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EN
We provide the first reports of some rare trace fossils from the middle Turonian (Upper Cretaceous) of the Sudety Mountains (SW Poland, Upper Nysa Kłodzka Graben, Długopole Górne Quarry). These include burrows ?Ancorichnus isp., Asterosoma cf. ludwigae Schlirf, 2000, Asterosoma isp., cf. Phycodes isp., Dactyloidites ottoi (Geinitz, 1849), Funalichnus strangulatus (Fritsch, 1883), Phycodes cf. palmatus Hall, 1852, cf. Phycodes, Phycosiphon incertum Fischer-Ooster, 1858, ?Phycosiphon isp., Planolites beverleyensis (Billings, 1862) and borings Entobia isp. Some body fossils, bivalves ?Brachidontes sp., Lima canalifera Goldfuss, 1836, Pinna (Pinna) cretacea (Schlotheim, 1813) and Rhynchostreon suborbiculatum (Lamarck, 1801) are also reported. The trace fossil assemblage indicates a distal Skolithos ichnofacies and proximal Cruziana ichnofacies, which characterize a proximal and distal lower shoreface setting respectively. Sedimentation of the middle Turonian sandstones took place in a shallow epicontinental sea of normal salinity and a soft substrate, which was well-oxygenated under low-moderate hydrodynamic conditions. The presence of the oyster Rhynchostreon in the deposits studied suggests the influence of a warm Tethys Ocean.
EN
Seven Middle Miocene (Upper Badenian to Lower Sarmatian) sedimentary sections of the Central Paratethys, two from the Polish Carpathian Foredeep Basin (PCFB) and five from the Eastern Carpathian Foreland Basin (ECFB) of Romania and the Republic of Moldova have been analysed micropalaeontologically to better constrain the Badenian-Sarmatian Extinction Event, characterized by significant taxonomic impoverishment of both foraminifers and ostracods. Ourstudies show significant palaeoenvironmental changes in the basin including depth, salinity, oxygenation, and organic matter flux. The occurrence of moderately diverse planktonic foraminifera (Globigerina, Globigerinita, Globorotalia, Trilobatus, Orbulina, Velapertina) in the Upper Badenian deposits of the PCFB as well as in the ECFB and their rarity in the lowermost Sarmatian indicate an almost fully marine environment during the latest Badenian, followed by a significant regression and possible appearance of much more restricted marine conditions across the boundary. The taxonomic composition of the Sarmatian foraminifera, ostracoda and calcareous nannofossils indicate that during this interval the salinity fluctuated strongly, with the water regime varying from brackish to normal marine. In addition, the identified micropalaeontological assemblages identified show palaeoenvironmental similarity across different basins of the Central Paratethys. This supports a hypothesis of possible connections during the latest Badenian between different areas of the Central Paratethys, as well as of the existence of a gateway between the Central Paratethys and the Mediterranean realm.
EN
In the sandstones and conglomerates of the Idzików Conglomerate Member (Coniacian), exposed in the Idzików Quarry (SW Poland, Upper Nysa Kłodzka Graben), a moderately diverse assemblage of trace fossils has been recognized. The trace fossils include Arenicolites isp., Asterosoma isp., ?Bergaueria isp., Cylindrichnus isp., Conichnus conicus, Curvolithus simplex, Dactyloidites ottoi, Diplocraterion parallelum, ?Diplocraterion isp., Gyrochorte isp., Gyrophyllites aff. kwassizensis, Macaronichnus segregatis, Ophiomorpha nodosa, Ophiomorpha isp., ?Palaeophycus isp., ?Rhizocorallium isp., Rosselia isp., ?Scolicia isp., Teichichnus isp. and Thalassinoides isp. Escape traces (fugichnia) and some unidentified trace fossils also were found. The following ichnoassociations are distinguished: (IA1) Ophiomorpha-Cylindrichnus, (IA2) Asterosoma-Conichnus and (IA3) Ophiomorpha- Arenicolites. IA1 probably represents a mixture of the impoverished proximal Cruziana ichnofacies and the distal Skolithos ichnofacies, which points to the lower, weakly storm-affected shoreface. IA2 is interpreted as the archetypal Skolithos ichnofacies (opportunistic colonization of tempestite beds) with some elements of the Cruziana ichnofacies (bioturbated, fair-weather background deposits) in the middle, moderately storm-affected shoreface. IA3 is assigned to the archetypal Skolithos ichnofacies, which indicates the upper shoreface-foreshore settings. The trace-fossil evidence implies that the Upper Cretaceous succession was deposited in a shallow, open basin with good oxygenation of the sea floor and normal salinity, under low- to moderately high-energy hydrodynamic conditions. On the basis of ichnological and sedimentological analyses, the deposits studied originated in a system of fan-delta and shallow-shelf settings with common transitional-proximal tempestites. They were deposited in the eastern part of the Upper Nysa Kłodzka Graben during the Coniacian regression.
EN
Borehole K-1 is an exploratory well that was drilled in the North Makassar Basin (West Sulawesi) in 2011. Gas chromatography (GC) and gas chromatography-mass chromatography (GC-MS) analyses have been conducted on extracts from well cuttings from the Paleogene to Neogene interval in order to investigate the characteristics of biomarkers present. Although the well was drilled with oil-based mud and gas chromatographic analysis reveals that the alkane fractions are heavily contaminated, detailed investigation of biomarkers in these rock extracts and comparison with biomarkers in the oil-based mud has revealed that, while there are hopane and sterane biomarkers in the mud, there are also a discrete set of biomarkers that are indigenous to the rocks. These include oleanane, bicadinanes, taraxastane and other higher-plant-derived triterpanes. The presence of these compounds in environments that range from bathyal to marginal marine and even to lacustrine, shows the extent of reworking of terrestrial material into aquatic settings in this region during the Paleogene and Neogene and provides further evidence of a predominance of terrestrial material, even in deep-marine settings, with little ‘in-situ’ material noted. These findings have important implications for the use of biomarkers as indicators of palaeoenvironment in both source rocks and oils.
EN
The Upper Turonian to Middle Coniacian (Upper Cretaceous) succession of the Babadag Basin (North Dobrogea, Romania) constitutes an apparently continuous fossiliferous carbonate succession. The presence of moderately rich inoceramid, ammonite and foraminiferal assemblages allows for the application of a precise biostratigraphic subdivision. The palaeoenvironmental conditions and evolution of the Babadag Basin during the Late Turonian-Middle Coniacian are inferred using microfacies analysis and foraminiferal spectra. Together, these suggest the Turonian-Coniacian Badabag Basin reflects relatively shallow-water conditions in a near-shore environment, punctuated by two regression events in the Late Turonian and in the Middle Coniacian.
EN
A new ichnogenus and ichnospecies Rosarichnoides sudeticus is proposed for a large, exceptionally well-preserved crustacean burrow, which has been found in the Upper Cretaceous (Coniacian) Quadersandstein of the North Sudetic Synclinorium (Czaple quarry). Some of its specimens have been assigned to Thalassinoides saxonicus (Geinitz, 1842). It is unbranched, a characteristic rosary-shaped trace fossil, which consists of alternating chambers (swellings) and constrictions. The burrow is without any wall and usually lack ornamentation and has a passive fill. It should be included in ophiomorphid group sensu Bromley (1996). This unique finding resembles modern crustacean burrows produced by shrimps or crabs. Additionally, Thalassinoides paradoxicus (Woodward, 1830), the starfish Astropecten scupini Andert, 1934, the inoceramids Inoceramus kleini Müller, 1888 and Inoceramus sp. were found in the same sandstones. The trace fossils are indicative of the archetypal Skolithos ichnofacies that is typical of foreshore to middle shoreface settings.
EN
The Sarcheshmeh and Sanganeh formations are the Lower Cretaceous deep marine sequences of the Koppeh-Dagh sedimentary basin, which revealed a diverse assemblage of dinoflagellates. The paper discusses palynostratigraphy, palynofacies and palaeoenvironment of these rock units in a borehole drilled in the eastern part of this basin. Ninety-five ditch-cutting samples were prepared and studied palynologically, which resulted in recognition of 76 species of dinoflagellate cysts belonging to 29 genera. The recorded assemblages are in accordance with the Odontochitina operculata Zone suggesting a Barremian?–Aptian age for the formations. Palynological data extracted led to identification of five palynofacies types based on the categories of Tyson (1995). These indicate a marginal, proximal and distal shelf environment of deposition. The obtained data from calculated palaeoecological factors revealed a gradual sea level rise during the deposition of these rock units, resulting in replacement of the oxic/dysoxic Sarcheshmeh Formation by the dysoxic/anoxic Sanganeh Formation.
EN
Zooxanthellate corals in the Badenian (Langhian to lower Serravallian) of western Ukraine occur in different lithofacies, but are most abundant in the upper Badenian coralgal reefs of the Ternopil Beds. The coral assemblage consists of five genera, with two predominant (Tarbellastraea and Porites) and three strongly subordinate (Favia, Heliastraea, Siderastrea). The present study is the first record of Heliastraea defrancei in the Fore-Carpathian Basin. The taxonomic composition of the corals indicates that their development occurred in conditions of some ecological stress, most probably connected with climate (location at the northern limit of coral distribution) and sedimentary environment (possible influx of terrigenous material). The coral assemblage shows similarities to numerous fossil reefs of Miocene age from the Paratethyan and Mediterranean realms.
EN
The Stajnia Cave is one of the most important archaeological sites due to the finds of the first remains of Neanderthals in Poland, and several tens of thousands of flint artefacts from the Middle Palaeolithic. Based on geological, geochemical, palaeobotanical, palaeozoological, archaeological and isotope analyses, coupled with absolute age determinations (OSL, U-Th and C14), 15 lithostratigraphic layers were distinguished and palaeoenvironmental conditions during the sedimentation of these beds were determined. The cave loams accumulated through weathering, aeolian and fluvial processes. Their age may be correlated with an interval from the Early Glacial to the Late Pleniglacial of the Visulian (Weichselian) Glaciation. Archaeological relics related to the Neanderthals have been discovered in layer D with an absolute age of about 52,000–45,000 years BP and correlated with MIS 3 – the Middle Plenivistulian (Interplenivistulian). Climate oscillations in the Vistulian are reflected by the type of the sediments and their physical-chemical features, allowing determining warmer interstadial and colder stadial periods. Generally, the climate was cold, characteristic of tundra areas with a typical vegetation and fauna, and with the mean temperature of the warmest month not exceeding 12°C. Based on multi-proxy studies it can be concluded that from layer E1 upwards, the climate conditions became progressively drier. At that time, the climate was cold with continental features enhancing tundra domination. This conclusion is confirmed by palaeontological investigations and the record of stable oxygen isotopes in the teeth of reindeer. The studies have also indicated seasonal migration of reindeer on the tundra that surrounded the cave. Probably, short-term slight climate warmings occurred during the Middle Plenivistulian (Interplenivistulian).
EN
Upper Campanian–Maastrichtian sections on the western flank of the Hun Graben in the Western Sirte Basin (WSB) are displaying two major type facies based on the foraminiferal assemblages. The first one indicates open-marine to outer-shelf conditions, and is represented by numerous bathy-pelagic planktonic foraminiferal species referable to the Radotruncana calcarata, Globotruncana aegyptiaca and the lower part of the Gansserina gansseri Zone (all late Campanian).The second type facies indicates an inner-shelf environment and is represented in the middle-upper part of the Gansserina gansseri Zone (early Maastrichtian) and Racemiguembelina fructicosa (late Maastrichtian) dominated by epi-pelagic planktonic and large benthic foraminifers. Large benthic foraminiferal index species Siderolites calcitrapoides Lamarck and Omphalocyclus macroporus (Lamarck) occur in abundance by the middle–late Maastrichtian. Correlation between planktonic foraminiferal zonation and large benthic foraminiferal zonation is given. An open-marine to outer-shelf environment passed into shallower marine conditions during the late Campanian–early Maastrichtian to late Maastrichtian, then a slight deepening and again shallowing is noticed.
EN
Coal beds could contain various amount of methane. This attribute might be dangerous in shafts or quarrying. Among other things, the works in the coal beds, including drilling, potentially there is a risk of exceeding the methane lower explosive limit. But on the other hand it is a source of unconventional hydrocarbon accumulations. In this paper geochemical characteristic of organic matter of tertiary brown coal from central part of Poland were performed. Geochemical surveys helps to know about genesis of methane from study area. The analysed samples contain various quantity of organic carbon, from 20,74 to 71.93 wt. %. Lignite from examine samples have weak hydrocarbon potential. In tertiary sediments prevails III type of kerogen with admixture of II type of kerogen. The thermal maturity of the tertiary organic matter changes within the interval from 354 to 419 in Tmax scale. Organic matter is immature. The composition of bitumens is different in various part of study area. Elemental analysis confirm that brown coal was comprised mostly by humic-group macerals. Coal samples contain methane with mixed genesis.
EN
Up to now only little attention was dedicated to the study of the trace fossils in the development of the Central Carpathian Paleogene Basin in the Orava region. Occasional trace fossils findings from the Central Carpathian Paleogene formations in the Orava and others regions were referred by Plička (1987). Other specialized works on trace fossils from these formations from the Orava region were not published. Study of trace fossils is strongly influenced by the existence of well exposed outcrops within individual formations. The best exposed outcrops are situated in the basal Borové Formation as well as in the higher parts of Paleogene sequences – mainly in the Zuberec Formation. This preliminary study shows a relatively rich diversity of trace fossils associations across the Central Carpathian Paleogene Basin. We present new finds of trace fossils, within which we have classified 7 ichnogenera, 11 ichnospecies and 2 types of trace fossils, which were not closely systematically classified. Many trace fossils identified in the Orava region are typical for some palaeoenvironments, which are characterized by a specific lithology, nature of the substrate, dynamics of the environment, amount of nutrients and stability or fluctuations of oxygen in the bottom waters. The trace fossils assemblages reflect changes of depositional systems during the tectonic and sequence stratigraphic development of the basin. Early Eocene shallow-sea environment of the Borové Formation including the rocky coast, sandy dynamic littoral, transition - al and internal shelf zones are characterized by findings of traces of Entobia, Gastrochaenolites, Nummipera, Ophiomorpha and Skolithos. On the contrary, a significant deepening of the deposition environment during the Oligocene, documented by turbidite sedimentation of Zuberec and Biely Potok formations is characterised by findings of graphoglyptids ( Spirorhaphe, Nereites, Paleodiction, Protopaleodictyon, Megagrapton ) or traces of deposit feeders ( Arthrophycus, Chondrites, Planolites, Phycodes, Scolicia, Zoophycos).
EN
The paper presents the data on an Eemian–Late Glacial sedimentary sequence from the Zwierzyniec site, central Poland. A number of boreholes document one or two organic layers that occur beneath one or two horizons of clayey and silty deposits of ice-dammed lakes. This study demonstrates to which extent the Zwierzyniec site can contribute to a better understanding of the palaeoenvironmental changes during the Eemian–Vistulian time-frame in central Poland. To study it, a multi-proxy approach was applied, involving: palynological and plant macrofossil analysis, study of rounding of quartz grains and morphology of their surface, and investigations of sand mineralogy and till petrography. The results show that a till bed is overlain by a sandy series corresponding to the glacial-interglacial transition. Either one or two distinct peaks of organic accumulation are evidenced by peat horizons. The lower horizon records spectra with hazel and hornbeam, and did, therefore, accumulate in the Eemian. Observed only in some boreholes, the upper peat horizon marks the Brørup (or the lower part of the Rederstall stadial) represented by forest-steppe conditions with patchy mosaics of larch and further transition into sedges and herbaceous taxa. Localized in between the two peat sequences, the sandy horizon marks a long-lasting aeolian transformation with weathering by frost in the Early Vistulian. Again, significant changes of the palaeoenvironmental regime occurred, and are manifested in the one or two horizons of the glaciolacustrine sediments. This corresponded to the last glaciation in the region, when the ice-dammed lakes formed during the Main Stadial.
EN
Brown coal and overlying sand strata from the Łukowa-4 borehole, located in the northeastern sector of the Carpathian Foredeep in Poland, were studied for palynology. These strata are underlain by Upper Eocene sands, and covered by Middle Miocene rocks. Coal beds yielded infrequent sporomorphs and freshwater algae Botryococcus. The presence of the latter indicates that these deposits accumulated in a freshwater environment whereas sporomorph assemblages point to the presence of mixed forests with a significant portion of thermophilous taxa. Age of the coal beds has been established based both on the presence of species that appear for the last time in the Early Oligocene, and on the similarity with sporomorph spectra from the Lower Oligocene of the Polish Lowlands. Overlying sands yielded marine dinoflagellate cysts, which point to a marine sedimentary setting, and frequent sporomorphs. The latter indicate the presence of mixed mesophytic forests, bush swamps, swamp forests, and riparian forests in the vicinity of lacustrine environments. Stratigraphic analysis of dinoflagellate cyst and sporomorph assemblages suggests that the sands accumulated in early stages of Miocene transgression in the Carpathian Foredeep in the latest Early–early Middle Miocene. Our climatic interpretation of the sporomorph spectra suggests that the climate during deposition of the strata was relatively warm, although less frequent thermophilous taxa recorded in the Miocene sands suggest a slightly cooler climate than that deducted from the spectra yielded by the underlying Lower Oligocene coal beds. Correlation of Lower Oligocene coal beds with neighbouring coeval marine sands suggests diverse morphological conditions in the Carpathian foreland at that time, partly covered by a sea, and partly emerged. A similar, morphologically diverse basement in the Carpathian foreland favoured accumulation of Lower Miocene phytogenic deposits. A similar stratigraphic position of both Lower Oligocene and Lower Miocene coal beds in the Carpathian Foredeep may result in a false correlation of these strata devoid of fossils, which are commonly regarded as Miocene.
EN
A section over 20 m thick of the basal Middle Miocene succession exposed at Lipowiec (Roztocze, SE Poland) was studied for palynology. Thirteen samples were collected from quartz and glauconitic-quartz sands and thin clay layers. Sand samples were barren but clay samples yielded dinoflagellate cysts. Their assemblages consist of reworked Paleogene specimens dominated by the Homotryblium floripes complex (H. floripes and morphologically similar H. plectilum and H. vallum). The presence of reworked Paleogene specimens indicates intense erosion of marine Paleogene strata during initial stages of the Middle Miocene transgression at Roztocze. Analysis of stratigraphical ranges of reworked dinoflagellate cysts and comparison with their occurrences in known epicontinental Paleogene sites of SE Poland suggest an Upper Eocene age of the washed-out strata. The taxonomic composition of the assemblages described suggests that the Upper Eocene deposits accumulated in a near-shore, lagoonal embayment characterized presumably by oligotrophic waters of slightly increased salinity. A high proportion of the Homotryblium floripes complex is also characteristic of reworked assemblages found in younger Miocene strata of neighbouring exposures in Roztocze, which indicates widespread Eocene lagoonal environments in this part of Roztocze. Coeval Eocene strata from the eastern part of Roztocze and from the Carpathian Foredeep show different taxonomic compositions suggesting varied sedimentary settings during Eocene transgression in this region. These differences reflect variable amounts of freshwater influence resulting in a range of environments that ranged from oligotrophic to brackish.
EN
The Badenian section of Anadoly near Kamyanets Podilskyy (Ukrainian Carpathian Foredeep Basin) consists of the Tyras Fm. (gypsum and Ratyn Limestone) and the Ternopil Mb. of the Kosiv Fm. The latter are 5.3 m thick and are composed of dark grey mudstones with limestone intercalations. This study indicates the occurrence of over 54 species of benthic foraminifers and 10 species of planktonics. Benthic foraminifera are represented mainly by calcareous forms; agglutinated tests are very rare. Planktonic foraminifera appear in the upper part of the succession studied. Five benthic foraminiferal assemblages are recognized: A (Elphidium/Lobatula/Astrononion) B (Hauerinidae), C (Cibicidoides/Lobatula), D (Porosononion) and E (Uvigerina/Bulimina). The foraminiferal record indicates deposition in a shallow subtidal environment (20 m depth) of normal marine salinity and temperate waters followed by gradual deepening of the basin to >50 m. Analysis of foraminiferal assemblages indicates that bottom waters were highly oxygenated during deposition of the lower and middle parts of the Anadoly sequence. During deposition of the upper part of the sequence the oxygenation of bottom water gradually decreased, as expressed by a large decrease in the proportion of oxic species and an increase in dysoxic ones. The same set of samples yielded low amounts of palynological organic matter represented by dominant black opaque phytoclasts; bisaccate pollen grains and dinoflagellate cysts are rare. Taxonomically impoverished assemblages of the latter consist of dominant Polysphaeridium and Cleistosphaeridium placacanthum associated with Lingulodinium machaerophorum and a few other taxa. The taxonomically richest assemblage was found in the topmost sample. These changes were interpreted as indicative for increased salinity in the surface water layer, with its maximum in the middle part of the section; the assemblage from the topmost part is characteristic for normal marine salinity.
EN
The aim of this study was the qualitative and quantitative analysis of the calcareous nannofossil assemblages of the Machów Formation, belonging to the supra-evaporitic complex of the Polish Carpathian Foredeep Basin (PCFB). The work was concentrated in the eastern part of the PCFB, in the Sieniawa–Rudka area (Ryszkowa Wola Horst). Samples were collected from the Rudka-13 and Wylewa-1 boreholes. On the basis of calcareous nannoplankton, these deposits were assigned to the upper part of the NN6 Zone combined with the NN7 Zone, which corresponds to the Sarmatian s.s. of the Central Paratethys (upper Serravallian of the Mediterranean scale). Conclusive determination of the biozone NN7 was problematic, owing to the absence of the rare zonal marker species Discoaster kugleri. The typical association of the undivided NN6–NN7 Zone was of low species diversity and usually dominated by Coccolithus pelagicus, Cyclicargolithus floridanus and Reticulofenestra pseudoumbilica (> 7 µm). On the basis of the relative abundance of species, a significant amount of redeposition was deduced. The reworked nannofossils were mostly Eocene in age. The Oligocene, Early Miocene and Late Cretaceous species occurred much less frequently. The dominance of Eocene forms indicates the Carpathians as the main supply area. The Late Cretaceous taxa may have originated from the Senonian marly deposits of the Miechów Trough in the north. Statistical treatment of the quantitative data was performed using multivariate cluster analysis and Nonmetrical Multidimensional Scaling (nMDS). The composition of the calcareous nannofossil assemblages, together with the high percentage of allochthonous taxa, indicate a shallow, coastal environment with a high supply of nutrients.
EN
The post-evaporitic upper Badenian (Middle Miocene) succession of the Roztocze (marginal zone of the Carpathian Foredeep Basin) consists of shallow-marine sands and organodetrital deposits. The latter, although predominantly coarse-grained, include very rare and usually very thin intercalations of fine-grained, loamy material. A few such clay layers were sampled for their palynological content in quarries at Józefów (Józefów and Pardysówka) and Żelebsko. The clay samples yielded palynological organic matter, in contrast to organodetrital limestone samples, which were barren. The palynofacies composition, both presence/absence of land-derived material and the specific composition of aquatic material, are useful for the palaeoenvironmental reconstructions of sedimentary settings. During late Badenian time, the sedimentary setting of the deposits studied was characteri- zed by proximity to the shoreline, which, however, supplied limited input of terrestrial matter, and by restricted marine conditions caused by increased salinity. During the latest Badenian, water salinity presumably underwent a further increase, leading to the collapse of the dinoflagellate floras. The frequent occurrence of reworked Palaeogene dinoflagellate cysts in upper Badenian samples and their absence from the uppermost Badenian indicate variable intensity of erosion of the epicontinental Palaeogene strata during the Middle Miocene at Roztocze.
EN
Two dinosaur footprints: Eubrontes cf. giganteus and Grallator tenuis, both attributed to theropods, have been found in the Lower Jurassic Thaiat Member of the Lathi Formation at the Thaiat ridge, near Jaisalmer in western Rajasthan, India. The footprints were left in sediments of a tidal origin, located in profile a few meters above a marked transgressive/flooding surface. They show different states of preservation – the smaller Grallator tenuis represents a well-preserved concave epirelief footprint on the upper surface of a sandstone containing nerineid gastropod shells, while the bigger Eubrontes cf. giganteus footprint shows a rare state of preservation as a positive epirelief on the top of a calcareous sandstone bed, where recent erosion exposed the footprint cast by removing the mud above and around the footprint. The Thaiat ridge section has been amended in its lower part, to indicate the marked transgressive surface. Geochemical analyses and calculated weathering indices (such as CIA) show that the hinterland climate was seasonal to semi-arid during deposition of that part of the succession.
EN
The quality of palaeoenvironmental reconstructions based on macrofossil carbonate critically depends on preservation of the shell material because post-depositional processes can modify its structural, chemical and isotopic composition, potentially overprinting or completely erasing palaeoenvironmental information. A suite of methods can be employed to evaluate the impact of diagenetic processes on the primary geochemical signatures of samples. Here we review the benefits and shortcomings of the most commonly employed optical (optical microscopy, cathodoluminescence microscopy, scanning electron microscopy) and chemical (trace element abundances, isotopic ratios) screening techniques used to assess the alteration degree of low-Mg calcite macrofossils and summarize the findings on diagenetic trends observed for elemental and isotopic systems in such materials. For a robust evaluation of the preservation state of biogenic calcite, it is advisable to combine a set of complementary techniques. Absolute limiting values of element and isotope ratios for discarding diagenetically altered materials cannot be universally applied, but should rather be evaluated on a case to case basis. The evaluation can be improved by analyses of diagenetic carbonate and altered fossil materials, which help constraining the diagenetic trajectories in the sampled specimens. Quantification of post-depositional alteration is possible, but in most cases the complexity of diagenetic systems hampers the possibility of retrieving original proxy values for palaeoenvironmental reconstructions from partially altered materials.
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