Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 38 for “"tuffs"”.
-
Electrical resistivity changes in tuffs
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1979.
-
Correlation of ash-flow tuffs, San Juan volcanic field, Colorado
Includes bibliographical references (pages 171-174).
-
Correlation of ash-flow tuffs, San Juan volcanic field, Colorado
Includes bibliographical references (pages 171-174).
-
Comparison of Breien and Canonball Volcanic Tuffs in Southern North Dakota
<p>Volcanic tuffs of Cretaceous age are found sandwiched in many outcrops in southwestern North Dakota. The lateral extent of many of these tuffs has been mapped, but distinguishing discrete tuffs is a work in progress. This report looks at two tuffs found along the Cannonball River south of …
-
Investigation of Natural Zeolitic Tuffs on their Ability for Sewage Cleaning Purposes
… material used was brownish and reddish zeolitic tuffs. Both materials were found to be very different from each other in their chemical and mineralogical compositions. The untreated sample of reddish zeolitic tuff showed a very high capacity for ammonium adsorption (46g/kg) from an ammonium …
-
Petrogenic comparison of early crystal-poor ash-flow tuffs, San Juan volcanic field, south-central Colorado, A
Includes bibliographical references (pages 195-203).
-
Investigating Microbial Trace-fossils and Abiotic Alteration in Hydrovolcanic Tuffs of the Fort Rock Volcanic Field, Oregon
Microbial ichnofossils in volcanic rocks provide a significant record of subsurface microbes and potentially extraterrestrial biosignatures. Here, the textures, mineralogy, and geochemistry of two continental basaltic hydrovolcanic deposits - Reed Rocks and Black Hills - in the Fort Rock Volcanic …
-
Paleomagnetic and AMS results from Oligocene ash-flow tuffs of the eastern San Juan Mountains : implications for the evolution of the western margin of the San Luis Basin, northern Rio Grande Rift
… ca. 26 Ma in the Cordillera. Oligocene ash-flow tuffs exposed in the eastern San Juan Mountains and along the western margin of the SLB provide an excellent opportunity to study the kinematic history of the northern Rio Grande rift using paleomagnetism. Outflow deposits of ash-flow tuffs are …
-
Single- and cross-hole pneumatic injection tests in unsaturated fractured tuffs at the Apache Leap Research Site near Superior, Arizona
… in fluid flow through unsaturated, fractured tuffs. It summarizes the experimental design of single- and cross-hole pneumatic injection tests, including borehole configuration and testing schedules, data collection system, interpretive models developed and tested, data, and conclusions. …
-
Petrography and geochemistry of hydrothermal breccias hosted in the Schrikkloof Formation (Rooiberg Group), north of Modimolle, South Africa
The Schrikkloof Formation, composed of rhyolites, tuffs and hydrothermal breccias, is the youngest rhyolitic volcanic sequence of the Rooiberg Group of the Bushveld Igneous Complex and is known to host polymetallic Sn-F-REE. The aim and objective of this research is to understand whether the …
-
Volcanic and sedimentary processes in phreatomagmatic volcanoes
… of crater deposits formed a pile of massive tuffs above which subsequent surge and airfall activity deposited a nestedg inner crater rim. The Medano tuff-ring Tenerife, is a phreatomagmatictype structure whose crater contains reworked tuffs deposited during subsidence into the underlying …
-
The Provenance of Eocene Tuff Beds in the Fossil Butte Member of the Green River Formation of Wyoming: Relation to the Absaroka and Challis Volcanic Fields
… Formation at Fossil Basin, preserve ash fall tuffs deposited in ancient Fossil Lake. 40Ar/39Ar dating of sanidine yielded eruptive ages of 51.29 ± 1.29 Ma and 52.20 ± 3.08 Ma for two of the tuff beds within Fossil Basin. Immobile element and mineral compositions of Fossil Basin tuffs indicate …
-
Origin and Diagenesis of Lacustrine Sediments of the Late Oligocene Creede Formation, Southwestern Colorado
… sequences of authigenic silicates in tuffs reflect alteration of silicic-intermediate vitric tuff within an elevated geothermal gradient (90$\sp\circ$-150$\sp\circ$C/km). The abundance of clinoptilolite - Al-smectite in drillcore CCM-2 is consistent with diagenetic waters having low to …
-
Microbial transport in volcanic tuff Rainier Mesa, Nevada test site
… bacterial transport with water in deep fractured tuffs, flow water and six rock samples were taken progressively farther from a deep subsurface fracture flow system for microbiological and geological comparisons. Differences in the composition of microbiota among sites appeared to be the result of …
-
Gold-quartz vein mineralization in Stanly County, North Carolina
… lie subparallel to schistosity in the Andesitic Tuffs Unit of the Upper Volcanic Sequence or Millingport Formation. Lower greenschist grade regional metamorphism at 483 m.y. has slightly altered the tuffs but little affected the veins. The veins are >95% milky to glassy quartz with minor …
-
Heat pipe effect in porous medium
… characteristics of the fractured porous tuffs at Yucca Mountain, Nevada was conducted. The effects of different fracture and matrix properties including permeability, thermal conductivity, specific heat, porosity, and tortuosity on heat pipe performance in the vicinity of the waste …
-
Generalised predictive control : a study and application
… (GPC) method derived by Clarke, Mohtadi and Tuffs in the mid eighties. GPC is an adaptive predictive control algorithm, of which there are number, and has proven to be one of the more popular variants having been applied to various control applications. The theory of the GPC method is studied …
-
Equilibrium studies of ion sorption on zeolitized tuff from Rainier Mesa, Nye County, Nevada
… tuff and the most common zeolite present in the tuffs could be made. Along with the geochemical parameters calculated, an interpretation of the qualitative differences in the partitioning behavior of these ions was made. This study indicates a markedly different behavior between the two cations, …
-
Mechanical properties of tuffaceous rocks under triaxial conditions
… of the mechanical properties of the tuffs which comprise Yucca Mountain. The study tested specimens of TCw tuff in triaxial compression to observe the effects of confining pressure, saturation, strain rate, and anisotropy on the compressive strengths and Young's Moduli of the …
Page 1 of 2