Macerals in sediments

The study of particulate organic matter (OM) in Arctic Ocean sediments from the Late Cretaceous to the Eocene (IODP Expedition 302) has revealed detailed information about the aquatic/marine OM fluxes, biological sources, preservation and export of terrestrial material. Here, we present detailed data from maceral analysis, vitrinite reflectance measurements and organic geochemistry. During the Campanian/Paleocene, fluxes of land-derived OM are indicated by reworked and oxidized macerals (vitrinite, inertinite) and terrigenous liptinite (cutinite, sporinite). In the Early Eocene, drastic environmental changes are indicated by peaks in aquatic OM (up to 40-45%, lamalginite, telalginite, liptodetrinite, dinoflagellate cysts) and amorphous OM (up to 50% bituminite). These events of increased aquatic OM flux, similar to conditions favoring black shale deposition, correlate with the global d13C events "Paleocene/Eocene Thermal Maximum" (PETM) and "Elmo-event". Freshwater discharge and proximity of the source area are documented by freshwater algae material (Pediastrum, Botryococcus) and immature land-plant material (corphuminite, textinite). We consider that erosion of coal-bearing sediments during transgression time lead to humic acids release as a source for bituminite deposited in the Early Eocene black shales.

(Table 2) Age determination of sediments from lake basins near Polyarny, Russia

A relative sea-level curve for the Holocene is constructed for Polyarny on the Kola Peninsula, northwest Russia. The curve is based on 18 radiocarbon dates of isolation contacts, identified from lithological and diatomological criteria, in nine lake basins situated between 12 and 57 m a.s.l. Most of the lakes show a conformable, regressive I-II-III (marine-transitional-freshwater) facies succession, indicating a postglacial history comprising an early (10,000-9000 radiocarbon years BP) phase of rapid, glacio-isostatically induced emergence (~5 cm/year) and a later phase (after 7000 years BP,) having a moderate rate of emergence (<0.5 cm/year). Three lakes together record a phase of very low rate of emergence or slight sea-level rise at a level of ~27 m a.s.l., between 8500 and 7000 years BP, which correlates with the regional Tapes transgression. Pollen stratigraphy in the highest lake shows that the area was deglaciated before the Younger Dryas and that previously reconstructed Younger Dryas glacier margins along the north Kola coast lie too far north

X-ray fluorescence scannings, diatoms, and dinocyst of ODP Site 189-1172

Eocene sediments drilled at the East Tasman Plateau (ETP) exhibit well-defined cycles, high-resolution magnetic stratigraphy, and environmentally-controlled dinoflagellate and diatom distribution patterns. We derive a cyclostratigraphy from the spectral analysis of high-resolution elemental concentration records (Ca, Fe) for this shallow marine time series spanning the middle to early late Eocene (C16n.2n - C21). Changes in carbonate content, the ratio between Gonyaulacoid and Peridinioid dinocysts, and relative abundance of "oligotrophic" diatoms serve as proxies for a high-resolution climatic and sea-level history with high values representing high sea-level stands and decreased eutrophy of surface waters. Changing ratios between high latitude dinocysts versus cosmopolitan species provide clues on sea surface temperature trends and water mass exchange. Our results show that the relatively shallow-water middle Eocene environments of the ETP are influenced by orbitally-forced climatic cycles superimposed on third order relative sea-level changes. Changes in the dominance of Milankovitch frequency at ~38.6 Ma (late Eocene) is related to an initial deepening-step within the Tasmanian Gateway prior to the major deepening during the middle late Eocene (~35.5 Ma). Decreasing sedimentation rates at 38 Ma and 37.2 Ma reflect winnowing associated with sea-level fall. This episode is followed by renewed transgression. Dinocyst distribution patterns indicate high latitude, probably cool temperate surface water conditions throughout, with the exception of a sudden surge in cosmopolitan species near the base of subchron C18.2r, at ~41 Ma; this event is tentatively correlated to the Middle Eocene Climatic Optimum.

(Table A1) Calcium carbonate content of boreholes Kirchrode I and II

The technical details of drilling and coring at the Kirchrode I and II sites are presented. At these sites, a sequence of claystones and marlstones from an Albian shelf basin was recovered. Constraints on the ages of the sediments in the two boreholes are provided by the occurrence of the inoceramid bivalve Actinoceramus sulcatus, the first appearance of which is used to define the Middle/Upper Albian boundary and by observed facies changes that can be correlated to the established lithostratigraphy. The cores from the two boreholes provide a rather complete, 285-m-long sequence of the Upper Albian, with a 155.5-m-long overlap. Analysis of the tectonic structures showed considerable shortening in the Middle and Lower Albian part of the sequence due to normal faulting. Of the Upper Albian, only the lowermost part is affected by faults. The increase in sedimentation rates of terrigenous detritus and of marine biogenic carbonate, which occurs in the basal part of the C. auritus Subzone, is interpreted to reflect a regional change to a more humid climate and regional tectonic movements (uplift of the Rhenish Bohemian massif, subsidence of the Lower Saxony basin intensified locally by halokinetic movements). The further increase in marine productivity in the latest Albian may be related to upwelling of more nutrient-rich deep water along submarine relief in this shelf sea. Identification of Milankovitch cyclicity documented by the fluctuating CaCO3 contents of the sediments is used (i) to constrain the minimum time represented by the Upper Albian deposits, and (ii) to determine the duration of the sea level cycles (Cycle V: >=1.6 Ma, Cycle VI: >=2 Ma), and (iii) to establish the duration of the Late Albian ammonite subzones (e.g. Callihoplites auritus Subzone: 2.1 Ma). Average sedimentation rates determined from the identified 100-ka eccentricity cycles show a stepwise increase in sedimentation rates from 1-2 cm/1000 a in the Lower Albian dark claystones to 7-13 cm/1000 a in the late Late Albian. In addition to the general deepening trend through the Late Albian, two, nearly completely documented 3rd-order sea-level cycles in the Upper Albian of Kirchrode I were recognised, plus another one, cut short by faulting, at the base of the Upper Albian (documented in Kirchrode II). These global sea-level cycles were identified on the basis (a) of the sequence of the abundance maxima of selected benthos and plankton groups, (b) of trends in the fluctuations of the CaCO3 content, and (c) of the abundance of glauconite. The transgression periods in this Upper Albian deep shelf-basin are characterised by intensified circulation. This intensified circulation is found to have affected first the surface-near waters, resulting e.g. in an increase in the abundance of immigrant plankton and nekton species from the Tethys. At a later stage the deep water was affected, supporting then an increased population of suspension-feeding benthos, and causing condensation and erosion in the sediment at the sea floor.

Location and ages of terrestrial peatlands located on continental shelves and in coastal sediments

This synthesis dataset contains records of freshwater peat and lake sediments from continental shelves and coastal areas. Information included is site location (when available), thickness and description of terrestrial sediments as well as underlying and overlying sediments, dates (when available), and references.

Geochemical parameters of sediments and waters in areas of ocean barrier zones

Geochemical barrier zones play an important role in determining various physical systems and characteristics of oceans, e.g. hydrodynamics, salinity, temperature and light. In the book each of more than 30 barrier zones are illustrated and defined by physical, chemical and biological parameters. Among the topics discussed are processes of inflow, transformation and precipitation of the sedimentary layer of the open oceans and more restricted areas such as the Baltic, Black and Mediterranean Seas.

Palaeoenvironment records of six sediment cores collected in the Gulf of Carpentaria

The Gulf of Carpentaria is an epicontinental sea (maximum depth 70 m) between Australia and New Guinea, bordered to the east by Torres Strait (currently 12 m deep) and to the west by the Arafura Sill (53 m below present sea level). Throughout the Quaternary, during times of low sea-level, the Gulf was separated from the open waters of the Indian and Pacific Oceans, forming Lake Carpentaria, an isolation basin, perched above contemporaneous sea-level with outlet channels to the Arafura Sea. A preliminary interpretation is presented of the palaeoenvironments recorded in six sediment cores collected by the IMAGES program in the Gulf of Carpentaria. The longest core (approx. 15 m) spans the past 130 ka and includes a record of sea-level/lake-level changes, with particular complexity between 80 and 40 ka when sea-level repeatedly breached and withdrew from Gulf/Lake Carpentaria. Evidence from biotic remains (foraminifers, ostracods, pollen), sedimentology and geochemistry clearly identifies a final marine transgression at about 9.7 ka (radiocarbon years). Before this transgression, Lake Carpentaria was surrounded by grassland, was near full, and may have had a surface area approaching 600 km-300 km and a depth of about 15 m. The earlier rise in sea-level which accompanied the Marine Isotopic Stage 6/5 transgression at about 130 ka is constrained by sedimentological and biotic evidence and dated by optical- and thermoluminescence and amino acid racemisation methods.

Temperatures, salinity, wind speed, grain sizes and foraminifera abundance in the Great Belt Channel, western Baltic Sea

The Great Belt, the largest inlet to the Baltic Sea, has a deep and well defined channel system. A distinct thermohaline layer at roughly 18 to 20 m of water depth separates the saltier and generally cooler deeper North Sea water from the brackish and warmer surface water. It is practically a current dominated area, with the strongest bottom currents due to prolonged west winds. The size and shape of the surface sediments and their grain size distributions show a close relationship with the prevailing hydrographical conditions. Southerly current marks predominate while northerly directions are confined to 10 to 14 m of water depth. The degree of bioturbation is highest in the uppermost sedimentary cover where practically all original stratification has been destroyed. Various bioturbate structures have been identified with the fauna. Coiling ratios of Ammonia beccarii (Linnaeus) have been successfully applied for correlation in the postglacial sediments of the early Littorina Transgression. The succession shows that in the Boreal brackish water conditions were probably followed by peat and limnic sediments as the sea regressed. With the Littorina Transgression, the sea again entered the area and high sedimentation rates resulted in the major deposits of the Great Belt. At least for the last 4000 years, sedimentation rates had been very low. Present day currents sweep out the sediments, mainly to the southern marginal areas.

Distribution of microorganisms in recent sediments of Kiel Bay

Die angewandte Mikropaläontologie bestimmt heute im wesentlichen das Alter eines Gesteins mit Hilfe von Faunenvergesellschaftungen. Aus der Zusammensetzung der Fauna, aus dem Einsatz oder Fehlen bestimmter Gattungen und Arten, aus den Mineralien, die das Gestein aufbauen, aus dem ganzen Bild, das eine aus einem Gestein herausgeschlämmte Fauna dem Bearbeiter gibt, läßt sich das Alter dieses Gesteins festlegen. Will man aber verschiedene Bohrungen, vor allem auch räumlich weit voneinander getrennter Gebiete, miteinander parallelisieren, so liegt das Kernproblem der Mikropaläontologie in der Frage, ob es sich bei verschiedenen Faunen tatsächlich um Alters- oder nur um Faziesunterschiede handelt. Da die Grundlagen der mikropaläontologischen Arbeitsweise zum weitaus größten Teil auf den Ergebnissen von Untersuchungen fossiler Faunen beruhen, müssen zu ihrer Unterbauung Untersuchungen an recentem Material folgen. Besonders spielt das Ineinandergreifen mariner und brackischer Sedimente in der angewandten Mikropaläontologie eine große Rolle. Auf Grund der Tatsache, daß ein großer Teil von Gattungen und Arten der Foraminiferen an der Wende Kreide/Tertiär ausstirbt und neue an ihre Stelle treten, stellt Glässner (1948) die Behauptung auf, daß die aktualistisch gewonnenen Ergebnisse für vortertiäre Faunen nur eine geringe Bedeutung besitzen. Auch seien vortertiäre, brackische Foraminiferen nicht bekannt (Glässner 1948, S. 191). Hiltermann (1948) konnte aber bereits im nordwestdeutschen Malm brackische, d. h. in Brackwasser eindringende Foraminiferen nachweisen. Auf jeden Fall behalten aktualistische Unterlagen ihren Wert für das Tertiär und Quartär. Die Faunen, die in recenten, brackischen Sedimenten nebeneinander auftreten, sind in einem Bohrprofil in einem Gestein übereinander zu erwarten. Gelingt es, die Beziehungen einer recenten Fauna zu ihrer Umwelt zu klären, dann können umgekehrt aus fossilen, ihnen gleichen oder ähnlichen Faunen Rückschlüsse auf die Entstehungsbedingungen von Gesteinen gezogen werden. Unter Umständen können der Verlauf einer Transgression, Küstennähe, die Höhe des Salzgehaltes des Meerwassers, die vorherrschenden Temperaturen u. a., aus ihnen abgelesen werden. Die Ostsee ist ein klassisches Brackwassergebiet der Erde. Ihr westlicher Teil, die Kieler Bucht, wurde erst in jüngster geologischer Zeit vom Meer überflutet. Nach Tapfer (1940) begann hier die flandrische Transgression erst etwa um 7500 v. d. Zw. mit dem Erreichen des heutigen Meeresniveaus. Seit dieser Zeit erst entstehen neue Küstenformen, wird der Meeresboden umgelagert und bilden sich marine und brackische Absätze in diesem Gebiet.

Sedimentology of a profile from Etoliko Lagoon, Western Greece

A key feature of Greece is the large amount of historical and archaeological records. The sedimentary record of the Etoliko Lagoon, Aetolia, Western Greece, offers an ideal opportunity to study human-environment interaction and to disentangle natural and anthropogenic imprints in the sedimentary record. By applying an interdisciplinary approach of combining geoscientific methods (XRF, LOI, grain size analysis) with archaeological and historical records, the 8.8 m long sedimentary sequence ETO1C reveals the palaeoenvironmental history of the lagoon and its catchment since 11,670 cal BP. With a thorough chronology based on 14C age-depth-modelling including varve counting, different evolutionary stages were put in a chronological context. These stages include a lake period (11,670-8310 cal BP) followed by a period of sporadic saltwater intrusion (8310-1350 cal BP) as a result of continuing transgression. Phases of limnic predominance associated with freshwater inflow of episodically activated distributaries (around 5230 cal BP) still occurred. By 1350 cal BP, ongoing sea level rise had connected the lagoons of Etoliko and Messolonghi and freshwater influence had ceased. With the onset of settlement activity in the Late Helladic (1700-1100 cal BC) humans took advantage of the prevailing environmental landscape. A sudden increase in coarse sedimentation correlates with the history of human occupation with its peak of prosperity from the Late Helladic until the end of the Hellenistic Period (30 cal BC).

Carbon and oxygen isotope ratios of Selinde River, southeastern Siberian platform

Carbon isotopic data from the Selinde section in the southeastern part of the Siberian platform area are correlated with the reference isotopic profile from the Lower Cambrian stratotype sections of the Lena Aldan region, but also show additional d13C excursions unrecognized there. The chemostratigraphic correlation suggests that the geological and fossil record of the lower Pestrotsvet Formation in the Selinde section has a deeper history than the stratotype region. This conclusion is important for both constraining the age of the earliest Cambrian marine transgression on the Siberian platform and providing a clearer understanding of the pace and order of early Cambrian geochemical and biological events.

Age determination of sediment cores from the Laptev Sea

To establish a chronology of the Holocene transgression in Arctic Siberia, a total of 14 sediment cores from the Laptev Sea continental slope and shelf were studied covering the water depth range between 983 and 21 m. The age models of the cores were derived from 119 radiocarbon datings, which were all analyzed on marine biogenic calcite (mainly bivalve shells). The oldest shell sample was found at the slope and dates back to about 15.3 cal. ka, indicating that the time interval investigated starts prior to the onset of the meltwater pulse 1A (~14.2 cal. ka) when global sea-level rose dramatically. The inundation history was reconstructed mainly on the basis of major changes in average sedimentation rates (ASR), but also other sedimentological parameters were incorporated. A diachronous reduction in ASR from the outer to the inner shelf region is recognized, which was related to the southward migration of the coastline as the primary sediment source. We estimate that the flooding of the 50-, 43-, and 31-m isobaths was completed by approximately 11.1, 9.8, and 8.9 cal. ka, and that Holocene sea-level highstand was approached near 5 cal. ka. Between these time intervals, sea level in the Laptev Sea rose by 5.4, 13.3, and 7.9 mm/year, respectively.

(Table 1) Luminescence datings from Varchushka and Pyoza rivers, Russia

The Pyoza River area in the Arkhangelsk district exposes sedimentary sequences suitable for study of the interaction between consecutive Valdaian ice sheets in Northern Russia. Lithostratigraphic investigations combined with luminescence dating have revealed new evidence on the Late Pleistocene history of the area. Overlying glacigenic deposits of the Moscowian (Saalian) glaciation marine deposits previously confined to three separate transgression phases have all been connected to the Mikulinian (Eemian) interglacial. Early Valdaian (E. Weichselian) proglacial, lacustrine and fluvial deposits indicate glaciation to the east or north and consequently glacier damming and meltwater run-off in the Pyoza area around 90-110 ka BP. Interstadial conditions with forest-steppe tundra vegetation and lacustrine and fluvial deposition prevailed at the end of the Early Valdaian around 75-95 ka BP. A terrestrial-based glaciation from easterly uplands reached the Pyoza area at the Early to Middle Valdaian transition around 65-75 ka BP and deposited glaciofluvial strata and subglacial till (Yolkino Till). During deglaciation, laterally extensive glaciolacustrine sediments were deposited in ice-dammed lakes in the early Middle Valdaian around 55-75 ka BP. The Barents-Kara Sea ice sheet deposited the Viryuga Till on the lower Pyoza from northerly directions. The ice sheet formed the Pyoza marginal moraines, which can be correlated with the Markhida moraines further east, and proglacial lacustrine deposition persisted in the area during the first part of the Middle Valdaian. Glacio-isostatic uplift caused erosion followed by pedogenesis and the formation of a deflation horizon in the Middle Valdaian. Widely dispersed periglacial river plains were formed during the Late Valdaian around 10-20 ka BP. Thus, the evidence of a terrestrial-based ice sheet from easterly uplands in the Pyoza area suggests that local piedmont glaciers situated in highlands such as the Timan Ridge or the Urals could have developed into larger, regionally confined ice sheets. Two phases of ice damming and development of proglacial lakes occurred during the Early and Middle Valdaian. The region did not experience glaciation during the Late Valdaian.

Tab. I: Alkenon analyses on sample material of cores Krummland KR-1 und Dagebüll DA-1

Geochemical studies of organic "biomarker" compounds were applied to Eemian sediments cored at Dagebuell (DA-1) on the west coast, and at Krummland (KR-1) in the east of the Baltic Zone of Schleswig-Holstein, Germany. 10 samples from the early stage of the Eemian Transgression to the high Eem at Krummland, and 24 samples from the peak and late phases of the Eemian at Dagebuell provide new insights on the development of the Eemian Sea in the region. C37-C39-ethyl- and methyl-ketones in the Krummland sediments indicated unstable conditions at the onset of the marine trangression, and freshwater influence in keeping with their shallow nearshore environment. In the Dagebuell deposits, patterns typical of marine to brackish conditions were observed, comparable to those found today in the Skagerrak and Belt Sea areas. The sea-surface temperatures estimated from the alkenone unsaturation ratio UK37 at DA-1 corroborate the evidence from "standard" faunal and pollen assemblages, and lithological successions. Here, the temperature maximum attained in pollen assemblage zone PAZ Illc, indicates the early onset of very warm conditions, preceding the highest sea level of the penultimate interglacial by 8,000 years, based on previously published U/Th ages.