Download or read book Biogenic and Terrigenous Controls of Chemical Sedimentation in the Equatorial Pacific Over the Past 12 M Y written by Jessie O. Schroeder and published by . This book was released on 1995 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Equatorial Pacific Sediment Deposition During the Early to Middle Miocene written by Christine Marie Piela and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The equatorial Pacific is a major region of biological production in the world oceans and an important part of the global carbon cycle. Changes in climate during the Cenozoic (65 Ma to present) have impacted the carbon cycle, and it is important to assess these impacts. This study focuses on the primary productivity of the equatorial Pacific during the early to middle Miocene (24 - 12 Ma) as recorded by Deep Sea Drilling Project (DSDP) Site 574, and investigates the sedimentary components potentially linked to productivity: bio-Ba, bio-SiO2, Corg, CaCO3, and uranium, as well as detrital thorium to estimate clay-bound barium. Within this time frame the plate beneath Site 574 traveled northwesterly across the equator and allows a unique opportunity to monitor changes in productivity and the carbon cycle in this region. It is difficult to determine directly primary productivity from the sedimentary record because the preservation of different proxies for this parameter - Corg, bio-CaCO3, and bio-SiO2, can be highly variable. The variability has many causes, including nutrient recycling in the water column and the depth of the carbonate compensation depth (CCD), which prevents the preservation and ultimate burial of plankton debris at the seafloor. To interpret the production versus deposition rates during the early and middle Miocene, proxies were used in conjunction with direct measurements of biogenic remains. By determining the concentrations of biogenically produced barium (bio-Ba), which is less affected by degradation, it is evident that the mass of Corg produced was much greater than that preserved in the sediments. We observed higher deposition of bio-Ba and bio- SiO2 as the site was transported over the equatorial divergence by plate tectonics, as expected. In contrast, CaCO3, accumulation was low in the divergence region, and coincides with a dissolution event known from other site studies in the equatorial Pacific. The pattern of uranium deposition resembles CaCO3 and Corg, and average U concentrations suggest that it was primarily deposited as a trace element in the shell material of biogenic carbonate. Corg also resembles CaCO3 and appears to represent primarily a dissolution signal. Total uranium analysis proved to be a useful proxy for Corg and CaCO3 preservation, and analysis of detrital thorium (232Th) concentration suggests very limited terrigenous clay input. Comparison of the different proxies reveals carbonate preservation events, changes in Corg preservation, and changes in deposition as DSDP Site 574 migrated northwesterly across the equator.
Download or read book Indicators and Tracers of Ocean Chemistry Change Over the Pleistocene written by Rachel Oxburgh and published by . This book was released on 1996 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spatial and temporal distribution of biogenic carbonate and opal in deep sea sediments from the eastern equatorial Pacific written by M.E. WEBER and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Climatic and Oceanographic Controls on the Burial and Preservation of Organic Matter in Equatorial Pacific Deep sea Sediments written by Helen M. Perks and published by . This book was released on 1999 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Ocean Drilling Program written by Ocean Drilling Program and published by . This book was released on 1997-02 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical Controls on Palaeoceanographic Environmental Proxies written by William E. N. Austin and published by Geological Society of London. This book was released on 2008 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of our information about the evolution of Earth's ocean-climate system comes from the analysis of sediments laid down in the past. For example, the microfossil assemblage reflects the temperature, salinity and nutrient abundance of the water in which the organisms lived, while the chemical and isotopic composition of biogenic carbonates may be used to reconstruct past variations in the operation of the carbon cycle, as well as changes in ocean circulation. Nevertheless, understanding the link between these sediment variables (or 'proxies') and environmental conditions is not straightforward. This volume adopts a novel approach by bringing together palaeontologists, geochemists and palaeoceanographers, who contribute evidence that is required to better constrain these proxies. Topics include: (i) processes of biomineralization, and their effect on the chemical and isotopic composition of different organisms; (ii) proxy validation, including field, laboratory and theoretical studies; (iii) the links between modern and fossil organisms
Download or read book Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1990 with total page 1416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deep Sea Sediments written by H. Huneke and published by Elsevier. This book was released on 2011-02-08 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Deep-Sea Sediments' focuses on the sedimentary processes operating within the various modern and ancient deep-sea environments. The chapters track the way of sedimentary particles from continental erosion or production in the marine realm, to transport into the deep sea, to final deposition on the sea floor.
Download or read book Paleoredox and Color Change in Equatorial Pacific Sediments written by Wendy E. C. Kordesch and published by . This book was released on 2011 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Holocene Accumulation Rates of Pelagic Sediment Components in the Panama Basin Eastern Equatorial Pacific written by Stephen Atherton Swift and published by . This book was released on 1976 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Holocene bulk sediment and component accumulation rates were measured in twenty-eight piston and gravity cores taken from the floor of the western Panama Basin and on the surrounding ridges. Radiocarbon ages and oxygen isotope curves provided Holocene age control in nine cores. Time datums in nineteen other cores were inferred by correlation of calcium carbonate curves to the dated cores. Dry bulk densities were measured in ten cores and were estimated in the others by an empirical relationship between dry bulk density and the percentages of sand, clay, and calcium carbonate. Other studies of the textural, mineralogical and sand fraction composition of near surface sediments in these cores provided analyses which could be used to obtain accumulation rates for these components. A general similarity between the map pattern of surface productivity and the patterns of carbonate and opal accumulation rates suggests a first order control of biogenic sedimentation by fertility of surface waters. Accumulation rates of terrigenous components are highest near the continents; the map and depth patterns suggest dispersal by currents shallower than 2000 m or by winds. It is inferred from textural component accumulation rate patterns that no significant regional redistribution of sediment by winnowing occurred during the Holocene. Deposition from deep thermohaline circulation probably increased the accumulation rates of silt, clay, and opaline components in the gaps between the western and eastern troughs. Calcium carbonate accumulation rates at equal depths are generally lower within 250 km of the edge of the continental shelf. Below 2000 m in high productivity regions> 250 km from the shelf calcium carbonate accumulation rates decrease linearly with depth according to a gradient of -3.3 gm CaCO3/cm2/1000 yrs/ km. From this gradient, two independent estimates of the lysocline in this region, and a model of calcium carbonate accumulation, the average Holocene rate of supply of calcite from the surface is calculated to be 5-10 gm/cm2/1000 yrs.
Download or read book Global and regional controls on biogenic sedimentation written by and published by . This book was released on 1996 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cenozoic History and Paleoceanography of the Central Equatorial Pacific Ocean written by Tjeerd Hendrik Van Andel and published by . This book was released on 1975 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global and Regional Controls on Biogenic Sedimentation written by Erik Flügel and published by . This book was released on 1996 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical Geology written by Steven Earle and published by . This book was released on 2016-08-12 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a discount Black and white version. Some images may be unclear, please see BCCampus website for the digital version.This book was born out of a 2014 meeting of earth science educators representing most of the universities and colleges in British Columbia, and nurtured by a widely shared frustration that many students are not thriving in courses because textbooks have become too expensive for them to buy. But the real inspiration comes from a fascination for the spectacular geology of western Canada and the many decades that the author spent exploring this region along with colleagues, students, family, and friends. My goal has been to provide an accessible and comprehensive guide to the important topics of geology, richly illustrated with examples from western Canada. Although this text is intended to complement a typical first-year course in physical geology, its contents could be applied to numerous other related courses.
Download or read book Bioturbation of Recent Abyssal Sediments in the Eastern Equatorial Pacific written by Peter Franklin Bryant and published by . This book was released on 1977 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Orbital scale Controls on Biogenic Silica Accumulation in the Indian Sector of the Southern Ocean Over the Past 600 000 Years written by Emily Ann Kaiser and published by . This book was released on 2020 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instead of showcasing large glacial/interglacial variations in stratification, as expected, my opal mass accumulation record reveals a tight connection between biological production and orbital forcing. This novel record is interpreted to reflect precession driven changes in open ocean upwelling driven by westerly winds. These westerly winds, which are largely controlled by variations in radiative forcing, control biologic production on precession timescales. While most of the opal record displays clear responses to orbital precession (in both amplitude and timing), MIS 12 stands out as a glacial interval with high productivity. This unique production maximum during an extreme glacial climate may be caused by increased nutrient content of the waters being upwelled and/or increased silicic acid as a result of chemical weathering from Antarctica.
