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Chu et al. (2015, Lilliput effect in freshwater ostracods during the Permian–Triassic extinction) reported a sharp decrease of the size of freshwater ostracods through the terrestrial end-Permian extinction (EPE) interval of the Dalongkou Anticline section in Northwest China. The proposed work is however unacceptable because of taxonomic and methodological issues. Most of the identifications are rejected because of too poor preservation and generic misidentifications due to the unawareness of the abundant literature published for years on Permian freshwater ostracods. The proposed analysis of the size of the misidentified genus Darwinula considers the totality of the recovered specimens but is meaningless by ignoring the aspect of the ontogenetic development of ostracods. As a consequence, the observed reduction of size of ostracods could be related to changes in the taphonomic conditions or in the proportions of juveniles under special environmental, which have already been suggested for marine ostracods through the EPE.

Benthonic marine species show a wide range of biological reactions to seawater chemical changes through time, from subtle adjustments to extinction. The Early Toarcian Oceanic Anoxic Event (T-OAE) was recently recognized in the Neuquén Basin, Argentina, confirming its global scope. The event was identified chemostratigraphically on the basis of a relative increase in marine organic carbon and a characteristic negative carbon-isotope excursion (δ13Corg) in bulk rock and fossil wood in the upper Pliensbachian–lower Toarcian interval in the Arroyo Lapa section (Neuquén). Simultaneously with collection of lithological samples, a high-resolution biostratigraphical survey was carried out, and the scarce benthonic fauna was collected in order to check the biotic response to changing marine geochemical conditions. We present here an analysis of size and abundance data from the T-OAE interval in the Neuquén Basin for the dominant bivalve species, the paper-clam Posidonotis cancellata (Leanza), and relate these data to geochemical proxies (%TOC and δ13Corg) obtained at the same locality. The abundance of P. cancellata increased when the rest of the benthos diminished, reaching a maximum at the onset level of the T-OAE, and then decreasing. Size-frequency distributions show a noteworthy lack of juvenile shells. Shell size shows a positive correlation with %TOC in the whole section, though over the T-OAE interval proper, it decreases below the level where the maximum %TOC value is attained and increases above it. Posidonotis cancellata shows features of opportunistic species, such as high tolerance to hypoxia, strong dominance in impoverished environments and a strong dependence on primary productivity, but at the same time had a reproductive strategy more similar to equilibrium species, with relatively low juvenile mortality rates. Several anatomical features suggest adaptation to permanently dysaerobic environments. The species disappeared just before the minimum negative carbon-isotope value was reached; and by the same time the genus became extinct worldwide. Fil: Ros Franch, Sonia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Echevarría, Javier. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Damborenea, Susana Ester. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Manceñido, Miguel Oscar. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Jenkyns, Hugh C.. University of Oxford; Reino Unido Fil: Al Suwaidi, Aisha. Khalifa University Of Science And Technology; Emiratos Arabes Unidos Fil: Hesselbo, Stephen P.. University of Exeter; Reino Unido Fil: Riccardi, Alberto Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina

Charcoal is produced by pyrolysis of plant material and its occurrence in the fossil record can be broadly equated with the incidence of palaeowildfire. The past record of such naturally occurring fire, and tha availability of the biomass which represents its fuel, put two constraints on oxygen levels. For combustion of plant material to occur at all requires that the atmospheric oxygen did not drop below a threshold of 13%. Increasing inflammability of plant material at higher oxygen levels suggests that 35% would be a ceiling above which plant biomass would ignite and burn so readily as to be incompatible with sustained forest growth. As we have more or less continuous fossil evidence of forest trees from the Late Devonian onwards, and a similarly sustained record of fossil charcoal from that time to the present (Cope, 1984), this constraints oxygen levels between 13% and 35% over that period (Rabash and Langford, 1968; Watson et al., 1978). However, further experimental work is required to establish the validity of these oxygen values under appropriate conditions and also to sharpen the certainty by which we can discriminate between fusain produced by pyrolysis, and inert wood degradation products produced by other (? biogenic) means. We discuss experiments directed at attempting to establish the validity of physical parameters by which pyrolytically produced fusain can be characterized. The most convincing evidence of pyrolysis hitherto recognised is the apparent homogenization of xylem cell walls, as seen under SEM. Work on charcoal from both wildfires and laboratory wood charring under controlled conditions confirms the homogenization as seen under both SEM and TEM. Controlled temperature experiments show that a further rise in temperature causes the cell walls, initially homogenized, to crack and separate along the site of the middle lamella, giving the charcoal a characteristic fibrous texture. Both of these distinctive phases of response to pyrolysis can be observed in fossil charcoals.

The subduction history of the Neo-Tethys is critical for understanding the early-stage tectonic evolution of the Qinghai–Tibetan Plateau. Arc volcanics, which usually record the subduction process, thus can help trace the evolution of the Neo-Tethys. In this paper, we report for the first time zircon LA-ICP-MS U-Pb ages, whole-rock major and trace element geochemistry, as well as Sr–Nd–Hf isotopic data for the volcanic rocks from the Danshiting Formation at the southern edge of the Lhasa Terrane. Two samples collected from the Danshiting Formation volcanic rocks yield zircon U-Pb ages of 97.1 ± 0.8 Ma and 90.1 ± 0.7 Ma, respectively. The volcanic rocks of the Danshiting Formation are composed dominantly of basalts and andesites characterized by depletion of high-field-strength elements, low (87Sr/86Sr)i ratios (0.7042–0.7045), high eNd(t) (+2.1 to +2.7) and high eHf(t) values (mean + 11.6). These rocks show geochemical affinity of arc volcanic rocks. The volcanic rocks of the Danshiting Formation may have formed during the northward subduction of the Neo-Tethys. This paper, combined with the previous data, briefly divide the northward subduction of the Neo-Tethys into four periods: the Jurassic (195–150 Ma), when the magmatic activity was controlled by the northward high-angle subduction of the Neo-Tethys that produced volcanics of the Yeba and Bima formations; the Late Jurassic to Early Cretaceous (150–110 Ma), when the Neo-Tethys subducted at low-angles; the Late Cretaceous (110–80 Ma), when subduction was of the Andean-type and produced volcanic rocks of the Danshiting Formation; the Paleogene (70–40 Ma), when there was transition from ocean-to-continent subduction to continent–continent collision that produced volcanic rocks of the Linzizong Group.

In this paper, we conduct a palynological analysis of a high-resolution Holocene record from Cartagena Bay, southeast of the Iberian Peninsula, to establish paleoenvironmental variability of coastal areas in the western Mediterranean region at a centennial-scale over the last 7300 years. Statistical analysis of four palynozones allows reconstruction of paleotemperature and paleohumidity conditions. Pinus, steppic, xerophilous, and Mediterranean taxa persisted continuously through the record, and only during periods of increased humidity did deciduous and Mediterranean taxa expand (Zones II, subzone IIIb). Cooler and dry conditions favored the development of Cupressaceae and scrubs between 7300 and 7000 yr cal BP. The mid-Holocene (Northgrippian) mesophytic optimum took place between 6800 and 4000 yr cal BP during which time a Mediterranean climate was present and open forest developed, predominantly consisting of Mediterranean taxa and deciduous trees. The gradual rise in aridity in the Meghalayan (4000–1700 yr cal BP) led to Mediterranean forest being replaced by steppic and xerophilous vegetation, a change related mostly to a decrease in summer insolation, with superimposed centennial-scale variability in humidity. In parallel with forest degradation caused by increasing aridity, the record shows marked evidence of human influence since 4000 yr cal BP, which accelerated the progression of open landscapes from the Chalcolithic onwards, this change being especially marked during the Roman period. Significant denudation of the landscape can be attributed to the use of fire, as well as due to agriculture and grazing, with a major contributor being intense metallurgical and mining activity in the area. The Cartagena Bay record reported herein shows centennial-scale oscillations in humidity and temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The alternation of persistent North Atlantic Oscillation modes is likely to have played a key role in regulating humid–arid periods., This paper was made possible by Grant HAR2017-85726-C2-2-P (Cambios ambientales y ocupación humana en el sector central del sureste ibérico) funded by MCIN/AEI/10.13039/501100011033 and by Grant HAR2017-85726-C2-1-P (Carthago Nova desde su entorno litoral: Paleotopografía y evolución medioambiental del Sector central del Sureste Ibérico. Dinámica poblacional y productiva) funded by MCIN/AEI/10.13039/501100011033

Because the instrumental record is short and does not extend to periods before the initiation of significant human impacts, full understanding of the processes and dynamics involved in the modern phase of very rapid global change depends on the interpretation of high resolution and precisely dated proxy archives. The identification of very long-lived species of bivalve mollusc in the extratropical marine environment has been a crucial recent advance. These molluscs form patterns of periodic (usually annual) banding in their shells that are synchronous within populations, so that long (centennial and millennial) stacked chronologies can be built by crossdating from live collected to fossil shells. The variable growth rates and precisely dated geochemical data from the shell material provide long term real world data that can in principle be used to constrain climate models and to define long baselines for environmental monitoring. However, the signals in these data usually result from the complex interaction of multiple influences, and the deconvolution and understanding of these influences is a major target of the scientific field of sclerochronology. This special issue presents some of the latest research into the sclerochronology of mollusc shells. It includes contributions to our understanding of shell growth, including the identification of endogenous (non-environmental) growth rhythms that persist throughout ontogeny, and analysis in two papers of variability through ontogeny in the season of growth and the implications of such variability for temperature reconstruction. One paper presents a new network of bivalve chronologies for UK waters, with a 200-year seawater temperature reconstruction. Three papers cover trace element geochemistry, including a novel approach to sampling for LA-ICP-MS that enables giant clam shells to be sampled at daily resolution, an attempt to identify an independent temperature proxy for coastal waters using limpet shells, and a detailed study of the drivers of variability in Sr/Ca and Ba/Ca ratios. One study looks at shell microstructure as a temperature proxy, finding a coherent temperature response in the shape of the prisms.

This paper is a review article focussing on the research on past environments of Zimbabwe. The paper synthesises the current knowledge on palaeo-climates and other environmental parameters that inform debates and discussions on climate change and human adaptation. The study of palaeoenvironments provides environmental knowledge that chronologically goes beyond the range of written climatic records that are available in the country. The palaeoenvironmental data now available shows that our human ancestors in Zimbabwe have survived numerous climatic upheavals since the beginning of the Stone Age. However, limited research in the Stone Age and the variety of proxy data available creates a less coherent record. Extrapolation of evidence from the region makes the data less reliable for archaeological interpretations. The paper shows conflicting signals across the region at some specific periods. There are numerous gaps in the record. The paper concludes by calling for multidisciplinary research on the past environments of Zimbabwe.

In the comment on our paper, Cho and Cheong (2016) and Kim and Ree (2016) make a number of arguments that we did not discuss the Cambrian zircons from our data and have cast doubt on our early Cambrian paleogeographic reconstruction. They also argued that our data do not pass statistical tests between concerned strata for paleogeographic reconstruction. In response to the comment, we show that these arguments are not based on sound geological evidence and conditions that we provided in our paper.

With the discovery of the Bozhong 19–6 large gas field in the Bohai Bay Basin, the study of lacustrine source rocks in the southwestern Bozhong Sag has garnered new interest. In this paper, 107 source rock samples of the Paleogene Shahejie Formation (Es) from the southwestern Bozhong Sag were analyzed with organic and inorganic methods and compared with other sags in the Bohai Bay Basin to reveal the depositional environment and controlling factors of organic matter enrichment during the deposition of the Es. The formation of source rocks (average total organic content = 2.76%) was subject to a combination of high organic productivity and enhanced organic preservation. Also, this was reflected by the existence of nutrient elements of P and Ba as well as other high productivity-related elements such as Cu, Zn, and Ni. The moderate Mo enrichment factor, Pr/Ph and low to moderate (C/P)org ratios were an essential part of this organic preservation. Moreover, the evidence we observed for the existence of hydrothermal activities consisted of high contents of quartz and pyrite, large positive Eu anomalies, and enrichment of elements related to hydrothermal fluids. Hydrothermal influence may lead to similarities and fluctuations in water salinity, organic productivity and preservation in the third (Es3) and first (Es1) members of the Es. Hydrothermal fluids may play an essential role in promoting the development of high organic productivity, stable reducing environment, and brackish water (as shown by the range of B/Ga and TS/TOC) in the lakes during the source rock deposition. This paper may provide implications for gas accumulation mechanisms and a complete set of organic and inorganic experimental data for source rock analysis in other lacustrine rift basins.

The stable oxygen isotope composition of phosphates (δ 18 O P ) extracted from vertebrate bone and teeth material is widely used for paleotemperature reconstruction over the Quaternary period. However, inconsistency in analytical and statistical procedures used by different researchers for recalculation of mean air temperatures from measured δ 18 O P values makes integration of different data sets challenging. Therefore, consistency in both stable isotope data processing and the application of appropriate statistical procedures is highly desirable. This paper evaluates the uncertainty associated with two most commonly used regression methods, least-squares inverted fit and transposed fit. We assessed the performance of both fits by designing ‘real-life’ experiments using various data sets. We used both regression models to reversely calculate the differences between actual recorded in ‘real-life’ values and values calculated from the regression models. Our calculations clearly show that the mean absolute errors are always substantially higher for the inverted fit and the transposed fit always returned mean values closer to the values measured in ‘real life.’ In all studied scenarios, the predictive models performed better than causal models, returning mean absolute errors by 12–65% lower. In the paper, we also examined the other main sources of uncertainty, concerns about calculation of δ 18 O P of phosphates from δ 18 O C of carbonates, averaging of δ 18 O W in precipitation and highlight major challenges in the field of phosphate stable oxygen isotope biogeochemistry. The estimation of paleotemperatures from isotope records could be improved by employing globally consistent calculation procedures.

The paleoichnological site of Pehuen Co, located on the southern coast of Buenos Aires province, Argentina, was discovered in 1986 and the first paper was published in 1987. New discoveries made in the following years have revealed well-preserved Pleistocene mammal and bird footprints of high diversity. Investigations at this site have continued to the present. The most important aim of this paper is to revise the previous ichnotaxonomic assignations, and to present some new discoveries. The described tracks include eleven mammal (Neomegatherichnum pehuencoensis, Mylodontidichnum rosalensis, Glyptodontichnus pehuencoensis nov. igen. and isp., Eumacrauchenichnus patachonicus, Proboscipeda australis nov. comb., Dolichotichnus marae nov. igen. and isp., Ursichnus sudamericanus nov. isp., Hippipeda isp., Lamaichnum guanicoe, Lamaichnum tulipensis nov.comb, Pecoripeda commune nov. comb.) and four bird icnotaxa (Phoenicopterichnum pehuencoensis, Charadriipeda isp., Gruipeda isp., and Aramayoichnus rheae nov. igen. and isp.). The second goal of this paper is to emphasize the worldwide significance of the Pehuen Co site relative to other Pleistocene vertebrate tracksites. Pehuen Co site is unique because of the quality of preservation, and the abundance and diversity of the footprints.

L'Arbreda Cave is one of the southernmost of the Reclau Caves (Serinya, Girona, northeastern Iberian Peninsula), located between the west margin of the Pla d'Usall and the Serinyadell river, at an altitude of about 211 m a.s.l. The Pla d'Usall forms part of the Banyoles-Besald Basin, which is bounded by Eocene and Neogene reliefs. It is filled with sediments of Plio-Pleistocene age. The cave is a shelter formed by travertine cascades with a degree of karstification, and contains sedimentary deposits ranging from the end of the Middle Pleistocene to the Early Holocene, thus constituting an important archaeo-palaeontological record for an understanding of the prehistoric occupation of northeastern Iberia. It is one of the most complete and best-dated terrestrial sequences in Iberia from the Mousterian to the Early Holocene period. In this paper we present a palaeoenvironmental and palaeoclimatic reconstruction of the sequence based on non-flying small mammals (insectivores and rodents) and pollen analyses. The environmental and climatic results, together with the absolute dating of the sequence and direct comparison with NorthGRIP delta O-18 and the sea-surface temperatures (SST) of the Alboran Sea, allow us to identify various climatic periods within our sequence: a cold period between interstadials 12 and 10 in Level I, probably interstadial 10 in Level H-2 the Last Glacial Maximum (LGM) in Levels C and B, the Bolling-Allered interstadial (B/A) in Level A, and the Preboreal/Boreal (Pr/B) in the Terra Rossa Level We want to thank the editor Dr. Paul Hesse and the three reviewers (Prof. Gloria Cuenca-Bescos and two anonymous) for their comments that improve the final version of the manuscript. This paper is part of the projects HAR2013-48784-C3-2-P, CGL2012-38358 and 2014-SGR900. Excavations ara funded by "Conselleria de Cultura Generalitat de Catalunya". J.M. Lopez-Garcia is a beneficiary of a Beatriu de Pinos postdoctoral fellowship (2011BP-A200001) from the Generalitat de Catalunya, a grant co-funded by the European Union through the Marie Curie Actions of the 7th Framework Program for R + D

As an important tool in natural resource exploration, palaeogeography provides a portrayal of deep time Earth. The South China Block located in the eastern Palaeotethys includes multiple natural resources (e.g., coal, shale gas, bauxite, etc.) in the Permian, which are well known for their important economic significance. In this paper, data gathered from literature amount to 431 stratigraphic sections of Wuchiapingian age from South China. These data were quantitatively analyzed and dynamically reconstructed in the global context under the revised plate motion model by GPlates software for the first time. A schematic 3-D model was constructed based on the high-resolution reconstructions in this paper, showing two relatively large highlands developed in the South China Block during the Wuchiapingian, including the Kangdian Highland in the west and the Cathaysia Highland in the east and a small Yunkai Highland in the south. A broad platform-dominated depositional system with small uplifts and depressions was developed between these two highlands. These reconstructions show great potential to explore enriched coal seams and shale gas in the peripheral areas of the two ancient highlands in the west and east of the South China Block. Based on the dynamic evolution of this depositional system, South China experienced an overall sea-level rise with frequent secondary transgressions and regressions during the Wuchiapingian. This is in contrast to the widespread continental and evaporite deposits on much of Pangea and its surrounding margins after the end-Guadalupian global regression. Compilation of conodont biostratigraphic data suggest that the temporal and spatial constraints on the unconformity across the Guadalupian-Lopingian boundary (GLB) resulted from Dongwu Uplift movement. The regression began during the Jinogondolella shannoni Zone and ended in the Clarkina leveni Zone, but the response time varies in different localities of South China. These results provide detailed information about sea-level eustacy, tectonic uplift, sedimentary hiatus, resource accumulation and palaeoclimate change from the South China Block during the Wuchiapingian.

The Permian formations of the South African Karoo Basin play a crucial role in understanding Gondwana's climate history during this time of major global changes. In this paper we present two data sets, one from the coal-bearing Vryheid Formation (Witbank Basin) and one from the Whitehill and Upper Prince Albert formations of the DP 1/78 core (NE Karoo). Our main goal was to study the vegetation changes during this period of global warming and test if the climatic signals could be used to correlate the basinal Ecca group facies with the fluvio-deltaic coal-bearing strata of the Witbank Basin. The palynological record of the No. 2 Coal Seam of the Vryheid Formation indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. The data set of the DP 1/78 core is interpreted to represent a cool to warm temperate climate represented by a high amount of Gangamopteris and Glossopteris elements. Both data sets are very different in their composition, which can be explained by the differences in depositional environment; however, our findings reveal a different age of the studied assemblages and thus also suggest that both data sets represent different stages in the transition from icehouse to greenhouse during Permian times. As the stratigraphic correlation between the Main Karroo Basin and the peripheral basins is still under discussion, this paper provides new data to underpin the stratigraphic placement of the Whitehill Formation relative to the coal-bearing Vryheid Formation.

In the comment on our paper, Forel and Crasquin (2015) make a number of very strong criticisms that attempt to cast doubt on everything in our study. We thank them for their detailed discussion of our paper, especially the taxonomic and methodological issues and the insightful explanations on the causes of the reduction of ostracod size. However, many of their criticisms are excessive. Our paper focused on the change of ostracod size across the Permian–Triassic boundary according to reliable data, and several probable causes were presented. We accept some of the comments by Forel and Crasquin (2015), but these do not negate the core conclusions of our original paper.

In their comment, Oviatt et al. (this issue) criticize and dismiss our recent paper (Nishizawa et al., 2013) by arguing that it contains misinterpretations and unreliable radiocarbon ages, and therefore that our findings will confuse many people trying to understand the lacustrine chronology of the Bonneville basin. Their comment, however, does not present evidence to substantiate their criticisms against our paper. Oviatt et al. attribute statements to the paper that are not found in it, and their attempt to re-graph the radiocarbon ages omits 13% of our data. Numeric ages that Oviatt et al. contend are conflicting either are not or are not as problematic as those commenters claim. Comparisons of our lake-interval interpretations with sediment-core data likewise do not show the contradictions that Oviatt et al. claim. In essence, Oviatt et al. seem to advocate complete dismissal of all of our numeric ages and lake-size interpretations regarding MIS 3 on the basis of one tufa age. The following sections identify the incorrect information presented in the comment by Oviatt et al., review the complete set of numeric ages for the contested intervals, and respond to the implication that our late colleague, mentor, and coauthor, Donald R. Currey, did not actively participate in this research.

Martínez and Rojas (2013) published a paper about the relative sea level during the Holocene in Uruguay. The paper of Martínez and Rojas could be handled as an attempt to construct a sea-level curve from data collected from different sources: open-ocean coast, the Río de la Plata coastline and the outlet of Uruguay River. In this sense, several processes were involved: storm effects at open-ocean beaches, the Holocene enclosing of coastal lagoons, storms within the funnel-shaped estuary and the floods of the Uruguay River. However, they included a series of omissions, inaccuracies, errors and critics to our work, that need to be amended, rectified and argued. In response we present a historical background about the research on this issue in Uruguay. We refute the comments about the empirical framework used to construct the first sea-level curve for Uruguay (Bracco et al., 2008, 2011b). We point out that the assumptions on which the curve proposed by Martínez and Rojas (2013) is based are mistaken. In addition, there are limitations of the performed statistical techniques, and errors — mainly systematic — within their formulation. We present evidence that the decrease in sea level from middle Holocene would not have been constant. Instead, a rapid sea level decrease would have taken place by 4300 yr BP. Finally, we not only compare our sea level curve with that proposed by Martínez and Rojas, but also we corrected the altimetry errors incurred in their formulation. We conclude that the similarity supports the validity of our curve. Fil: Bracco, Roberto. Universidad de la República; Uruguay Fil: Inda, Hugo. Universidad de la República; Uruguay Fil: del Puerto, Laura. Universidad de la República; Uruguay Fil: Capdepont, Irina. Universidad de la República; Uruguay Fil: Panario, Daniel. Universidad de la República; Uruguay Fil: Castiñeira Latorre, Carola. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Mineralogía y Petrología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Garcia Rodriguez, Felipe. Universidad de la República; Uruguay

Although clypeasteroid echinoids are very common in the shallow water sediments of the Miocene of Sardinia, they have received little attention as far as their origin is concerned. In this paper, three sand dollar dominated mass accumulations from the Lower Miocene of Sardinia are studied and compared in order to understand their genesis and palaeoecology. Two clypeasteroid assemblages were found in the Sarcidano region (Central Sardinia) within the Nurallao Formation (Late Oligocene–Burdigalian). The third sand dollar mass occurrence crops out in the Logudoro region (northern Sardinia) within the Calcari di Mores Formation (Late Burdigalian). These fossil echinoid deposits show a low taxonomic diversity; two assemblages are dominated by the genus Amphiope while the other is dominated by Parascutella with subordinate Clypeaster. An integrated stratigraphic, taphonomic and sedimentological approach allows different genetic mechanisms for these shallow water, sandy, shoreface deposits to be inferred. The origin of these deposits is related to ecological, morphological and sedimentological factors. The sand dollars of Cuccuru Tuvullao (Nuragus) show high degrees of abrasion and fragmentation and represent a multiple in situ reworked accumulation while the assemblage of Duidduru (Genoni), with low abrasion and variously oriented complete and fragmented specimens constitutes an example of a proximal storm deposits. The sand dollar bed of Monte Sa Loca (Chiaramonti) consists of a dense accumulation of well-preserved, mainly concordant-oriented, juvenile and adult specimens and is considered to represent an autochthonous assemblage. This paper explores the role of detailed sedimentological and taphonomic analysis in the palaeoecological and genetic interpretations of the sand dollar beds and points out the widespread distribution and diversification of these echinoids in the Miocene deposits of the Mediterranean area.

Fluvial systems in tropical regions are not only the lifeline for modern civilizations there but also form an important continental archive for reconstructing Quaternary palaeoclimates and palaeoenvironments. Tropical rivers drain through a variety of geological and geomorphological settings across the world and have been studied for their hydrology, sediment transport characteristics, facies models, stratigraphic development and flood hazards. This paper presents an overview of the research on tropical rivers globally and identifies major gaps and unanswered research questions. As a part of the IGCP 582 on Tropical Rivers, the participants of this project are continuing to tackle many of these issues. The collection of papers in this special issue is an outcome of this activity and presents new data on processes and alluvial stratigraphy of the tropical rivers from China, India, South America and northern Australia.

This paper deals with the so-called Middle Pleistocene revolution, that is, the transition between the Early and Middle Pleistocene between 1.2 and 0.5 million years ago. Our knowledge about biotic changes during this transition has been so far largely based on studies of large mammals. Here we address the issue whether all faunal groups were equally affected. Three datasets have been used: (a) European large mammals present in the Middle and Late Pleistocene, (b) European fossil bird species recorded from the Early, Middle and Late Pleistocene of Europe, and (c) present-day birds currently classified in subfamilies that contain at least one Palaearctic representative species. Each species was allocated to all those geographical areas, climates, habitats in which it is present today; migratory status was also recorded. These datasets serve to undertake a biochronological analysis of mammal and bird groups, thus establishing patterns and processes of extinction and survival at the genus and species levels. The end of the Middle Pleistocene appears to have been a significant boundary in respect of herbivorous mammals, which suffered considerable depletion. In contrast, most genera and species of European birds in the Middle Pleistocene survived into the Late Pleistocene, even to the present day. Furthermore, at least 58% of the Middle–Pleistocene bird species were already present in the Early Pleistocene record. The most successful survivors in the Palaearctic Pleistocene were species from genera that had been the most climatically-tolerant during the late Cenozoic, usually from speciose and widely-distributed genera. We conclude that major transitions in Earth history have leant largely on biochronology and the perceived turnovers of faunas. Boundaries have usually depended heavily on changes to specific taxa of organisms. In this paper we show that what may appear as epic boundaries are largely scale- and taxon-dependent. Their usefulness must therefore be open to question. Here we advocate an individualistic and taxon specific approach in understanding the major ecological changes that have marked the history organisms.

In their recent paper, Hong et al. (2010 ; Anti-phase oscillation of Asian monsoons during the Younger Dryas period: Evidence from peat cellulose δ 13 C of Hani, Northeast China, Palaeogeography, Palaeoclimatology, Palaeoecology 297, 214–222) discuss bulk peat sample cellulose δ 13 C data from a fen in northeast China as a proxy for East Asian summer monsoon intensity during the Late Glacial period. Based on their own results, cited papers, and an extensive re-interpretation of sedimentological and palynological data from nearby Lake Sihailongwan, Hong et al. (2010) construct a hypothesis of contrasting moisture conditions in northern and southern China, with wet conditions in the north during the Younger Dryas period and an anti-phase behaviour of Indian- and East Asian summer monsoon intensity. However, we do not approve of the re-interpretation of our Lake Sihailongwan data by Hong et al. (2010) and must strongly reject it. We show here that neither the Hong et al. (2010) fen data, nor the Lake Sihailongwan data or any other cited data allow for the sound assumption of an intensified East Asian summer monsoon in northeastern China during the Younger Dryas. The Late Glacial variability of the fen data found by Hong et al. (2010) can be easily explained by changes in the plant assemblage down core and thus by the composition of the peat. Furthermore, the use of bulk peat cellulose δ 13 C data as a precipitation proxy remains unproven for that area. Hence, there is no basis for a model contrasting Indian and East Asian summer monsoons during that period.

The Late Palaeozoic Ice Age (LPIA), spanning approximately from ~320 Ma (Serpukhovian, late Mississippian) to 290 Ma (mid-Sakmarian, Early Permian), represents the vegetated Earth’s largest and most long-lasting regime of severe and multiple glaciations, involving processes and patterns probably comparable to those of the Last Ice Age. Accompanying the LPIA occurred a number of broadly synchronous global environmental and biotic changes. These global changes, as briefly reviewed and summarized in this introductory paper, comprised (but are not limited to) the following: massive continental reorganization in the lead up to the final assembly of Pangea resulting in profound changes in global palaeogeography, palaeoceanography and palaeobiogeogarphy; substantially lowered global atmospheric carbon dioxide concentrations ( p CO 2 ), coupled with an unprecedented increase in atmospheric oxygen concentrations reaching Earth's all-time high in its last 600 million year history; sharp global temperature and sea-level drops (albeit with considerable spatial and temporal variability throughout the ice age); and apparently a prolonged period of global sluggish macro-evolution with both low extinction and origination rates compared to other times. In the aftermath of the LPIA, the world's climate entered into a transitional climate phase through the late Early to Middle Permian before its transformation into a greenhouse state towards the end-Permian. In recent years, considerable amount of data and interpretations have been published concerning the physical evidence in support of the LPIA, its broad timeframe and eustatic and ecosystem responses from the lower latitudes, but relatively less attention has been drawn to the impact of the ice age on late Palaeozoic high-latitude environments and biotas. It is with this mission in mind that we have organized this special issue, with the central focus on late Palaeozoic high latitude regions of both hemispheres, that is, Gondwana and northern Eurasia. Our aim is to gather a set of papers that not only document the physical environmental changes that had occurred in the polar regions of Gondwana and northern Eurasia during the LPIA, but also review on the biotic responses at different taxonomic, ecological and spatial scales to these physical changes in a refined chronological timeframe. This introductory paper is designed to provide a global context for the special issue, with a brief review of key late Palaeozoic global environmental changes (including: changes in global land-sea configurations, atmospheric chemistry, global climate regimes, global ocean circulation patterns and sea levels) and large-scale biotic (biogeographic and evolutionary) responses, followed by a summary of what we see as unresolved scientific issues and various working hypotheses concerning late Palaeozoic global changes and, in particular, the LPIA, as a possible reference to future research.

Charcoal, predominantly the product of wildfires, is abundant in many sedimentary rocks deposited in a wide range of environments, from terrestrial to marine. It also occurs in some volcanic rocks. This paper outlines aspects of charcoal formation (both natural and experimental) and briefly considers the taphonomic processes leading to a final assemblage. This is done using examples from recent fires and through experimentation. The ways in which charcoal assemblages are recognized in the field and extraction in the laboratory are also considered. Methods of charcoal identification are presented. The range of charcoalified plant organs that can be found is discussed and a wide range of study methods outlined (including light microscopy, dark field light microscopy, reflectance microscopy, scanning electron microscopy and synchrotron radiation X-ray tomographic microscopy). Emphasis in this paper is on the study of macro- and meso-charcoal (above180 µm). Finally there is a consideration of the broad use of charcoal from plant evolution studies, fire history studies, vegetation studies, anatomical studies, climate and atmospheric studies and the wider importance of charcoal for the Earth and Biological Sciences. Charcoal is information rich but yet is an under-utilized resource.

Reconstructing the phylogeny and biogeography of the Caribbean land snail Cerion requires a robust stratigraphic and chronological framework. To this end, we have determined the stratigraphic succession on San Salvador, a Bahamian island with a rich fossil and modern Cerion fauna. A primary purpose of this paper is to independently verify this succession through whole-rock and Cerion aminostratigraphies and AMS 14C-based age models. Over 150 individual Cerion shells were age-ranked from 140 ka to modern using stratigraphic position and reverse-phase HPLC (RPC) amino acid racemization, which was sufficiently sensitive to resolve stratigraphic subunits within the Holocene and late Pleistocene. A secondary purpose of this paper is to assess broad changes in the gross morphology (height, width) of supersets of Cerion from age-ranked lots spanning this ~ 140 kyr chronostratigraphy. Through each of the three interglacial sequences (i.e., marine isotope stages 5e, 5a, and 1), between-sample trends in mean gross morphology often greatly exceed within-sample variances (± 1σ). Live-collected Cerion exhibit a range in gross morphology that nearly encompasses that of the entire fossil sequence. A trend of increasing gross shell size characterizes each of the interglacial phases, with a major step-decrease between marine isotope stages 5a and 1. While between-unit variation is often great in Cerion from SSI, within-unit variation appears unimodal through the record.

Palaeoenvironmental reconstructions of lake sediment records have been greatly facilitated by statistical comparisons with microfossil assemblages from the surface sediments of modern lakes. These modern sub-fossil assemblages from different lakes, which are often referred to as “training-sets”, attempt to incorporate gradients of environmental parameters, such as e.g., temperature and phosphorus, are of interest for paleoenvironmental reconstruction. One major assumption of quantitative palaeoenvironmental reconstructions requires that the environmental variable to be reconstructed is, or is linearly related to, an ecologically important determinant in the ecological system of interest, and that the joint distribution with other variables in the fossil set is the same as in the training-set. The motivation for this paper is that present-day diatom species abundances in surface-sediment samples are often influenced by several environmental gradients. Partial least squares (PLS) or weighted-averaging partial least squares (WA-PLS) regression methods can be used to adjust species optima, if the additional PLS components, which are orthogonal to previous PLS components, are included. This paper tests a reproducible approach for reducing the influence of background variables within a diatom training-set to produce a “screened” training-set, which focuses on the variable of interest. In our example total phosphorus (TP) is the variable of interest. The initial training-set consists of modern Swiss lakes along an elevation gradient spanning 2005 m (334 to 2339 m a.s.l.), which follows a TP gradient from 522 to 3 μg L− 1. However, high-elevation lakes are not distributed equally along the TP gradient. They are meso-oligotrophic because high-elevation eutrophic lakes are rare in Switzerland. This leads to a potential confounding effect between the elevation and the nutrient gradients. These higher elevation lakes were selectively excluded, using Monte Carlo permutation tests, until the conditional effect with respect of covariables of elevation was no longer significantly related to the relative abundance of diatoms. The initial and screened inference models for log TP were applied to fossil assemblages from varved sediments at Greifensee (Switzerland), which cover the past century. The evaluation of the reconstructions with measured TP (1954–1994) demonstrates that the smaller (screened) subset performs better than the larger, more heterogeneous, initial data-set when the same number of components are included. The slope of the relation between measured and inferred log TP changed significantly for the reconstructions using partial least squares, with one and two components, and for reconstruction using weighted averaging partial least squares with two components. According to our interpretation, the accuracy of the reconstructions improved because modern diatom abundances of the smaller subset are controlled mainly by log TP and lakes are more equally distributed along the log TP gradient. This approach of reducing the influence of background variables is applicable to other heterogeneous training-sets, such as merged training-sets, in order to homogenise the background variables and to maintain the gradient of interest.

The relative importance of tectonism and sea-level change in driving Middle to Late Devonian biogeographic patterns in marine invertebrates is investigated using phylogenetic biogeography. Taxa considered include two clades of brachiopods, one bivalve clade, and a suborder of phyllocarid crustaceans. These organisms colonized different depositional environments and played different roles in the Devonian ecosystem which allows biogeographic patterns to be considered in a cross-faunal analysis. Vicariance patterns are well resolved and may reflect biogeographic relationships developed in the Early to early Middle Devonian due to the uplift of intracratonic arches. Uplift of tectonic arches is inferred to occur during times of tectonic quiescence during the second and third (and possibly also the first) tectophase (after Ettensohn, F.R., 1985. The Catskill Delta complex and the Acadian Orogeny: a model. In: Woodrow, D. L., Sevon, W. D. (Eds.), The Catskill Delta. Geological Society of America, Boulder, CO, Special Paper 201, pp. 39–49. ) of the Acadian orogeny. Geo-dispersal patterns are not as well resolved, but may indicate dispersal across tectonic arches during downwarping associated with increased compressional tectonism during Ettensohn's (1985) [Ettensohn, F.R., 1985. The Catskill Delta complex and the Acadian Orogeny: a model. In: Woodrow, D. L., Sevon, W. D. (Eds.), The Catskill Delta. Geological Society of America, Boulder, CO, Special Paper 201, pp. 39–49] tectophases II and III. Geo-dispersal across relatively low arches may also be coincident with transgressive events IIa and IIc of Johnson et al. (1985) [Johnson, J.G., Klapper, G., Sandberg, C.A., 1985. Devonian eustatic fluctuations in Euramerica. Geological Society of America Bulletin 96, 567–587]. The overall lack of congruence between the vicariance and geo-dispersal patterns suggests that singular, tectonic events exerted more profound influence on Devonian biogeography than cyclical changes in sea level. Furthermore, the offset in perceived timing between vicariance and geo-dispersal patterns may indicate a fundamental change in the style of biogeographic patterns during the Middle Devonian and may have played a major factor in regulating biodiversity dynamics during the Late Devonian biodiversity crisis.

More than 10 years after the 1991 Gulf War oil spill on the Saudi-Arabian coast of the Arabian Gulf, natural remediation has only been partially successful. This fact demonstrates the importance of studying the preconditions for, and the process of, hydrocarbon degradation as well as the competing processes which prevent or slow them down. This paper deals with the preconditions of biodegradation: the presence of water, the availability of oxygen, the influence of temperature and the presence and type of degrading microorganisms. This paper discusses abiotic transformation as well as aerobic and anaerobic biodegradation. The importance of emulsification and hydrocarbon uptake into the degrading microorganisms is underlined. Competing processes include the conversion of liquid oil to viscous and finally solid material, the formation of solid sediment–oil mixtures and the clogging of sediment pores preventing oxygen from entering the pores. At first glance, the competing processes seem more “geological” while emulsification and hydrocarbon uptake seem more “biological”. However, since the necessary energy input (e.g., waves and turbulence) is “geo”(physical), it becomes clear, on the one hand, that the biological process requires geophysical energy input and, on the other hand, is inhibited by geological competition. Oil pollution as well as remediation progress affect the impacted environment since they leave undegradable residues and intermediates as well as microbial biomass and its conversion products. Sediments are enriched with organic matter, whose properties and behaviour are altered. Even inorganic matter may be formed during hydrocarbon biodegradation. The final part of this paper consists of case studies of the accident of the tanker BRAER (1993), the oil spill in the Arabian Gulf (1991), and the continual seeping of the wreck PRESTIGE (2002/03). These three cases demonstrate the importance of oil type, energy input, climatic conditions, as well as human interest in the use of the impacted coast, in determining speed and success of remediation and possible restoration measures.

Ostracods are microcrustaceans that grow by moulting (eight to nine instars in most cases) and, consequently, studies of its populations need the application of some special techniques. The population age structure techniques [Whatley, in: Ostracoda in the Earth Sciences, 1988, pp. 245–256] are a simple statistical method to estimate paleoenvironmental conditions in fossil/Recent populations of ostracods. For its application, it is necessary to determine the percentages of each instar present in the samples studied, in order to analyze the different types of population age structure histograms and their (paleo-)environmental interpretations. Some potential applications are the (paleo-)energy levels or the sedimentation rates. In this paper, these special techniques are applied to Recent populations of the ostracod Pontocythere elongata collected in littoral sediments of southwestern Spain. In this area, the relative percentages of this species and the adult percentages are closely related with depth and consequently this species was used as a bathymetrical tracer in shallow Neogene areas of the Guadalquivir Basin. In addition, a first three-step multivariate analysis permits the definition of three groups, closely related to the theoretical models proposed by Whatley: (a) Group 1 structure or biocoenosis, present either in Recent low- to medium-energy environments located in erosional coastal stretches and Neogene fair-weather conditions; (b) Group 2 structure or high-energy thanatocoenosis, observed either in Recent river mouths with groynes and Neogene storm and post-storm conditions; and (c) Group 3 structure or low-energy thanatocoenosis, characteristic of Recent, progradational coastal areas and present in the Recent–Neogene deeper areas analyzed in this paper (30–40 m depth). This separation is mainly controlled by intrinsic factors (i.e. the natural growth of this species), whereas the extrinsic factors (i.e. the hydrodynamic levels) are only a minor cause of the distribution of this species in the area studied.

The Middle Triassic vertebrates are proving to be very important witnesses not only to the post P/Tr crisis recovery, but also of the palaeobiology and paleogeography. The western Tethys (especially the Monte San Giorgio fossiliferous series) and the Germanic Basin are of particular interest as they show similar vertebrate assemblages in somewhat different environmental patterns and ages. Furthermore, the MSG specimens are usually complete and concentrated in different levels spanning from Late Anisian to Late Ladinian, while vertebrates of the Germanic basin often consist of scattered remains, sometimes gathered in bone-beds. In the last years Diedrich proposed a number of restorations, concerning both organisms and palaeoenvironment. Very often his work does not consider other authors' papers, and a few concepts, such as the supposed ‘anatomic convergence’ between a sauropterigyan reptile and a mammal, appear scientifically unsound. In this comment the author points out some uncertain data and unproven conclusions in Diedrich's paper.

Consensus among the Friends of Paleobiogeography produced tentative guidelines to the classification and nomenclature of marine biogeographic units, i.e. biochores. Based on these loose ‘rules’, the present paper is a critical review of all published Mesozoic marine Realms, Subrealms, and ?Superrealms (formerly called ‘climatic belts’).Biochores are defined by the overall endemism within geographic and time envelopes that include choro- and chrono-types, without consideration of facies or climate. The hierarchy of ranks or tiers is: ?Superrealm, Realm, Subrealm, Province, Subprovince (only ranks in italics are obligatory); ‘region’ is informal. These ranks scale with endemism, geographic range, and persistence in time. Biochores are named geographically, following nomenclatural guidelines (not strict rules) of synonymy and homonymy, with priority beginning with Uhlig's paper of 1911. Uhlig's two ‘climatic belts’ are tentatively accepted as optional, top-ranking ‘Superrealms’ for times of exceptional global endemism; available names for them are ‘Euroboreal’ (or ‘Panboreal’, new) and ‘Tethys–Panthalassa’. The validity of the 29 existing names for realm-group biochores (Realms, Subrealms and Superrealms) in the marine Mesozoic is discussed; 19 names are rejected for a variety of reasons, including synonymy, homonymy and usefulness. The most important realm-group biochores are: Arctic and Boreal–Atlantic in the Boreal/?Euroboreal Realm or ?Superrealm; and Tethyan, Mediterran–Caucasian, Indo-Pacific (Jurassic–Early Cretaceous) and Austral (Middle–Late Cretaceous) in the ?Tethys–Panthalassa ?Superrealm.

Qualitative and quantitative changes in fossil flora and fauna have been used in many studies to infer climatic change. Here we ask a different question: how do flora and fauna respond to climatic changes such as rapid warming or cooling? As an independent proxy for paleotemperature we take the ratio of oxygen isotopes in biogenically precipitated lake marl and in ostracod shells. This introductory paper describes the project design and the five sites on an altitudinal transect from 600 m to about 2300 m asl in the western Swiss Alps. As cases of climatic cooling and warming we use the beginning and end of the Younger Dryas as major changes, and the Gerzensee and Preboreal oscillations as minor changes. At the two sites of Gerzensee and Leysin these changes are recorded in stable-isotope ratios, and there the time scales can be derived by correlations to the GRIP ice core ( Schwander et al., 2000 , von Grafenstein et al., 2000 ). Biotic responses to climate changes are treated in individual papers using pollen ( Wick, 2000 ), plant macrofossils ( Tobolski and Ammann, 2000 ), and remains of chironomids ( Brooks, 2000 ), beetles and other insects ( Lemdahl, 2000 ), and chydorid Cladocera ( Hofmann, 2000 ). They are followed by a synthesis focusing on quantification of biotic responses ( Ammann et al., 2000 ). In addition, a reconstruction of summer temperatures for the Allerod and the Younger Dryas at Gerzensee is provided by Lotter et al. (2000) .

In a recent paper (Heydari, E., Arzani, N., Hassanzadeh, J., 2008. Mantle plume: the invisible serial killer — application to the Permian–Triassic boundary mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology 264, 147–162) the cause of the end-Permian mass extinction was once again associated with the eruption of the Siberian Traps. However, this work considered the vast outpouring of flood basalts to be an incidental sideshow to the main event: the catastrophic release of huge volumes of methane to the atmosphere. This was attributed to a selection of sources – marine gas hydrates, thermogenic methane and methane from permafrost – that have been proposed by many authors previously. Uniquely, they suggest that the mantle plume (envisaged to have sourced the flood basalts) impinged beneath oceanic crust to the north of the Siberian flood basalts and that feeder dykes in the continental slope to the south heated sediments and released methane. There is no evidence for either of these two new proposed facets to end–Permian volcanism. The paper invokes an "oceanic acid bath" kill mechanism and dismisses claims for ocean anoxia at this time instead suggesting that end–Permian oceans were as well ventilated as those pertaining today. This latter claim simply ignores a vast body of sedimentological, palaeoecological and geochemical evidence for widespread anoxia in ocean and shelf settings at this time. The former claim for ocean acidity is equally suspect and based on the notion that a transition from calcite to aragonite-precipitating seas occurred at the Permian–Triassic boundary. However, previous studies have suggested that this interval occurs within a phase of "aragonite seas" and it is significant that most of the principal contributors to carbonate sediment in the Late Permian (calcareous algae and foraminifera) secreted aragonite.

This paper presents first a discussion on the status of the subdivisions of the European Neogene mammal chronology and second, it synthesizes all available magnetostratigraphic data from Europe to provide chronological framework for mammal localities, mammalian events and mammalian biochronologic units of the European Neogene. Because of the lack of their rock equivalents, the subdivisions of the European Neogene, based on mammals, have not attained the stage status in terms of reliability, except the Vallesian and Turolian. Therefore they are designated as the European Land Mammal Ages (ELMA). Magnetostratigraphic data on mammal-bearing deposits in Europe is still scarce in time and space; consequently, it is not yet possible to correlate accurately all ELMA and MN zones with the geomagnetic polarity time-scale (GPTS). Nevertheless, several studies dealing with mammal localities (and their deposits) around the Oligocene/Miocene boundary, in the middle and late Miocene provide reliable correlations of some ELMA and MN zone boundaries. Thus, the calibration of the Oligocene/Miocene boundary at the base of Chron C6Cn.2n is in agreement with its age in marine deposits. The well-known Hipparion Datum (Astaracian/Vallesian boundary) is now dated as about 10.8 Ma, occurring slightly above the base of Chron C5n.2n. This paper also reviews magnetostratigraphic correlations of some late Miocene and Pliocene mammal localities in the Paratethys area. Taking into account the chronological assessments in other parts of Europe for some key mammalian events, new correlations with the GPTS have been proposed for these localities. Thus some new ages are suggested for the late Miocene and Pliocene Paratethys stages.

This paper continues the investigation of regional palaeoclimates in Australia at 18,000 yr B.P. using the method set out in Hubbard (1995). Initial research showed that while the palaeodata were, on the whole, in keeping with climates retrodicted for the northern part of the continent, there was substantial disagreement between the data and retrodictions in the south of Australia. While several possible reasons for this disagreement are considered in this paper, it is the author's conclusion that the 18,000 yr B.P. run of the Community Climate Model placed the southern boundary of the mid-latitude belt of high pressure south of its actual position. New seasonal circulations based on a northward position of this belt are outlined in this paper and, using the method given in Hubbard (ibid.), new climate retrodictions are given for each of 12 Australian regions. These new retrodictions are almost entirely in keeping with the published data review, suggesting that the Community Climate Model (0 run) pressure results were incorrect. The revised seasonal circulation patterns can be used, therefore, to reconstruct likely palaeoclimates of regions that currently have few or no palaeoclimatic data.

The early Paleogene continental sequence of northwestern Wyoming and south central Montana (USA) and the Neogene Siwalik sequence of northern Pakistan are exceptionally long, fossiliferous, and well studied in terms of geology, paleontology, mammalian evolution, paleoecology, and paleoclimatology. Each record spans about 15 myr of alluvial deposition in a foreland basin. The fluvial systems differed in size, drainage of floodplains, and change in alluvial architecture through time. Both sequences preserved abundant paleosols, which are a source of paleoclimatic signals in stable isotopes from soil carbonates. Fossil collections from both records are dominated by vertebrate remains and especially by mammals; the Paleogene sequence also preserved abundant floral remains. Patterns of vertebrate preservation differed markedly between the two sequences, placing inherent limitations on paleoecological reconstruction and on the scope of evolutionary studies of mammalian lincages. In this introductory paper, we summarize the major similarities and differences in geologic setting, chronology and time resolution, and mammalian faunal composition of these two long sequences. Finally, we present a brief overview of the organization of papers in this special issue.

Contributions to this special issue have compared the tectonic settings, fluvial systems, paleoclimates, paleofloras and faunas, vertebrate taphonomy, and mammalian paleoecology and evolution from two long, continental records of Cenozoic ecosystems. In this concluding paper, we summarize highlights of earlier papers to provide an overview of similarities and differences between these Paleogene and Neogene records. The relative influences of tectonic, climatic, and fluvial processes on lithofacies, environments of fossil preservation, and the productivity of the fossil record are compared for each sequence. Tectonism was the primary control on sediment accumulation rate and the distribution of major depositional environments in each basin. Fossil productivity, species richness, and the distribution of fossil localities among fluvial environments change across formation boundaries in each sequence. The taxonomic, temporal, and spatial resolution of vertebrate assemblages varies among fluvial environments and differs between the two sequences. As a result, the Paleogene record is better suited for detailed study of evolutionary change within local lineages and the Neogene record for detailed paleocommunity reconstruction. Several aspects of biotic change are considered. (1) The timing and magnitude of mammalian faunal turnover in relation to climatic change are evaluated in terms of three models of evolutionary change within ecosystems: Van Valen's “Red Queen model,” Stenseth and Maynard Smith's “stationary model,” and Vrba's “turnover-pulse model.” In both records, climatic change was accompanied by change in faunal composition and ecological structure, but both pulsed and diachronous biotic change, at a resolution of about 0.5 m.y., also occurred over periods when no significant climatic change was discernible. This pattern best matches the predictions of the Red Queen model. (2) In both records, the rate of mammalian faunal turnover (first and last appearances of taxa) is not highly correlated with standing richness, suggesting that paleocommunities were not a equilibrium richness on these time scales. (3) In the Paleogene record, plant species richness declined while mammalian species richness increased. (4) In each sequence, some episodes of mammalian faunal turnover were in step with changes in size or trophic structure, while other changes in faunal composition entailed no corresponding change in ecological structure. While both records would benefit from improved paleoclimatic, temporal, species-level, and ecomorphological resolution, this initial synthesis suggests that both physical and biotic factors were important influences on faunal composition, the timing and rate of turnover, and ecological structure in these paleocommunities.

Rousseau, D-D, 1990 Methods for the study of stratlgraphlcal records -- Introduction to Methods and Concepts m European Quaternary Stratigraphy " Palaeogeogr, Palaeochmatol, Palaeoecol, 80 I-6 The International conference "Methods and Concepts m European Quaternary Stratigraphy was held to take stock of the new developed concepts m Quaternary stratigraphy, to compare &fferent approaches and to evaluate the respectwe results m continental and marine environments The following papers, presented m this Issue, correspond to the theme "Methods for the study of stratlgraphlcal records ' They roughly indicate the average use of &fferent concepts developed m different dlsclphnes to Quaternary records Two biological objects are described m detad molluscs and pollen They are approached m two &fferent ways For the former, first of all by using a blogeographlcal approach based on the blome concept and secondly by trying to demonstrate the stratlgraphlcal value of mollusc assemblages m fluwal deposits For the latter, first of all by using a dynamxc approach to the vegetation cover of the middle mountain area of the Massif Central, France and secondly by using transfer functions to propose temperature and precipitation estimations from two long pollen sequences A last paper makes an evaluaUon of &fferent materml which can be ra&ocarbon dated and the rehablllty of the proposed dates, specmlly beyond 35,000 yr B P Ten years ago, European geologists who were dealing with Quaternary study met m Dijon to develop a common strategy concerning Quaternary stratigraphy (Chahne, 1980) The purpose was to homogenize and redefine a stratlgraphtcal approach accordmg to Hedberg's guide Three major recommendations were proposed (Paepe

The biotic evidence from a varied group of shallow-water organisms including mangroves, zooxanthellate corals (mainly reefal), and larger foraminifera suggests that sea surface temperatures at low latitudes during the Tertiary (from at least the Early Eocene to the Middle Miocene) were subtropical to tropical in nature, and similar to temperatures prevailing at low latitudes at the present day (20–28°C). In a recent paper (Shackleton, 1984), the suggestion is made (on the basis of oxygen isotope studies of foraminiferal shells) that low latitude sea-surface temperatures during the Palaeogene and much of the Neogene were invariably lower than those in similar regions today, with a stable temperature of around 18°C. This paper discusses the conflicting evidence for sea surface temperatures obtained from palaeontological and isotopic sources, and suggests that palaeotemperatures derived from some isotopic studies are too low to account for the distribution and diversity of many Tertiary tropical and subtropical biotas.

The aim of this paper is to determine the extent to which “raised” channel systems may be used as indicators of long-term paleohydrologic change, and hence of broader paleoenvironmental changes, in arid areas during the Cenozoic. The paper reviews the paleohydrologic significance of former drainage systems in arid areas, and demonstrates the application of paleohydrologic methods to the analysis of the long-term evolution of a complex series of exhumed, multistorey, raised channel systems in interior Oman. The paper discusses the range of possible autocyclic and allocyclic controls on changes in channel behaviour through time, as a means of establishing the paleoenvironmental significance of observed changes in paleochannel pattern, morphology, sedimentology and stability. The paper identifies some of the major allocyclic controls, including climatic changes, and particularly the seasonality, magnitude, frequency and distribution of rainfall events during the Cenozoic, together with the degree of continentality and hence the strength and persistence of arid wind systems. Base-level changes, due to eustatic fluctuations and/or tectonic activity, may also act to control long-term patterns of aggradation followed by large-scale landscaping lowering. However, long-term fan ageing associated with progressive aggradation and steepening of paleochannel systems, may also eventually lead to fanhead trenching, independent of any external controls. In addition, progressive expansion of the drainage network and resulting river capture, can lead to marked increases in water and sediment supplies to the fluvial system. The paper also emphasizes the difficulties involved both in differentiating the wide range of possible controls on paleohydrologic response, and also in developing an accurate and precise chronology for desert paleodrainage systems, and in their correlation with non-fluvial sedimentological sequences. The raised channel systems of interior Oman consist of heavily desert varnished chert-and/or ophiolite-rich gravels, dating from some time during the Plio-Pleistocene period. The paleochannels from sinuous gravel ridges rising The observed changes have resulted from a complex combination of both internally and externally generated environmental changes during the Cenozoic. Progressive extension of the drainage network on to the ophiolite massif of the mountain source area resulted in river capture and a concomitant increase both in paleodischarges and in supplies of ophiolitic sediments to the paleodrainage system. The early sinuous channels may have developed under a humid to sub-humid climate, in which perennial or seasonal flows allowed the distinct meander paleochannels to form. Ephemeral flows, characterized by flash flood regimes, were probably associated with the later distributary systems, which may reflect semi-arid to arid climatic conditions. The large-scale deflation of the interfluve sediments, which resulted in the eventual exhumation of the cemented, gravel-capped, multistorey paleochannel sequence, is also likely to have occurred during periods of marked continentality, probably during periods of low sea-level associated with the Quaternary glaciations.

The early Tournaisian (Carboniferous) stage represents a key episode in the evolution of vertebrates. It follows the end-Devonian Hangenberg extinction event, which led to a major perturbation to both terrestrial and aquatic vertebrate ecosystems, and resulted in a significant restructuring of assemblages. However, few faunal associ-ations of this age have been described, and our understanding of faunal turnover across the Devonian -Carboniferous boundary remains poor. In this paper, we present an analysis of coprolite material from early Tournaisian lacustrine facies at Celsius Bjerg on Ymer o in East Greenland, which overlies the world-famous latest Devonian tetrapod-bearing localities. Fifty-five coprolite specimens (defined as a single coprolite or a piece of shale containing coprolites) were analysed using propagation phase-contrast synchrotron micro -tomography (PPC-SR mu CT). Through a study of external morphology, shape and size combined with information about internal structures, we categorise coprolite morphotypes, and interpret their origin. Notably, we identify a greater number of coprolite morphotypes compared to vertebrate taxa known from skeletal material, indicating the existence of a cryptic ecosystem that has not yet been recovered as body fossils. Vertebrate diversity in the immediate aftermath of the end-Devonian extinction is inferred to have been higher than expected, and might have included transient faunal elements within an open system, perhaps involving marine basin connections. Our results show that coprolites offer an alternative fossil data source, revealing diversity that is otherwise not always captured by the skeletal record.

In this paper, we describe a 5500-year long core obtained from a lake in the Prealps of northern Italy to investigate the impact of human communities on the lacustrine environment. Specifically, we report micro-botanical proxies (upland and aquatic pollen, algae, cyanobacteria, dung spores, microcharcoal particles), sedimentary parameters (LOI steps, calcimetry, FTIR spectra) and nutrients (P forms, C/N and K) on paired samples in a high-resolution stratigraphy, dated by 14C AMS dating and tie point correlation. Independent archaeological evidence indicates the existence of lakeside settlements and farming in Bronze Age times from c. 4000 to 3300 cal yrs. BP. The impact of this Bronze Age village is recorded by an accumulation of plant detritus, pollen, charcoal and abundant wood and bone-derived ash. Intensive P mineralization by ash production was accompanied by the rapid burial of Pinorg, K, and microcharcoal. Correlated peaks of Porg and pasture plant pollen mark the contribution of animal husbandry to Porg lake sink. The nutrient flux produced by external catchment cropping contrasts with the internal flux discharged by prehistoric dwelling and in turn distinguishes domestic hearth production from a contribution by animal husbandry. Forest conditions and lake sedimentation returned to semi-natural baseline at the end of this 700-year long phase of Early to Middle Bronze Age settlement, but pollen proxies indicate that lake-side forests did not fully recover. Lake Lucone represents a key site, since it documents interactions between bronze Age settlements and related ecological impacts on both terrestrial environment and lacustrine sedimentation, as recorded in a continuous sequence, as well as the end of Bronze Age pile dwelling culture.

Altres ajuts: CERCA Programme/Generalitat de Catalunya The Guadalupian was a key epoch for the evolution of tetrapod faunas. It includes the earliest unambiguous occurrences of therapsids and stereospondyls (groups that later became dominant in terrestrial and freshwater environments, respectively) and the late Capitanian mass extinction event. The low-latitude faunas from this time interval, where sufficiently dated, comprise rare tetrapod body fossils whereas the most complete records are provided by ichnoassociations, especially coming from the Provence basins of France. In this paper, we revise the tetrapod ichnoassociation from the Pélitique Formation of the Le Luc Basin of Provence, identifying the following tetrapod ichnotaxa: Batrachichnus salamandroides (temnospondyls/lepospondyls), Capitosauroides talus comb. nov. (therocephalian therapsids), Dicynodontipus isp. (cynodont therapsids), Varanopus isp. (bolosaurian parareptiles), Hyloidichnus bifurcatus (captorhinomorph eureptiles) and Rhynchosauroides isp. (neodiapsid eureptiles). According to our revised ichnotaxonomy and stratigraphic correlations, we date the Pélitique Formation as late Capitanian and assign its tetrapod ichnoassociation to the newly defined Association V (Dicynodontipus sub-biochron of the Erpetopus biochron). The Pélitique Formation ichnoassociation shows a typical composition for a post-dinocephalian extinction ichnofauna, as shown by preliminary multivariate statistics on Guadalupian-Lopingian tetrapod ichnoassociations. It is similar to the contemporaneous skeletal faunas described from the mid- to high-latitude sites of Russia and South Africa and is arguably the earliest evidence of post-dinocephalian extinction recovery at low-latitudes. Our results confirm the global and abrupt impact of the late Capitanian terrestrial mass extinction and the subsequent recovery in the low-latitude realm. This extinction was probably time-equivalent with a global benthic marine mass extinction, and both events may have been linked to climatic perturbation caused by the Emeishian volcanic activity in China, which reached its peak around 260 Ma.