Download or read book Crustal Accretion at a Spreading Rate End member the Mid Cayman Spreading Center written by Jennifer Logan Harding and published by . This book was released on 2019 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean crustal accretion is an important Earth process, affecting the global heat budget, geochemical cycles, and life on Earth. New crust is produced at divergent plate boundaries, or spreading centers, at a range of full plate separation rates from ultraslow spreading rates of 15 mm/yr, to fast spreading rates of 75 mm/yr. Oceanic crustal structure, lithology, and thickness vary with spreading rate, and ultraslow-spreading centers accrete some of the thinnest and most heterogeneous crust on Earth. In order to investigate fundamental tectonic, magmatic and accretionary processes that underlie these observations, we study one of the slowest-spreading centers in the world, the Mid-Cayman Spreading Center (MCSC), situated between the North American Plate and the Caribbean Plate in the Caribbean Sea. We image the new oceanic crust formed at the MCSC by modeling wide-angle refraction seismic data, gravity data, and geochemistry of seafloor rocks. Seismic images of P-wave velocity (Vp) reveal very heterogeneous structure both parallel and perpendicular to the axial valley. A low Vp zone ~5 km beneath an off-axis massif that hosts a hydrothermal vent field likely represents fracturing associated with hydrothermal circulation, and possibly intruded magmatic sills. In order to constrain the lithology of the crust, we model amplitudes of seismic refraction data and construct gravity profiles. We find that the thickness of the igneous crust varies from ~0- 6 km with a mean of ~3 km, where gabbro within a matrix of variably serpentinized mantle is distributed unevenly along the spreading center. Geochemical modeling of incompatible element concentrations in basalts provides estimates of the magmatic budget of the MCSC and two other spreading segments with faster spreading rates. The MCSC has a modeled melt thickness of ~2.8 km, with suppressed melting to ~12 km depth. These results support the hypothesis that there is increased surface cooling of the lithosphere at ultraslow-spreading rates, which reduces melt supply, and that these magmatic processes vary smoothly with spreading rate. Variability of ultraslow-spread crustal thickness can be explained by a segment-scale spatiotemporal fluctuation of lithospheric deformation and melt delivery, with an average of ~2 km of serpentinized mantle within the upper lithosphere

Download or read book Crustal Accretion and Evolution at Slow and Ultra slow Spreading Mid ocean Ridges written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Funding was provided by the National Science Foundation through Contract No. OCE-9300450 and by the Joint Oceanographic Institutions through Subcontract No. JSC1-00.

Download or read book Crustal Structure in Areas of Active Crustal Accretion written by Leonard Dale Bibee and published by . This book was released on 1979 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deep Drilling Results in the Atlantic Ocean written by Manik Talwani and published by . This book was released on 1979 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crustal Accretion at Intermediate Spreading Rates written by Ana Lucia Goncalves Macario and published by . This book was released on 1995 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crustal Accretion at the Intermediate Spreading Rate Southeast Indian Ridge written by L. Ying Ma and published by . This book was released on 1997 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Collected Reprints Woods Hole Oceanographic Institution written by Woods Hole Oceanographic Institution and published by . This book was released on 1981 with total page 1360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains also Annual report.

Download or read book Duration Rates and Patterns of Crustal Growth at Slow spreading Mid ocean Ridges written by Craig B. Grimes and published by ProQuest. This book was released on 2008 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation addresses temporal and spatial characteristics of magmatic and tectonic accretion processes occurring at mid-ocean ridges during formation of new ocean lithosphere. The accretion histories of plutonic crust recovered by deep drilling of footwalls to large-displacement normal faults at three locations on the MAR are emphasized. Pb/U zircon dating of evolved gabbros and oceanic plagiogranites show that magmatic accretion typically occurs over 100-200 kyr. Magmatic accretion occurs by emplacement of many short-lived intrusive pulses that are focused at different depths within the crust and mantle. During formation of the Atlantis Massif core complex (30° N, MAR), spreading may have been partitioned up to 100% on the North American plate for at least 200 kyr, implying crustal accretion was highly asymmetric. Cooling rates of 1000-2000° C/m.y. over 900-200° C are documented at Atlantis Massif and two locations from 14-16°N, MAR, consistent with rapid denudation of the footwall sections to the seafloor following emplacement. Spreading rates combined with the time interval over which cooling to

Download or read book Studies of Melt Migration and Crustal Accretion at Spreading Centers Based on Seismic Imaging and Models of Mantle Flow written by Wusi Su and published by . This book was released on 1995 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Insights Into Accretion and Cooling of Lower Ocean Crust at Ultraslow and Fast spreading Mid ocean Ridges written by Christopher James Doorn and published by . This book was released on 2022 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mid-ocean ridges are the primary divergent tectonic margins and generate the ocean crust, which covers ~60% of Earth’s surface. The gabbroic lower ocean crust hosts lithologic and structural diversity varying with spreading rate and magma supply. This dissertation examines lower crustal accretion at ultraslow- and fast-spreading ridges to better constrain crustal accretion and cooling across spreading rates. Trace element compositions of zircon from Atlantis Bank (Southwest Indian Ridge) characterize the final stages of magmatism and the thermal architecture in the lower crust produced along an ultraslow-spreading ridge. U-Pb zircon dates of evolved gabbroic rocks from the fast-spread lower crust at Pito Deep (East Pacific Rise) reveal significant off-axis magmatism, implying locally robust magmatism and relatively slow cooling of this nascent ocean crust. Textural characteristics of gabbroic rocks from Pito Deep highlight the lateral complexity of the fast-spread lower crust, and record increasing degrees of magmatic strain with depth. Synthesizing textural data, U-Pb geochronology, mineral chemistry, and magnetic data from Pito Deep supports a pulsed gabbro glacier flow process for generating the lower ocean crust at magmatically robust fast-spreading ridges.

Download or read book Crustal Accretion and Evolution at Slow and Ultra slow Spreading Mid ocean Ridges written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Funding was provided by the National Science Foundation through Contract No. OCE-9300450 and by the Joint Oceanographic Institutions through Subcontract No. JSC1-00.

Download or read book The Role of the Axial Melt Lens in Crustal Accretion at Fast spreading Mid ocean Ridges written by Matthew Phillip Loocke and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Geological Record of Oceanic Crustal Accretion and Tectonism at Slow Spreading Ridges written by and published by . This book was released on 1996 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Gulf of Mexico Sedimentary Basin written by John W. Snedden and published by Cambridge University Press. This book was released on 2019-11-21 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and richly illustrated overview of the Gulf of Mexico Basin, including its reservoirs, source rocks, tectonics and evolution.

Download or read book Geological Society of America Bulletin written by Geological Society of America and published by . This book was released on 1978 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. 1-44 include Proceedings of the annual meeting, 1889-1933, later published separately.

Download or read book Earth History and Palaeogeography written by Trond H. Torsvik and published by Cambridge University Press. This book was released on 2017 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a complete Phanerozoic story of palaeogeography, using new and detailed full-colour maps, to link surface and deep-Earth processes.

Download or read book Modern Ocean Floor Processes and the Geological Record written by Rachel A. Mills and published by Geological Society of London. This book was released on 1998 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: