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Paleomagnetism And Rock Magnetism Of Holocene Marine Sediments From Santa Catalina Basin
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Book Synopsis Paleomagnetism and Rock Magnetism of Holocene Marine Sediments from Santa Catalina Basin by : Daniel Lee Brandsma
Download or read book Paleomagnetism and Rock Magnetism of Holocene Marine Sediments from Santa Catalina Basin written by Daniel Lee Brandsma and published by . This book was released on 1985 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Deep-sea Sediment Paleomagnetism by : Sarah Elianna Strano
Download or read book Deep-sea Sediment Paleomagnetism written by Sarah Elianna Strano and published by . This book was released on 2014 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sedimentary records from the North Atlantic, instrumental in the development of modern paleo-geomagnetic concepts, show a highly variable field even during times of constant polarity. Yet, our understanding of how the magnetization is acquired in the sediments is poorly understood. Primary magnetizations preserved in deep-sea sediments are known to be acquired through a depositional or possibly, a post-depositional remanent magnetization (DRM or pDRM). A pDRM process implies that the magnetization is "locked-in" at depth creating an offset between the age of the magnetization and the age of sediment. The process is not currently accounted for in paleomagnetic records despite the wide use of magnetic records to elucidate the timing and rate of change of many paleomagnetic and environmental processes. This dissertation uses seven Northern North Atlantic (NNA) deep-sea sediment cores that were studied by alternating field demagnetization of natural and laboratory imposed remanence on uchannel samples, providing for detailed paleomagnetic and environmental magnetic records. These high-quality Holocene and deglacial magnetic data are combined with independent radiocarbon chronologies to better understand the: (1) magnetic acquisition process, (2) the NNA paleo-geomagnetic signal and (3) the influence of rock magnetic parameters on the sedimentary paleomagnetic record. Under the traditional paradigm of magnetostratigraphy, sediment deposition and magnetization are assumed to occur synchronously and with little to no signal attenuation. In Chapter 2, we compare independently dated Holocene paleomagnetic records from the seven deep-sea sediments cores across the North Atlantic with regional paleo-geomagnetic reconstructions derived from ultra-high resolution sediment records. We find variable delays between the timing of these records, consistent with a magnetization "locked-in" at depth and over an interval that results in smoothing of the geomagnetic signal. Optimization modeling of the post-depositional remanent magnetization (pDRM) accounts for both offset and some of this smoothing. It also demonstrates that the preserved magnetization is acquired ~20 cm below the sediment-water interface. Consistent with previous observations, this potentially ubiquitous process results in age offsets of 350-2000 years even in deep-sea sediment accumulation rates in excess of 10 cm/kyr that is rarely if ever accounted for in magnetostratigraphy or paleomagnetic records. In Chapter 3, we assume that the new "pDRM-corrected" chronologies developed for Chapter 2 more accurately represent each paleomagnetic record and create a NNA stack of both direction and intensity from ~15,000 years ago to present (NAPstack15). Uncertainty analyses and comparison to data derived from global field models at the same locations suggest that both, our directional and intensity stacks robustly capture the evolution of the mean geomagnetic field variations of the NNA. Broader regional comparisons with data from North America and Europe begin to define the evolution of the geomagnetic field during this time interval. Geomagnetic morphology and spatial/temporal variability can be roughly broken into three time intervals consistent with the evolution of global intensity and implicate the dynamics of the high-latitude Holocene flux patches as a source of this variability. We evaluate the effect of rock magnetic properties on the fidelity of the NNA paleomagnetic record from the Holocene through the last deglaciation. NNA records have been argued to consistently record high-quality paleomagnetic records over millennial to orbital time scales with little concern for lithologic variability resulting from glacial-interglacial environmental changes. We find that rock magnetic variability has little effect on the fidelity of the NNA's directional record, but has a variable and sometimes large influence on normalized remanence records, which are commonly used as a relative paleomagnetic intensity proxy. We find that the eastern NNA records are most affected by the use of different normalizers during the Holocene. The western NNA cores are more affected by the use of different normalizers during the deglacial period but to a lesser extent. The Iceland Basin cores are an exception, providing consistent normalized remanence records regardless of the normalizer during both the Holocene and deglacial interval. This likely reflects their proximity to Icelandic basaltic sources and the consistent magnetite grain-size regardless of physical grain-size that these sources provide.
Book Synopsis Paleomagnetism of Sedimentary Rocks by : Kenneth P. Kodama
Download or read book Paleomagnetism of Sedimentary Rocks written by Kenneth P. Kodama and published by John Wiley & Sons. This book was released on 2012-08-24 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the paleomagnetism of sediments and sedimentary rocks, how sediments and sedimentary rocks become magnetized, and how the physical and chemical processes involved can affect the accuracy of paleomagnetism. Topics covered include depositional and post-depositional remanence acquisition, the detection and correction of compaction-caused inclination shallowing, reduction diagenesis of magnetic minerals, chemical remagnetization, and rotation of remanence by grain-scale rock strain. The book also has a chapter on environmental paleomagnetism, including examples of the new technique of high-resolution rock magnetic cyclostratigraphy and its application to sedimentary sequences. By emphasising the accuracy of sedimentary paleomagnetism and the magnitude of post-depositional processes that can affect it, the book will be invaluable in the geologic interpretation of sedimentary paleomagnetic data. Paleomagnetism of Sedimentary Rocks will be welcomed by paleomagnetists, students of paleomagnetism and all Earth scientists who use sedimentary paleomagnetic data in their research. Additional resources for this book can be found at: www.wiley.com/go/kodama/paleomagnetism.
Download or read book California Geology written by and published by . This book was released on 1988 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A 37,000-year Record of Paleomagnetic and Environmental Magnetic Variability from Burial Lake, Arctic Alaska by : Jason Michael Dorfman
Download or read book A 37,000-year Record of Paleomagnetic and Environmental Magnetic Variability from Burial Lake, Arctic Alaska written by Jason Michael Dorfman and published by . This book was released on 2013 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Burial Lake sediments from the Noatak Basin in the northwest Brooks Range of Arctic Alaska (68.43°N, 159.17°W, 21.5 m water depth) provide the oldest continuous lacustrine record of paleo-environmental change and paleomagnetic secular variation (PSV) in eastern Beringia. A precise radiocarbon chronology, determined through accelerator mass spectrometry (AMS) allows us to independently constrain the region's climatic and geomagnetic evolution over the last ~37,000 years. Progressive alternating field (AF) demagnetization of u-channel samples and additionally acquired physical, geochemical, and rock-magnetic datasets, reveal three distinct lithologic subunits associated with the last glacial period (37.2 - 19.4 ka), the deglacial transition (19.4 - 9.8 ka), and the Holocene (9.8 ka - present). Rock magnetic variability suggests changes in sediment provenance associated with the transition from glacial to interglacial conditions. This is interpreted to result from a variable flux of aeolian derived sediment, and is supported by complimentary internal proxy data from Burial Lake. Other regional paleoclimate data, various glacial chronologies for the Brooks Range, and a relative sea level reconstruction facilitate a discussion of possible local, widespread, and far-field sources of dust, and the time-dependency of potential forcing mechanisms governing its production, availability, transport, and deposition. Results indicate an overall reduction in dust input from the glacial period to the Holocene that is largely attributed to increases in terrestrial and aquatic productivity, warming, and moisture availability, which limited widespread landscape deflation and production of dust. Subaerial continental shelves may have provided significant far-field sources of dust to interior Alaska during the glacial period, that were shut off by sea level inundation following the Last Glacial Maximum (LGM; 19 - 26.5 ka), further contributing to diminishing dust emissions. While glacial activity in the Brooks Range may provide local revenue of dust, activation of those deposits and timing of deposition in Burial Lake often appears to be more directly linked with general aridity, lack of vegetative cover, and increased windiness, rather than glacial advances or retreats. Despite this lithologic complexity, we isolate a stable, single-component characteristic remanent magnetization, carried predominately by low-coercivity (titano)magnetite in the pseudo single-domain (PSD) to multi-domain (MD) magnetic grain size range. We reconstruct directional paleomagnetic secular variation (PSV) over the full length of the record, and relative paleointensity (RPI) for the last ~14,700 years, which are consistent with available regional PSV records and continuous spherical harmonic model outputs. We observe only small deviations from geocentric axial dipole (GAD) predictions during the Holocene, while larger amplitude directional features are prevalent before 10 ka, and inclinations lay significantly shallower than GAD. While this may be related to lithology and the sediment magnetic acquisition process, regional records (including those derived from lava flows) indicate similar Holocene-Pleistocene discrepancies. Following on the "eccentric dipole" hypothesis, subdued secular variation and GAD-like behavior in the Pacific appears confined to the Holocene high-intensity state, showing greater variability as Pleistocene field strength diminishes, and/or the dipole axis is shifted away from the Pacific hemisphere. Long period trends in PSV from in the Alaskan Arctic are also similar in character to far-field sites (e.g., Hawaii and Siberia), suggesting large-scale coherent core-fluid flow regimes, expressed over surface geographical extents>5,000 km, and spanning Holocene-Pleistocene time intervals. The well-dated Burial Lake record fills a significant data gap in the growing Holocene paleomagnetic database, while allowing us to extend our understanding of PSV beyond the Holocene and into the Pleistocene, and continue the development of regional stratigraphic dating curves.
Book Synopsis A Paleomagnetic Study of Recent Sediments in the Santa Barbara Basin by : Rhea Lydia Graham
Download or read book A Paleomagnetic Study of Recent Sediments in the Santa Barbara Basin written by Rhea Lydia Graham and published by . This book was released on 1978 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleomagnetism and Environmental Magnetism of Sediment Cores from ODP Leg 169S, Saanich Inlet, British Columbia by : Adam Hershel Harris
Download or read book Paleomagnetism and Environmental Magnetism of Sediment Cores from ODP Leg 169S, Saanich Inlet, British Columbia written by Adam Hershel Harris and published by . This book was released on 2002 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Index to Graduate Theses and Dissertations on California Geology, 1973-1989 by :
Download or read book Index to Graduate Theses and Dissertations on California Geology, 1973-1989 written by and published by . This book was released on 1978 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rock Magnetic and Paleomagnetic Studies of Marine Sediments from the Central and Western North Pacific: Stratigraphic and Paleoceanographic Implications by : Seong-Jae Doh
Download or read book Rock Magnetic and Paleomagnetic Studies of Marine Sediments from the Central and Western North Pacific: Stratigraphic and Paleoceanographic Implications written by Seong-Jae Doh and published by . This book was released on 1987 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Geology and Tectonics of Santa Catalina Island and the California Continental Borderland by :
Download or read book Geology and Tectonics of Santa Catalina Island and the California Continental Borderland written by and published by . This book was released on 2004 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Preliminary Index to Graduate Theses and Dissertations on California Geology, 1982-1988 by :
Download or read book Preliminary Index to Graduate Theses and Dissertations on California Geology, 1982-1988 written by and published by . This book was released on 1989 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleomagnetism, Rock Magnetism, and Diagenesis in Hemipelagic Sediments from the Northeast Pacific Ocean and the Gulf of California by : Robert Karlin (oceanographer.)
Download or read book Paleomagnetism, Rock Magnetism, and Diagenesis in Hemipelagic Sediments from the Northeast Pacific Ocean and the Gulf of California written by Robert Karlin (oceanographer.) and published by . This book was released on 1983 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleomagnetic and Rock Magnetic Analysis of Upper Cretaceous Synorogenic Conglomerates From the Cordilleran Foreland Basin, Utah; Middle Triassic Moenkopi Formation From the Petrified Forest National Park, Arizona; and Pseudotachylytes From the Albany-Fraser Orogenic Belt, Southwest Australia by : Ziaul Haque
Download or read book Paleomagnetic and Rock Magnetic Analysis of Upper Cretaceous Synorogenic Conglomerates From the Cordilleran Foreland Basin, Utah; Middle Triassic Moenkopi Formation From the Petrified Forest National Park, Arizona; and Pseudotachylytes From the Albany-Fraser Orogenic Belt, Southwest Australia written by Ziaul Haque and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation consists of three induvial projects that focus on the application of paleomagnetism and rock-magnetism to decipher the magnetic mineralogy and magnetic remanence carrier, magnetization acquisition processes, magnetic petrofabric to understand the depositional and post-depositional deformation fabrics, and to construct a high-resolution magnetochronology of studied sedimentary rock sequences. Project 1 addresses the magnetic polarity stratigraphy of Late Cretaceous long run-out coarse-grained facies exposed in the Cordilleran Foreland basin in northeast Utah. For an improved understanding of kinematic history of the Sevier fold-thrust belt, depositional ages of syntectonic units and the integration of geologic and geochronologic constraints are important. To construct an independent age constraint for the Upper Cretaceous synorogenic units from the Cordilleran foreland basin in northeast Utah, we have sampled the fine-grained, hematitic interbeds in the Upper Cretaceous Echo Canyon Conglomerate and Weber Canyon Conglomerate. Results show that hematitic, fine-grained sandstone to siltstone intervals carries a geologically stable magnetization with directions and polarity consistent with the Late Cretaceous geomagnetic field. Magnetic polarity data coupled with the existing palynologic ages indicate that these coarse-grained strata in the northeast Utah were most likely deposited over the time span of the magnetic polarity Chron (C) 34n to C33r interval, which includes the Santonian-Campanian stage boundary (ca. 83.4 Ma/83.1 Ma) and the younger C33r to C33n interval. The new age constraints demonstrate a complete temporal overlap between proximal and distal coarse-grained deposits in this part of the Cordilleran foreland basin suggesting a coeval sedimentation in both the proximal and distal parts linked with the active thrust displacement and rapid hinterland exhumation. Project 2 involves establishing a robust age constraint for the Triassic Moenkopi Formation intersected in the Colorado Plateau Coring Project Phase 1. Moenkopi Formation strata in the Little Colorado River drainage basin preserves one of the richest non-marine macrofloral and vertebrate fossil assemblages from the whole of North America, and a robust age constraint of this sequence is important to estimate the ages of its constituent fossil assemblages, document key biotic events, and for lithologic and biostratigraphic correlation across continents. To construct a highresolution magnetic polarity timescale for the Moenkopi Formation, samples were collected from the entire interval of Moenkopi Formation rocks intersected in two continuous cores (CPCP-1A and CPCP-2B). Demagnetization data yield a well-defined, interpretable paleomagnetic results, and six normal and reverse polarity couplets were identified in both cores, which are denoted from youngest to oldest, MF1n to MF6r. CA-TIMS calibrated CPCP-1 magnetozones exhibited a well-defined correlation with the astronomically tuned polarity timescale for the Middle Triassic deep-marine Guandao (GD) section of South China, and ties the magnetozone MF1n with GD8 and MF6r with GD2r, and implies that the Moenkopi Formation spans, at most, the earliest Anisian (Aegean) to latest Anisian (Illyrian)/ earliest Ladinian stages (ca. 246.8 Ma to 241.5 Ma). This refined age estimate for the Moenkopi Formation suggests that the vertebrate fossil assemblages preserved in east-central Arizona are millions of years (minimally 3 - 4 Ma) younger and are all Anisian in age. Project 3 involves the magnetic petrofabric characterization of fault generated pseudotachylyte vein rocks and adjacent Mesoproterozoic host rock from the Cape Arid region of southwest Australia. We have examined the magnetic properties of faultgenerated pseudotachylyte (PST) veins, typically less than a cm in width, and surrounding granitic host rocks (HR) from the mid-Proterozoic Albany Fraser orogenic belt of the Yilgarn Craton. Analysis showed that the PST and HR samples contain contrasting rock-magnetic properties and magnetic fabrics. Microscopic observations of pseudotachylyte rocks show grainsize reduction, enhancement of specific mineral phases (e.g., magnetite and biotite) and grain elongation. Rock magnetic data suggest an overall enhancement of ferrimagnetic (s.l.) phases, largely magnetite, in the pseudotachylyte rocks, and the magnetic fabric is primarily controlled by the shape prepared orientation of magnetite grains. Paleomagnetic results yield highly dispersed magnetization vector directions, and unable to provide a geologically significant interpretation. PST magnetofabric shows a steep foliation suggesting a vertical slip, and a NESW oriented shear suggests that generation of these vein rocks are unrelated to the Albany-Fraser Orogeny and may plausibly represent the early-stage deformation related to the breakup of supercontinent Rodinia at ca. 750 Ma.
Book Synopsis Bibliography and Index of Geology by :
Download or read book Bibliography and Index of Geology written by and published by . This book was released on 1989 with total page 1576 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleomagnetism and Rock Magnetism of Powder River Basin Clinker, Northeastern Wyoming and Southeastern Montana by : Alison H. Jones
Download or read book Paleomagnetism and Rock Magnetism of Powder River Basin Clinker, Northeastern Wyoming and Southeastern Montana written by Alison H. Jones and published by . This book was released on 1983 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleomagnetic Secular Field Variation and Rock Magnetism of Some Early Holocene ( by : Bjarne Sven Gustav Almqvist
Download or read book Paleomagnetic Secular Field Variation and Rock Magnetism of Some Early Holocene ( written by Bjarne Sven Gustav Almqvist and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Study area : Strawberry Creek area approx. 30 km. west of Thunder Bay along Highway 17.
Book Synopsis Proceedings of the Ocean Drilling Program by : Ocean Drilling Program
Download or read book Proceedings of the Ocean Drilling Program written by Ocean Drilling Program and published by . This book was released on 1992 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
