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Full-Text Articles in Geology
Stable Isotope Studies Of Paleoenvironment And Paleoclimate From Afar, Ethiopia, Zelalem K. Bedaso
Stable Isotope Studies Of Paleoenvironment And Paleoclimate From Afar, Ethiopia, Zelalem K. Bedaso
Zelalem Bedaso
ABSTRACT The sedimentary deposits of the Hadar Formation at Dikika and the Mount Galili Formation at Galili preserve a wealth of paleoenvironmental and paleoclimatic records spanning the last 5.29 Ma. Stable carbon and oxygen isotopic compositions of herbivore tooth enamel were analyzed for more than 600 specimens of 15 different taxa from 10 stratigraphic intervals. The application of carbon and oxygen isotopes here aims principally at reconstructing shifts in the relative abundance of C4 grasses, and its implications for climate indicators including temperature, aridity, and seasonality. The full range of δ13Cenamel values throughout the Plio-Pleistocene signifies a wide range of …
Clay Fabric And Mass Physical Properties Of Surficial Marine Sediment Near The Deepwater Horizon Oil Spill, Andrew Head, Richard H. Bennett, Jessica R. Douglas, Kenneth J. Curry
Clay Fabric And Mass Physical Properties Of Surficial Marine Sediment Near The Deepwater Horizon Oil Spill, Andrew Head, Richard H. Bennett, Jessica R. Douglas, Kenneth J. Curry
Kenneth J. Curry
Surficial sediment was obtained on the RV Cape Hatteras Cruise (2010) from the seafloor at a water depth of 1570 meters located at latitude 28°44'20.16"N and longitude 88°20'24.96"W in close proximity to the Deepwater Horizon well, Gulf of Mexico. Preliminary clay nano- and microfabric observation using a transmission electron microscope (TEM) depicted a sediment rich in clays and organic matter (OM) especially in the upper 2 cm subbottom. Initial analysis of TEM micrographs depicted a high porosity clay sediment. Initial study of the mass physical properties revealed water content ωt = 67.32 – 67.28% (percent total mass), porosity n= 84.1 …
Hierarchical Modeling: Biogeochemical Processes And Mechanisms That Drives Clay Nano- And Microfabric Development, Kenneth J. Curry, Richard H. Bennett, Paula J. Smithka, Matthew H. Hulbert
Hierarchical Modeling: Biogeochemical Processes And Mechanisms That Drives Clay Nano- And Microfabric Development, Kenneth J. Curry, Richard H. Bennett, Paula J. Smithka, Matthew H. Hulbert
Kenneth J. Curry
Conceptual scientific models of clay and clay fabric development can be constructed profitably by considering chemical and physical systems in terms of an ordered hierarchy. We develop here a hierarchical model of early stages of marine sediment development identifying processes and focusing on mechanisms. While the focus of our model is on mechanisms, the physical aspects of the hierarchy are cast in terms of the scale of structure in which the mechanisms occur. Our primary scale of interest is the nanometer (nanofabric) level of organization of sediment fabric. This level is nested below the micrometer (microfabric) level that includes aggregates …