted of organic polygonal plates with pores and papillae similar to features observed in some conulariids. Its occurrence with the shelly fossil Cloudina suggests that the acquisition of protective structures in metazoans involved penecontemporaneous processes of biomineralization and secretion of organic walls.

The Jacadigo Group contains one of the largest sedimentary iron and associated manganese deposits of the Neoproterozoic. Despite its great relevance, no detailed sedimentological study concerning the unit has been carried out to date. Here we present detailed sedimentological data and interpretation on depositional systems, system tracts, external controls on basin evolution, basin configuration and regional tectonic setting of the Jacadigo Basin. Six depositional systems were recognized: (I) an alluvial fan system; (II) a siliciclastic lacustrine system; (III) a fan-delta system; (IV) a bedload-dominated river system; (V) an iron formation-dominated lacustrine or marine gulf system; and (VI) a rimmed carbonate platform system. The interpreted depositional systems are related to three tectonic system tracts. The first four depositional systems are mainly made of continental siliciclastics and refer to the rift initiation to early rift climax stage; the lake/gulf system corresponds to the mid to late rift climax stage and the carbonate platform represents the immediate to late post rift stage (Bocaina Formation deposits of the Ediacaran fossil-bearing Corumba Group). The spatial distribution of the depositional systems and associated paleocurrent patterns indicate a WNW-ESE orientation of the master fault zone related to the formation of the Jacadigo Basin. Thus, the iron formations of the Jacadigo Group were deposited in a starved waterbody related to maximum fault displacement and accommodation rates in a restricted continental rift basin. The Fe–Si–Mn source was probably related to hydrothermal plume activity that reached the basin through the fault system during maximum fault displacement phases. Our results also suggest a restricted tectono-sedimentary setting for the type section of the Puga Formation. The Jacadigo Group and the Puga Formation, usually interpreted as glacial deposits, are readdressed here as basin margin gravitational deposits with no necessary relation to glacial processes.