Isotopic Studies Of Hydrothermal Alteration And Large Volume Cold Springs In Fractured Volcanic Rocks Mount Lassen Region California
DOWNLOAD
Download Isotopic Studies Of Hydrothermal Alteration And Large Volume Cold Springs In Fractured Volcanic Rocks Mount Lassen Region California PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Isotopic Studies Of Hydrothermal Alteration And Large Volume Cold Springs In Fractured Volcanic Rocks Mount Lassen Region California book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Isotopic Studies Of Hydrothermal Alteration And Large Volume Cold Springs In Fractured Volcanic Rocks Mount Lassen Region California
DOWNLOAD
Author : Timothy Patrick Rose
language : en
Publisher:
Release Date : 1994
Isotopic Studies Of Hydrothermal Alteration And Large Volume Cold Springs In Fractured Volcanic Rocks Mount Lassen Region California written by Timothy Patrick Rose and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with categories.
Dissertation Abstracts International
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1995
Dissertation Abstracts International written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1995 with Dissertations, Academic categories.
Index To Graduate Theses And Dissertations On California Geology 1990 Through 1997
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1998
Index To Graduate Theses And Dissertations On California Geology 1990 Through 1997 written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Dissertations, Academic categories.
Comparative Isotope Hydrology Study Of Groundwater Sources And Transport In The Three Cascade Volcanoes Of Northern California
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2001
Comparative Isotope Hydrology Study Of Groundwater Sources And Transport In The Three Cascade Volcanoes Of Northern California written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
Quaternary-age volcanic peaks of Mt. Lassen, Mt. Shasta, and Medicine Lake Volcano preferentially recharge and transport large volumes of annual precipitation into mega- scale channels hosted in underlying volcanic layers. At the terminus of laterally extensive lava flows, or in deep incisions of these layers, groundwater emerges as large volume cold springs. The combined discharge of these springs contributes half the annual storage capacity of Shasta Reservoir, and is utilized to generate 2000 gigawatts of hydroelectric power each year. Moreover, the springs provide a natural habitat for many rare and endangered species. In the Hat Creek Valley, located north of Mt. Lassen, Rose et al. (1996) showed that the low d 18 O discharge of large volume springs at Rising River and Crystal Lake originates from snow melt in the high elevation, high precipitation region surrounding Lassen Peak. Groundwater transport in this basin is enhanced by the occurrence of the Quaternary Hat Creek basalt flow, which extends nearly the entire length of Hat Creek Valley. In contrast, the d 18 O values of large- volume springs that discharge in the Mt. Shasta region indicate a larger percentage of local recharge at lower elevations since the high elevation snow melt on the volcano is depleted by>1 per mil relative to the largest springs. The d 18 O value of the Fall River Springs (FRS) system is similar to small springs that occur at high elevations on Medicine Lake Volcano. The large volume of the FRS discharge coupled with a lack of surficial drainages in this area indicates that a large percentage of the annual precipitation over an750 mi 2 area of the Medicine Lake volcanic plateau goes to recharge the FRS aquifer system. Groundwater transport to the FRS is enhanced by the occurrence of the 10 kyr Giant Crater lava flow, a single geologic unit that extends from the base of Medicine Lake Volcano to the FRS.many of the large volume springs in the southern Cascade Range. For example, the radiocarbon concentration in Rising River Springs is 80 pmc, which indicates at least 20% of its dissolved inorganic carbon is derived from a magmatic source in the Lassen region. The radiocarbon activity in the FRS is as low as 73 pmc, indicating a minimum contribution of 27% magmatic CO2 from Medicine Lake volcano. Magmatic CO2 fluxes in the Shasta region are highest around the base of the volcano, where low- volume, CO2 -rich,14 C- absent soda springs occur. Relatively large quantities of magmatic CO2 are observed in the Big Springs of the McCloud River, which have a d 18 O signature consistent with low elevation recharge in the Shasta region.relative to Mt. Lassen and Medicine Lake Volcano reflect significant differences in the geomorphology of the volcanoes. In particular, the composite nature of the Shasta stratocone tends to limit the depth of groundwater recharge, confining the majority of groundwater flow to the shallowest layers, which tend to be of more local extent. The lower permeability of the composite cone also acts as a trap for magmatic CO2 emissions, generally limiting the gas discharge to localized fracture zones at lower elevations. At Mt. Lassen and Medicine Lake Volcano, groundwater recharge occurs primarily at high elevations, along vertical fracture systems with high permeabilities. These features, combined with laterally extensive basalt flows, act to focus groundwater transport deeper and over longer lateral distances. The magmatic CO2 dissolution process probably occurs in close proximity to the geothermal systems at Lassen and Medicine Lake, where CO2 gas escaping along deep fractures encounters downward percolating groundwater.
American Doctoral Dissertations
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1994
American Doctoral Dissertations written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Dissertation abstracts categories.
Stable Isotope Studies Of Some Active Hydrothermal Systems
DOWNLOAD
Author : Steven J. Lambert
language : en
Publisher:
Release Date : 1976
Stable Isotope Studies Of Some Active Hydrothermal Systems written by Steven J. Lambert and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1976 with Geochemistry categories.
The Isotope Geochemistry Of Abyssal Peridotites And Related Rocks
DOWNLOAD
Author : Jonathan E. Snow
language : en
Publisher:
Release Date : 1993
The Isotope Geochemistry Of Abyssal Peridotites And Related Rocks written by Jonathan E. Snow and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Basalt categories.
This dissertation studies several aspects of the formation of the Earth's oceanic mantle and crust, using a variety of geologic techniques, principally major elements, radiogenic isotopes and trace elements, but including petrography, mineral chemistry, x-ray diffraction, seafloor geomorphology, and analysis of the tectonics of fracture zones. The first chapter is an introduction to the problems to be addressed in this work. The second chapter examines the composition of basalts erupted near the Atlantis II Fracture Zone on the Southwest Indian Ridge. Trends in major element compositions of those basalts can be related directly to the nearby presence of the fracture zone. The effects of mantle composition and crustal level lateral transport of magma in the rift system can be ruled out by the analysis of isotopes and the geomorphology of the fracture zone floor. This is the best demonstration to date of a transform fault effect on basalt compositions. In trying to quantify putative transform fault effects documented at other fracture zones, no systematic correlation of transform offset age with mantle temperature change can be found, suggesting that mantle composition and lateral transport phenomena play a larger than expected role in the evolution of those areas. The third chapter relates to oceanic mantle rocks as they are altered at or near the Earth's surface. The major elements which make up abyssal peridotites are extensively redistributed by the alteration they have undergone. Mg is shown to be extracted from the peridotites, and a variety of trace elements added. This elemental redistribution is taken as evidence for extensive Mg transport by circulating waters. Since the solubility of Mg-bearing minerals in hydrothermal solutions is quite limited, much lower temperatures and much higher water /rock ratios are required to explain the major element compositions of the peridotites than had previously been assumed. The behavior of the Nd, Sr and Os isotopic systems during seafloor alteration was also studied. The isotope systematics of these rocks strongly support the hypothesis of high water /rock ratios in the formation of serpentinized abyssal peridotites. Nonetheless, Nd and Sr reside in a phase which is resistant to alteration (clinopyroxene) and the concentration of Os is high relative to that of seawater, so that it too appears resistant to alteration. Primary mantle isotopic signatures may be obtained from abyssal peridotites by careful analysis, even of extremely weathered rocks. Radiogenic strontium in excess of what could be introduced by seawater contamination or in situ radiogenic growth in a reasonable period of time was also found. These observations confirm earlier work which had been discredited for many years. The only plausible mechanism for the formation of this "orphan" S7Sr is that it is introduced as part of a sedimentary component which infiltrates the rock during metamorphism and/ or weathering. The 87Sr may be contained by or sorbed onto extremely fine clay particulates, or colloidal suspensions, as opposed to the dissolved ionic Sr which is normally thought of as characterizing the Sr isotopic composition of seawater. The high water/rock ratios required by the bulk isotopic analysis, as well as the pervasive elemental redistribution arguing for extensive near-surface weathering at high water /rock ra.tios strongly support this hypothesis. Given pervasive percolation of water throughout the samples, sufficient radiogenic, sediment-derived strontium may be drawn deep into the crust in the course of its weathering to cause such high B7SrfB6Sr ratios. The fourth chapter deals exclusively with primary mantle isotopic information from abyssal peridotites. This is the first study which has attempted to relate the Os isotopic system in the oceanic mantle to other isotopic systems and to trace elements. It is possible, with some extreme assumptions, to model the range of Os isotopes in the oceanic mantle alone in a standard model of formation of the depleted mantle by extraction of the crust. The additional constraints provided by the study of Nd isotopes in depleted mantle rocks from the oceans show that partial melt extraction and the formation of a depleted reservoir alone are not sufficient to account for the range of both N d and Os isotopes in the Earth's mantle. Possible mechanisms for the decoupling of the Os and Nd isotopic systems include elemental fractionation via the porous flow of basalt through the mantle, mantle metasomatism, recycling of a subducted component in the mantle and core formation. The core extraction model is pursued in some detail. Such core extraction models can account for the distributions and isotopic compositions of compatible and incompatible trace elements in the Earth's mantle, but they are highly non-unique, and thus difficult to test
Petrology And Mineral Alteration In Hydrothermal Systems
DOWNLOAD
Author : Agnes G. Reyes
language : en
Publisher:
Release Date : 2000
Petrology And Mineral Alteration In Hydrothermal Systems written by Agnes G. Reyes and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Hydrothermal resources categories.
Light Stable Isotope Study Of The Roosevelt Hot Springs Thermal Area Southwestern Utah
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2005
Light Stable Isotope Study Of The Roosevelt Hot Springs Thermal Area Southwestern Utah written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
The isotopic composition of hydrogen, oxygen, and carbon has been determined for regional cold springs, thermal fluids, and rocks and minerals from the Roosevelt Hot Springs thermal area. The geothermal system has developed within plutonic granitic rocks and amphibolite facies gneiss, relying upon fracture-controlled permeability for the migration of the thermal fluids. Probably originating as meteoric waters in the upper elevations of the Mineral Mountains, the thermal waters sampled in the production wells display an oxygen isotopic shift of at least +1.2. Depletions of delta /sup 18/O in wole rock, K-feldspar, and biotite have a positive correlation with alteration intensity. W/R mass ratios, calculated from the isotopic shifts of rock and water, range up to 3.0 in a producing horizon of one well, although the K-feldspar has experienced only 30% exchange with the thermal waters. While veinlet quartz has equilibrated with the thermal waters, the /sup 18/O values of K-mica clay, an alteration product of plagioclase, mimic the isotopic composition of K-feldspar and whole rock. This suggests that locally small W/R ratios enable plagioclase to influence its alteration products by isotopic exchange.
Stable Isotope Investigation Of Fluids And Water Rock Interaction In The Roosevelt Hot Springs Thermal Area Utah
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2005
Stable Isotope Investigation Of Fluids And Water Rock Interaction In The Roosevelt Hot Springs Thermal Area Utah written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
Carbon-hydrogen-oxygen isotope compositions have been measured in regional cold waters, geothermal fluids, and hydrothermally altered rocks from the Roosevelt Hot Springs geothermal area. These data have been used, in conjunction with other geological and geochemical data from this geothermal system, to place some limits on the origin of geothermal fluids and reservoir carbon, the fluid recharge area, physical-chemical environment of hydrothermal alteration, and relative permeability of the geothermal system. The similarity of hydrogen isotope compositions of local meteoric water and geothermal reservoir fluid indicate that the geothermal fluids are virtually entirely of surface derivation. An isotopically reasonable source area would be the Mineral Mountains directly to the east of the Roosevelt system. Hydrothermal calcite appears to be in isotopic equilibrium with the deep reservoir fluid. The deltaC/sup 13/ values of deep calcites and T- pH-f0/sub 2/ conditions of the reservoir defined by measured temperature, fluid chemistry, and alteration mineralogy fix the delta/sup 13/C value of the geothermal system to -5 to -6.5% (PDB). These values do not unambiguously define any one source or process, however. There is a relatively small increase in /sup 18/O of geothermal fluids relative to their cold surface water precursors and significant /sup 18/O depletion accompanying hydrothermal alteration of the granitic host rock. These isotopic shifts indicate a high ratio of geothermal fluid to altered rock for the geothermal system, implying relatively rapid (geologically) recirculation rates and significant permeability of the geothermal system.