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Showing 1 to 20 of 23 for “"microfossil"”.
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Stratigraphic and microfossil evidence of repeated late Holocene tsunami inundation at Sitkalidak Island, Alaska
… ruptures, we present stratigraphic and microfossil evidence of repeated tsunami inundation over the last ~400 years at Sitkalidak Island, located 0.5 km off the coast of south-central Kodiak Island. Peat cores collected from an estuary in southern Sitkalidak Island reveal three …
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Foraminiferal species distributions and sedimentological dynamics of the Knysna Estuary, South Africa
… substantial deterioration. Investigating the microfossil assemblages in the Knysna Estuary is imperative, since foraminifera serve as essential ecological indicators, and can be used to monitor the health of the ecosystem during development, as they are extremely sensitive to any environmental …
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The Microbiostratigraphy of the Paiaeocene of the Northwest European Continental Shelf
… King, 1989, and the so-called "bioevents" (i.e. microfossil marker horizons) described by Mudge & Copestake, 1992. The emphasis of the study was placed on the stratigraphical distribution of the microfaunas, particularly in the offshore realm where the majority of the boreholes (7) are located in …
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Hazard Identification and Coastal Stratigraphy in Crescent Harbor, Northeast Whidbey Island, Washington
… cal. yrs. BP. The lithostratigraphy and diatom microfossil assemblages reveal a marsh peat abruptly overlain by intertidal mud, indicating rapid subsidence. Analysis of the modern-day position of depositional facies indicates subsidence from a high marsh to a tidal-flat environment representing …
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Quantifying coseismic land-level change along the Cascadia subduction zone in central Oregon
… land elevation. Transfer functions (TFs) using microfossil assemblages (e.g., diatoms, foraminifera) from these layers allow for precise reconstructions of coseismic subsidence. The two studies in this dissertation employ a new diatom-based transfer function for quantifying coseismic subsidence, …
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Aspects of the Flandrian vegetational history of south-west Scotland, with special reference to possible Mesolithic impact
… Loch Doon and Loch Dee to enable comparison of microfossil stratigraphies. At Loch Doon several cores were analysed across the rise in Alnus. Preliminary counts were made from a core from Loch Doon itself. Radiocarbon dating gave additional confidence to the chronological framework. The …
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Exploring the silicification of microbes and understanding their role in the fossil record
… minerals. These results are consistent with microfossil assemblages found in early diagenetic chert deposits throughout the Proterozoic. The data suggest abundant Ca-rich sulfated polysaccharides in the exopolymeric substance (EPS), which are likely the site of silicification. Interactions …
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Sedimentological analyses of late Pleistocene sediments from Lake Lisan in the Jordan River Valley, Israel
… smear slide analysis, sieve residue analysis and microfossil count data were used to interpret the depositional setting in which the sediments were produced. The fine-grained and homogenous characteristics of the sediments and their location at -214 m asl. suggest that the deposits were formed in …
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The role of biological production in pleistocene atmospheric carbon dioxide variations and the nitrogen isotope dynamics of the southern ocean
… utilization in the Antarctic. A study of diatom microfossil-bound N in sediments suggests that this N is native to the diatoms, that it is invulnerable to early diagenesis, and that its isotopic compositon varies with that of the sinking flux. Paleoceanographic records of diatom-bound N isotopic …
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Infusion cuisine: a study of the value of foods in a pottery context across the transition to agriculture in the southern Baltic
… surface deposits were combined with novel plant microfossil investigations of starches from the surface ‘foodcrusts’, and stylistic information on the pots. An automated programme was developed to assign starches to a taxonomic class, based on comparison to modern reference examples according to …
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The response of wetlands to sea level rise: Ecologic, paleoecologic, and taphonomic models
… that the traditional approach of using a single microfossil group to interpret sea-level trends may be inadequate. The combined thanatocoenosis approach can produce better controls on paleoecologic and paleoclimatic interpretations, and will allow for better predictions of future trends.
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Use of carbon isotope and C/N geochemistry in reconstructing vegetation communities: a mid- to late- Holocene palaeoenvironmental investigation from Romney Marsh, Kent, UK
… saltmarsh communities, identified by pollen and microfossil remains, have been tested for ς¹³C and C/N. There is eveidence for post-depositional changes in the alder carr communities, with a negative shift of between 0.7%₀ and 2%₀ from the contemporary soil to fossil peat. Three periods of …
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Antarctic phytoplankton and climate change using Holocene sedimentary DNA, fossils and chemical proxies.
… satellite records span only recent decades, and microfossil archives under-represent non-siliceous, non-fossilising taxa. High-resolution archives are needed to place recent changes within the last 1–1.5 millennia, to understand if modern changes are unprecedented, and how these climatic changes …
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The rise of modern mammalian faunas: tempo and mode of faunal turnover in western Montana during the Oligocene
… that many of the well sampled vertebrate microfossil assemblages from the beds can be considered isotaphonomic for the purpose of comparing biodiversity through time. Geometric morphometric analyses of the upper third molars and lower fourth premolars of entoptychine gophers, a very …
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New Zealand late miocene biostratigraphy and biochronology: Studies of planktic foraminifers and bolboforms at oceanic sites 593 and 1123, and selected onland sections
… from local data. The study also links the major microfossil bioevents established in the offshore records at Sites 593 and 1123 back into selected onland New Zealand sections (730 samples), where the late Miocene is rather poorly resolved, thereby improving our ability to date, correlate, and …
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The petrography and major element geochemistry of the phosphorite nodule deposits on the Agulhas Bank, South Africa
… The latter classes comprise (i) phosphatized microfossiliferous limestones (N I class); (ii) phosphatized highly ferruginous microfossiliferous limestones (N II class); and (iii) nodules composed of a poorly sorted mixture of quartz, glauconite and microfossil grains set in a …
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The late holocene evolution of coastal wetlands in Argyll, Western Scotland
… have reached full equilibrium with sea-level. Microfossil analysis of the Loch Etive core helps to identify a more complex depositional history with an underlying trend of marine transgression for the ca. 110 year period of marsh development recorded in these sediments. Over the most recent …
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Micropalaeontology, Palaeoenvironments and Sequence Stratigraphy of the Sulaiy Formation of Eastern Saudi Arabia
… the two formations using foraminifera and other microfossil assemblages. In the eastern side of Saudi Arabia, the Sulaiy Formation and the base of Yamama Formation are poorly studied. The main objectives of this study is to enhance the understanding of the Sulaiy Formation sequence …
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Earthquakes and sea-level change in Hokkaido, north-east Japan
… on regional deformation patterns, and apply microfossil-based techniques to multiple earthquake cycles at sites to help define the spatial extent of land motions associated with different events.
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