Fossil Associations Research Articles

Biostratigraphy of Turonian to (?)Coniacian Platform Carbonates: A Case Study from the Island of Cres (Northern Adriatic, Croatia)

The shallow marine carbonate deposits on the island of Cres, overlying deeper-water Cenomanian–Turonian limestones, are characterized by an assemblage of rudists, benthic foraminifera, and associated microfossils. The paucispecific character of the fossil association suggests deposition in shallow areas of a carbonate platform, with low current-energies and restricted circulation. Similar assemblages indicating similar palaeoenvironments, are common in the Upper Cretaceous deposits of the Adriatic Carbonate Platform and adjacent areas.The assemblage of rudists (hippuritids) and microfossils indicate the Turonian to (?)Coniacian age of the investigated carbonate succession. The biostratigraphic importance of the so-called “primitive” hippuritids within the micropalaeontologically poorly defined biostratigraphy of deposits of this age, is accentuated.

Morphological taphonomic transformations of fossil bones in continental environments, and repercussions on their chemical composition

The aim of this paper is to provide a summary of structural or surface modifications of vertebrate bone remains in continental palaeoenvironments that may have repercussions on their chemical composition. Both before and after burial, a different set of physical, chemical and biological agencies may produce modifications of the bone morphological structure and/or bone chemical composition. Several of these morphological modifications are diagnostic of particular agents, which otherwise may not be noticed or identified in a fossil association. In order to understand diagenesis, those events that occurred before final burial have to be considered, as they may strongly modify the bone morphological structure and influence post–burial changes.

Amphibians and reptiles from the Early Miocene of the Bardenas Reales of Navarre (Ebro Basin, Iberian Peninsula)

The Lower Miocene deposits of the Bardenas Reales of Navarre (NW Ebro Basin, northern Iberian Peninsula) have yielded a diverse vertebrate fauna, including remains of amphibians and reptiles. These remains occur in several localities in the Tudela Formation. The fossiliferous levels belong to the Biozones MN2b-3 (Biozones Z-A of the Ramblian, i.e., Late Aquitanian to Early Burdigalian in age). The amphibians and reptiles represent at least 13 out of 37 vertebrate species. Amphibians consist of a salamandrid urodele and two or three anurans. All the turtles are cryptodirans and consist of the chelydrid Chelydropsis apellanizi, the testudinids Ptychogaster ( Temnoclemmys) bardenensis and Ptychogaster ronheimensis, and a Trionychinae indet. Squamates are represented by the anguid lizard Ophisaurus sp., a non-anguid lacertilian, an amphisbaenian, the erycine boid? Eryx sp., and indeterminate colubrids. Crocodilian remains are assigned to the basal alligatoroid Diplocynodon sp. The fossil associations of the Bardenas Reales of Navarre suggest that the vertebrates lived in the centre of an endoreic basin with stretches of water under intertropical to subtropical climatic conditions.

Ichnology, Sedimentology and Paleontology of Eocene Calcareous Paleosols From a Palustrine Sequence, Argentina

Other| February 01, 2002 Ichnology, Sedimentology and Paleontology of Eocene Calcareous Paleosols From a Palustrine Sequence, Argentina RICARDO N. MELCHOR; RICARDO N. MELCHOR 1CONICET & Universidad Nacional de La Pampa, Av. Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina Search for other works by this author on: GSW Google Scholar JORGE F. GENISE; JORGE F. GENISE 2CONICET & Departamento de Icnología, Museo Paleontológico “Egidio Feruglio”, Av. Fontana 140, 9100 Trelew, Chubut, Argentina Search for other works by this author on: GSW Google Scholar SERGIO E. MIQUEL SERGIO E. MIQUEL 3CONICET & Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, 1405 Buenos Aires, Argentina Search for other works by this author on: GSW Google Scholar PALAIOS (2002) 17 (1): 16–35. https://doi.org/10.1669/0883-1351(2002)017<0016:ISAPOE>2.0.CO;2 Article history accepted: 05 Jul 2001 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation RICARDO N. MELCHOR, JORGE F. GENISE, SERGIO E. MIQUEL; Ichnology, Sedimentology and Paleontology of Eocene Calcareous Paleosols From a Palustrine Sequence, Argentina. PALAIOS 2002;; 17 (1): 16–35. doi: https://doi.org/10.1669/0883-1351(2002)017<0016:ISAPOE>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search Abstract Integrated analysis of the ichnology, sedimentology, geochemistry, and fossil content of three trace fossil-bearing calcareous paleosols from the early Eocene Gran Salitral Formation is used to reconstruct the detailed paleoenvironmental and paleoecological setting of this insect-dominated ichnofossil association. This continental sequence, located in southwestern La Pampa province (Argentina), is composed of palustrine marls and minor lacustrine mudstones and sandstones arranged in shallowing-upward cycles. The ichnologic association is the first comprehensively described from a palustrine sequence and could be used for future comparisons with other similar assemblages. The ichnofauna is dominated by bee cells, Celliforma germanica, C. roselli, and Rosellichnus isp.; Teisseirei barattinia, an insect trace fossil that is redescribed and recorded for the first time outside its type locality; Taenidium barretti; and Skolithos linearis. The ichnologic association also includes ovoid structures, ornamented burrow fillings, and plant trace fossils (rootlets, rhizoliths, and a tree / shrub stump). Abundant freshwater (Pomacea sp.) and terrestrial gastropods (Plagiodontes spp., Bostryx sp., and Bulimulus sp.) are used to characterize the paleoenvironmental setting. The weakly developed paleosols are interpreted as Inceptisols, developed in a low-gradient lake margin periodically exposed to pedogenesis with low (probably saline) vegetation and sparse shrubs. They developed under a semi-arid and warm climate (mean annual temperature higher than 20°C). Short saline / alkaline conditions were prevalent during lake lowstands, accompanied by incipient karst development. The association of trace fossils is attributed provisionally to the Coprinisphaera ichnofacies, although its distinctive features and recurrence in time and space may deserve recognition as a separate ichnofacies. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Late Pliocene fossils of Ecuador and their role in the development of the Panamic bioprovince after the rising of Central American Isthmus

Studies carried on in the last several years allow us to date the Canoa Formation as Late Pliocene. The rich paleontological record (foraminifers, mollusks, and otoliths) allowed us to outline a first articulate picture of the biogeographic relationships in the tropical eastern Pacific during the Plio-Pleistocene. The mollusk fauna shows a Panamic connotation, as the majority (88.7%) of the extant species are present between the Gulf of California and the coasts of Ecuador or northern Peru. Benthic foraminifers assemblages indicate a temperate character with a certain affinity with the Mexican Pacific microfauna. More than 7000 otoliths have been found in the Canoa Formation that are attributed to 105 taxa of 46 fish families. Only 65% of the fossil association is living today along the Ecuadorian coasts, while the association as a whole shows closer relationships with the extant Californian fish community (about 80%). In particular, a conspicuous group of fishes (15 taxa) today spread in the boreal East Pacific (from Oregonian to Californian Province or limited only to the Californian area) has been recorded in the Canoa Formation. We named these taxa "Californian guests." After the rising of the Central American Isthmus, climatic variations may have caused changes in the pattern of surface currents and (or) activated coastal upwelling cells, supporting the diffusion of a part of the boreal biota toward more southern areas. At the present state of knowledge, both proximal causes seem to be compatible with the data presented.

Trace fossil associations in the Swedish Mickwitzia sandstone (Lower Cambrian): Did trilobites really hunt for worms?

The spatial and temporal associations between Cruziana, trace fossils dug by foraging trilobites, and back filled burrows made by infaunal “worms” in a Lower Cambrian sandstone are described and discussed. In three large slabs and several smaller pieces, all from the same bedding plane in the lowermost part of the Mickwitzia sandstone (File Haidar Formation) at Kinnekulle, Västergötland, Sweden, Cruziana and worm burrows coincided more frequently than would be expected by chance. Overall, however, the association was weak and independent of the size of the worm trace. In 24 out of 29 cases, the worm burrow had deformed the Cruziana, implying that the arthropod was first on the spot. No clear case of the opposite situation was found. It is concluded that for an unknown reason the infaunal worms preferentially dug in places which had been visited earlier by foraging trilobites, or, possibly, that worms and trilobites preferred to dig in the same spots independently of each other. There is no evidence from this surface that the trilobites had been searching for worms or predated on them.

Upper Triassic (Keuper) non-marine trace fossils from the Haßberge area (Franconia, south-eastern Germany)

Various trace fossils from the Hassberge Formation and the Lowenstein Formation (Middle Keuper, Upper Triassic) of the Hasberge region are described. Twenty-three different forms have been identified, 17 of which are named, includingCruziana pascens n. isp.,Lockeia cunctator n. isp., andRusophycus versans n. isp.Lockeia siliquariaJames, 1879,L. amygdaloides (Seilacher, 1953),L. triangulichnusKim, 1994, andL. elongata (Yang, 1984) are revised and synonymized under the oldest available name,L. siliquariaJames, 1879.Rusophycus eutendorfensis (Linck, 1942) andR. carbonariusDawson, 1864 are revised. The diagnosis ofPolykladichnusFursich, 1981 is emended, and a diagnosis forHelminthoidichnitesFitch, 1850 is given for the first time. Among the described ichnotaxa,Skolithos ispp.,Rusophycus carbonarius, andTaenidium barretti are the most common forms. The trace fossil association is typical of theScoyenia ichnofacies, which indicates non-marine, periodically or completely inundated environments, such as floodplains and lake margins. Two palaeoichnocoenoses are identified. One ichnocoenosis, dominated byCruziana problematica, cf.Polykladichnus isp., andSkolithos isp. B characterizes margins of trough cross-bedded sandstones. Another ichnocoenosis, dominated byRusophycus versans n. isp.,Taenidium barretti,Scoyenia gracilis andSkolithos isp. A is related to ephemeral lake deposits. Taxonomic recommendations for the use of hitherto described and figured invertebrate Keuper trace fossils from Germany are given.

Stratigraphie sequentielle de l'Aptien du sous-bassin de Galve (Province de Teruel, NE de l'Espagne)

Abstract A correlation is established in a north-south transect based on continuous outcrops. Considering the different reference surfaces and the geometry, three major depositional sequences can be distinguished which can be subdivided into a complex arrangement of parasequences. These third-order sequences are composed of a lower retrogradational and an upper progradational trends. The first sequence contains orbitolinid bioaccumulations in the retrogradational trend and oolitic-bioclastic shoals in the progradational trend. The second sequence exhibits, from bottom to top, a transgressive, a regressive and a forced-regressive trends. Ammonite-rich marls characterise the transgressive trend, whereas bioconstructions rich in coral-chaetetids-microbialites are abundant in both regressive and forced-regressive trends. The maximum flooding of this sequence is widely distributed across the whole Iberian platform. Finally, the third sequence shows the installation of homogeneous rudistid bioaccumulations in a retrogradational and a progradational trends. Each major sequence boundary marks a community replacement, whose respective fossil associations are dominated by (1) orbitolinids, (2) corals-microbialites, (3) corals-chaetetids-microbialites, and (4) rudists.

Análisis tafonómico de moluscos holocenos en el área costera del Estuario de Bahía Blanca, Argentina

At the south west of the Buenos Aires province, Argentina, on the northern coast of the Bahía Blanca Estuary, sand-shell ridges sub-parallel to the coastline generated during the Holocene transgression-regression were deposited. These structures are composed mostly of coarse to medium sand and a high proportion of molluscs shells (19 species of bivalves and 16 species of gastropods). For this study three taxa from the fossil association located in the ridges (Brachidontes rodriguezi, Tegula patagonica and Crepidula aculeata) were selected and the mechanisms of taphonomic alteration that affected them were qualified. By means of ternary taphograms the variation of five taphonomic attributes (bioerosion, encrustation. fragmentation. wear and dissolution) was established. It has been determined that the bioestratinomic processes are subordinated to the fossildiagenetic mechanisms, where dissolution has left a series of taphonomic signatures. Based upon the taphonomic attributes of the fossil association a high stand sea level cycle with an important contribution of storm waves that affected the biogenic production area were established as a representation of the paleoenvironmental evolution.

Echinoid Spines from the Anisian (Middle Triassic) of Qingyan, South‐ western China

Echinoid remains from the Triassic of China are described for the first time. The Middle Triassic of Qingyan in Guizhou Province, south‐western China, has yielded nine taxa of primary spines; seven of these come from the lower Upper Anisian. Because all of the spines are disarticulated, the material is treated only parataxonomically. ‘Cidaris’ lineola (Bather) and ‘Cidaris’ wissmanni (Desor) are species originally described from the alpine Triassic of Europe. ‘Cidaris’ bangtoupoensis sp. nov., ‘Cidaris’ wachangpoensis sp. nov., ‘Cidaris’ venustespinosa sp. nov., ‘Cidaris’ fangchui sp. nov., ‘Cidaris’ gu sp. nov., ‘Cidaris’ mafengpoensis sp. nov. and ‘Cidaris’ sp. A are so far known only from Qingyan. Palaeoautecological interpretations based on the shapes of the spines fit well with the fact that the echinoids from Qingyan are part of highly diverse fossil associations which represent the remains of communities that lived in a protected, shallow‐marine, stable soft‐bottom habitat. The rather high diversity of the echinoid spines in terms of the number of both taxa and general types of shape shows that the echinoids, after nearly becoming extinct at the end of the Palaeozoic, began a new phase of adaptive radiation in the Anisian at the latest.

High-Resolution Architecture and Paleoecology of an Active Margin, Storm-Flood Influenced Estuary, Quinault Formation (Pliocene), Washington

Other| December 01, 2000 High-Resolution Architecture and Paleoecology of an Active Margin, Storm-Flood Influenced Estuary, Quinault Formation (Pliocene), Washington KATHLEEN A. CAMPBELL; KATHLEEN A. CAMPBELL 1Department of Geology, University of Auckland, Private Bag 92019, Auckland, New Zealand Search for other works by this author on: GSW Google Scholar ELIZABETH A. NESBITT ELIZABETH A. NESBITT 2Department of Geological Sciences and Burke Museum of Natural History and Culture, Box 353010, University of Washington, Seattle, WA 98195-3010 Search for other works by this author on: GSW Google Scholar PALAIOS (2000) 15 (6): 553–579. https://doi.org/10.1669/0883-1351(2000)015<0553:HRAAPO>2.0.CO;2 Article history accepted: 08 Aug 2000 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation KATHLEEN A. CAMPBELL, ELIZABETH A. NESBITT; High-Resolution Architecture and Paleoecology of an Active Margin, Storm-Flood Influenced Estuary, Quinault Formation (Pliocene), Washington. PALAIOS 2000;; 15 (6): 553–579. doi: https://doi.org/10.1669/0883-1351(2000)015<0553:HRAAPO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyPALAIOS Search Advanced Search Abstract An exhumed Pliocene estuarine sequence is preserved in exquisite detail in the Quinault Formation of coastal western Washington. The thick fill of the Quinault estuarine basin (∼700 m) represents a single transgressive-regressive system that was punctuated by subduction-related tectonic events, and may reflect erosion and sediment accumulation during accelerated uplift of the Olympic Mountains in the Pliocene. Sedimentation patterns in the ancient Quinault estuary were influenced strongly both by floods on the paleo-Quinault River, and by storm waves on the high-energy, open Pacific coast. Body fossils were derived from both marine and brackish faunal elements. Trace fossil suites indicate that the benthos flourished in the fluctuating physicochemical conditions of an estuary in dynamic equilibrium. An estuarine-specific trace fossil, a new ichnospecies of Psilonichnus that is attributed to burrows of the mud shrimp Upogebia pugettensis, is restricted to inlet-mouth, muddy sandstone facies. The marine-marginal marine transition is well-preserved in Quinault estuarine strata (exposed in the Point Grenville and Cape Elizabeth areas), as evidenced by: (1) distinctive sedimentologic signatures characteristic of lower shoreface, estuarine mouth, central basin, tidal creek/flat, and fluvial subenvironments; and, (2) systematic changes in trace fossil associations in the up-estuary direction, from Skolithos ichnofacies elements to a mixed Skolithos-Cruziana assemblage to Glossifungites associations with rhizome phytoburbation. Hence, Quinault strata record a classic tripartite division of an ancient estuarine system, allowing a fine-scale delineation of subenvironments in an active tectonic regime. You do not currently have access to this article.

Sequence analysis of the Ecca--Beaufort contact in the southern Karoo of South Africa

Sequence analysis of the Ecca—Beaufort boundary in the southern Karoo Basin has revealed three separate facies associations spanning the stratigraphic interval between the top of the Fort Brown Formation and the lowermost maroon mudrocks of the Beaufort Group. This sequence was deposited in prodelta, delta front, and delta plain environments respectively. The lithological contact between the rocks deposited in the delta front and delta plain represents the palaeoshoreline, and occurs only once in the stratigraphic sequence, suggesting a continuous normal regression from Ecca to Beaufort times. This diachronous shoreline is associated with deltaic progradation within ahighstand systems tract. Sediment deposition was mainly a result of ephemeral flash floods, but perennial rivers also flowed from melting ice-capped highlands to the palaeosouth. Two separate fossil associations have been recognized and correlate with the lithological subdivisions. The lower fossil assemblage occurs in the Fort Brown andWaterford formationsand is characterized by silicified wood, comminuted plant material, and fish scales. The upper association occurs only in the lower Beaufort Group and includes in situ equisitalean, and well-preserved Glossopteris plant fossils and tetrapods of the Eodicynodon Assemblage Zone. The Beaufort—Ecca boundary coincides with the position of the palaeoshoreline. This lithological contact also marks achange in depositional style and palaeontological character between the two groups. The new placementof the boundary is some 300— 650m below the presently mapped contact in the south of the basin.

Insect Trace Fossil Associations in Paleosols: The Coprinisphaera Ichnofacies

Fil: Genise, Jorge Fernando. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Secretaria de Industria y Mineria. Servicio Geologico Minero Argentino. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Cientificas y Transferencia Tecnologica de La Rioja; Argentina

Associations of Vertebrate Skeletal Concentrations and Discontinuity Surfaces in Terrestrial and Shallow Marine Records: A Test in the Cretaceous of Montana.

Although lags of bones and teeth are commonly cited criteria for marine unconformities, the consistency of the association of vertebrate fossils and discontinuity surfaces, as well as the taphonomic (postmortem) controls on this relationship, are poorly understood. A field test across fluvial, paralic, and shallow marine facies in the Campanian Two Medicine and Judith River formations of Montana indicates that the distribution of vertebrate skeletal concentrations is poorly correlated with the inferred durations of erosional and omissional hiatuses. Instead, vertebrate concentrations associated with discontinuities of all durations tend to be patchy and closely track the abundance of fossil material in underlying and lateral facies. Based on the analysis of 83 measured sections, we found first that erosional bases of channels and minor scours within channels yield vertebrate lags; tidally influenced fluvial deposits are more productive than are "upland" fluvial deposits. Second, erosional shoreface ravinements and their correlative transgressive marine flooding surfaces (fourth-order sequence boundaries) have well-developed vertebrate lags only along segments that cut across older shoreface deposits. Third, a nonerosional, widely traceable discontinuity, which is interpreted as the nonmarine extension of a 75.4-Ma third-order transgressive surface, is completely lacking in vertebrate concentrations. Despite being unfossiliferous itself, this discontinuity does mark a regional change in the richness of the vertebrate fossil record, with overlying beds characterized by a much greater abundance of skeletal material. Fourth, a laterally extensive set of erosional surfaces, embedded within multistory fluvial sandstone sheets, is the nonmarine extension of an 80-Ma third-order sequence boundary in the marine basin and lacks vertebrate concentrations. The strong dependence of vertebrate lag development on preexisting local sources of skeletal material rather than on the magnitude of the erosional vacuity or the duration of the hiatus contrasts with skeletal concentrations of invertebrates in marine successions, where exhumation is generally much less important than the production of new elements during the hiatus. These findings provide a guide to prospecting productive fossil horizons in terrestrial records and underscore fundamental differences in the ways in which bioclastic material accumulates in terrestrial and shallow marine settings, the qualities of paleobiologic data derived from such concentrations, and the relative reliabilities of skeletal material as cues to stratigraphically significant discontinuities.

Implications of the avian fauna for paleoecology in the Early Pleistocene of the Iberian Peninsula

The aim of this paper is to reconstruct the landscape and climate during the formation of the Lower Pleistocene TD6 layer at Gran Dolina, Atapuerca. Habitat preferences and phenetic behavioural spectra of fossil birds are reconstructed using comparisons of fossil bird assemblages with modern avian communities. This method is based upon the phenology (seasonality and breeding status) of each species for both the fossil association and modern communities. The results indicate that more open country and wetter conditions prevailed during the early Pleistocene than were previously inferred.

A coral-microbialite patch reef from the late jurassic (florigemma-Bank, Oxfordian) of NW Germany (Süntel mountains)

Anin situ Oxfordian patch reef from the Suntel hills (florigemma-Bank, Korallenoolith, NW-Germany) is described. It is composed of an autochthonous reef core overlain by a ‘parautochthonous’ biostrome. The exposed reefal area amounts to about 20 m in lateral and up to 4 m in vertical direction. Nearly all major marine reefal fossil associations from the Tethyal realm are present.

An Early Aptian ichnofossil assemblage zone in southern Israel, Sinai and southwestern Egypt

The Amir Formation, a lower Cretaceous clastic tidal deposit in southern Israel and Sinai (Egypt), displays several forms of endobenthic ichnofauna, dominated by burrows of polychaetes and anemone-like or crustacean animals. The ichnofossils occur in fine-grained sandstones with major traces of Diplocraterion, Skofithos, Polykladichnus and Conichnus. Of particular interest is a zone at the top of the formation, where the sandy sediments are incised by fossil tidal channels that locally show traces of these burrowing organisms. A similar ichnofacies of the same age occurs across the Gulf of Suez in south and southwestern Egypt. The wide extent of this burrowed zone makes it a useful stratigraphical marker. Also of significance is the association of the trace fossils with well-preserved sand bars and tidal channels, which enables study of their paleoecology and provides another aspect in the interpretation of the tidal model.

Recent benthic foraminiferal associations and ecology of the Scotia Sea and Argentine Basin

We investigated 88 surface sediment samples taken with a multiple corer from the southwestern South Atlantic Ocean for their live (Rose Bengal stained) and dead benthic foraminiferal content. Using Q-Mode Principal Component Analysis six live and six dead associations are differentiated. Live and dead association distributions correspond fairly well; differences are mainly caused by downslope transport and selective test destruction. In addition, four potential fossil associations are calculated from the dead data set after removal of non-fossilizable species. These potential fossil associations are expected to be useful for paleoceanographic reconstructions. Environments are described in detail for the live and potential fossil associations and for selected species. Along the upper Argentine continental slope strong bottom currents control the occurrence of live, dead and potential fossil Angulogerina angulosa associations. Here, particles of a high organic carbon flux rate remain suspended. Below this high energy environment live, dead and potential fossil Uvigerina peregrina dominated associations correlate with enhanced sediment organic carbon content and still high organic carbon flux rates. The live A. angulosa and U. peregrina associations correlate with high standing crops. Furthermore, live and dead Epistominella exigua-Nuttallides umbonifer associations were separated. Dominance of a Nuttallides umbonifer potential fossil association relates to coverage by Antarctic Bottom Water (AABW) and Lower Circumpolar Deep Water (LCDW), above the Calcite Compensation Depth (CCD). Three associations of mainly agglutinated foraminifera occur in sediments bathed mainly by AABW or CDW. A Reophax difflugiformis association was found in mud-rich and diatomaceous sediments. Below the CCD, a Psammosphaera fusca association occurs in coarse sediments poor in organic carbon while a Cribrostomoides subglobosus-Ammobaculites agglutinans association covers a more variable environmental range with mud contents exceeding 30%. One single Eggerella bradyi-Martinottiella communis association poor in both species and individuals remains from the agglutinated associations below the CCD if only preservable species are considered for calculation.

Palynofacies analysis of sediments from the Côte d'Ivoire-Ghana transform margin: Preliminary correlation with some regional events in the Equatorial Atlantic

Analyses of the palynofacies and sporomorph thermal alteration indices (TAI) of sediments from Ocean Drilling Program (ODP) Sites 959 to 962 in the Côte d'Ivoire-Ghana Transform Margin, West Africa were undertaken to (1) determine the source and depositional conditions of the organic matter in the sediments, (2) refine a paleobathymetric curve derived from other data for Site 959, which drilled the most continuous sedimentary sequence from Pleistocene to Albian and (3) interpret the paleothermal history of the area. Twelve types of dispersed organic matter were identified: amorphous organic matter (AOM), marine palynomorphs, algae, resins, black debris, yellow-brown fragments, black-brown fragments, cuticles, plant tissue, wood, sporomorphs and fungi. The relative abundances of these organic matter components at each site were analyzed using cluster analysis, resulting in the identification of seven palynofacies assemblages at Site 959, five each at sites 960 and 961, and four at Site 962. Amorphous organic matter (which is chiefly marine derived), black debris and wood have played the most significant role in defining palynofacies assemblages. The palynofacies assemblages show some correlation with lithologic units, sediment sources and depositional environments. Previous palynofacies studies in passive margins have demonstrated that changes in the ratio of AOM to terrestrial organic matter are related primarily to proximal-distal positions of depositional environments relative to the shoreline. However, this assumption does not always hold true for a transform margin where tectonic factors play an important role in the organic matter distribution, at least in the early stages of evolution. Lithofacies, CCD paleodepths for the North Atlantic, trace fossil association, benthic foraminifera and palynofacies data were the criteria used for reconstructing a paleobathymetric curve for Site 959. A cyclicity in the organic matter distribution of the Upper Miocene to Lower Pliocene pelagic sediments could be related to fluctuations in productivity of biosiliceous and calcareous organisms, and sedimentation rates. A drastic increase in the amount of AOM and a decrease in black debris and wood in the carbonate and clastic rocks (Lithologic Unit IV) overlying the tectonized Albian sediments (Lithologic Unit V) at Sites 959 and 960 coincide with the presence of an unconformity. Qualitative color analysis of palynomorphs was undertaken for all sites, although the main focus was on Site 959 where detailed organic geochemical data were available. At Site 959, TAI values indicate an immature stage of organic maturation (<2) down to the black claystones of Lithologic Unit III at about 918.47 mbsf. Below this, samples show an increase with depth to a moderately mature stage (>2 except for the claystone samples between 1012.52 and 1036.5 mbsf, and one limestone sample at 1043.4 mbsf), reaching peak levels of 2.58 to 3.0 in the tectonized Albian sediments below the unconformity. These TAI values show a positive correlation with the T max values derived from Rock-Eval pyrolysis data. The highest values recorded in the basal tectonized units at all the sites (Sites 960–962 have mean values between 2.25 and 3.13) may be related to high heat flow during the intracontinental to syntransform basin stage in the region.

Palaeoenvironmental andstratigraphic aspects of animal traces and plant remains in Spanish Permian red beds (Peña Sagra, Cantabrian Mountains, Spain)

Various vertebrate and invertebrate traces and plants remains have been discovered in the Permian of Pico Paraes (Cantabrian Mountains). They occur in the Sagra Formation, a 400 m thick unit consisting of a vertical alternation of channels with conglomeratic sandstones and fossiliferous red siltstones with a caliche horizon at the top. The most common trace is Hyloidichnus major which is attributed to approximately 50 cm long Captorhinomorphs. Other tracks provisionally assigned to Limnopus could also indicate the presence of Temnospondyls. The bedding planes with traces also show some tracks of Isopodichnus cf. minutus which is ascribed to small triopsid crustaceans. Like the footprints, these are sometimes cut off by insect burrows like cf. Steinichnus, Scoyenia gracilis, Ancorichnus sp. or Skolithos. These fossiliferous levels have also yielded conchostracans, unidentifiable plant stems and a rather well-preserved frond of Supaia sp. The fossil association and sedimentological features suggest that the Sagra Formation is a floodplain deposit; the water depth was limited and fluctuated. Longer drier intervals also occurred. The vegetation was meso-xerophilous. The occurrence of the ichnopopulation Hyloidichnus major and Supaia in the Permian of France (Lodève basin) and North America (Grand Canyon, U.S. A) suggests that the Sagra Formation can be correlated with the Rabejac Formation of the Lodève basin. Based on comparisons with the Supaia-bearing Hertmit Shale, the Sagra Formation might be dated as early Leonardian, or even Artinskian when the Leonardian can indeed correlated with the Artinskian + Kungurian.