نتایج جستجو برای: diagenesis

تعداد نتایج: 1443  

Journal: :American journal of physical anthropology 2012
Emma Loftus Judith Sealy

Stable isotope analysis of skeletal tissues is widely used in archeology and paleoanthropology to reconstruct diet. In material that is poorly preserved or very old, the tissue of choice is frequently tooth enamel, since this is less susceptible to diagenesis. The relationships between carbon isotope ratios in tooth enamel (δ(13) C(enamel) ), bone collagen (δ(13) C(collagen) ), and bone apatite...

Journal: :Computers & Geosciences 2004
S. Katsev D. G. Rancourt I. L'Heureux

Mathematical modeling of sediment early diagenesis always involves choosing and describing a set of chemical reactions and processes that is both self-consistent and sufficient for the problem at hand. This critical choice is always a compromise between describing the system’s complexity in all details and using a manageable set of reactions with known or obtainable parameters such as equilibri...

Journal: :Journal of human evolution 2005
Matt Sponheimer Darryl de Ruiter Julia Lee-Thorp Andreas Späth

A previous study of strontium/calcium (Sr/Ca) ratios in Paranthropus suggested that it consumed more animal foods than was previously believed. However, that study looked at Sr/Ca in fossil bone, which is known to be highly susceptible to diagenesis. Enamel, in contrast, is resistant to post-mortem alteration making it a more appropriate material for Sr/Ca analysis of Plio-Pleistocene fossils. ...

2010
K. J. Mohamed D. Rey B. Rubio M. J. Dekkers F. Vilas

Early diagenetic modification of magnetic properties is an important process in marine sediments, but temporal and spatial variability of diagenetic processes have rarely been reported for recent coastal sediments. The magnetic properties of sediments from the Ria de Vigo (NW Spain) define a marked three-part zonation with depth. The uppermost zone is magnetically dominated by (titano-)magnetit...

1999
Panagiotis Karkanas Ofer Bar-Yosef Steve Weiner

Prehistoric cave sediments are often subjected to severe mechanical and chemical alteration, making it difficult to interpret aspects of their archaeology. Theopetra cave offers unique opportunities to resolve aspects of this problem, particularly in relation to chemical changes, because it has a relatively well defined stratigraphy and its older deposits have been subjected to unusually severe...

Journal: :Journal of environmental monitoring : JEM 2009
Damien A Devault Sébastien Delmotte Georges Merlina Puy Lim Magali Gerino Eric Pinelli

The in situ effect of biological activity on herbicide degradation was studied in sediment. Early diagenesis indicators of organic matter (OM) was selected to provide information on the presence and the kinetics of the various biotic and abiotic processes involved in the degradation of fresh organic matter, the vector of herbicides in sediment. Two tandem-coring samples were taken in the Malaus...

Journal: :Water 2022

Diagenesis includes all the biological, physical, chemical, biochemical, and physicochemical alterations that occur immediately after deposition prior to low-grade metamorphism [...]

2015
Jena E. Johnson Samuel M. Webb Chi Ma Woodward W. Fischer

Oxidation of manganese (II) to manganese (III,IV) demands oxidants with very high redox potentials; consequently, manganese oxides are both excellent proxies for molecular oxygen and highly favorable electron acceptors when oxygen is absent. The first of these features results in manganese-enriched sedimentary rocks (manganese deposits, commonly Mn ore deposits), which generally correspond to t...

Journal: :Frontiers in Earth Science 2022

Hydrothermal-reactor experiments were conducted to investigate the potential formation of chlorite and microquartz grain coatings on detrital quartz feldspar grains, understand their role in inhibiting (albite) overgrowths. Modern-day proximal distal unconsolidated sediment from Bute Inlet (British Columbia, Canada) with known amounts precursor clay content, used as starting material. The sampl...

Journal: :IOP Conference Series: Earth and Environmental Science 2019

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