Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Rock Magnetism Of Hematitic "Bombs" From The Araguainha Impact Structure, Brazil, Luigi Jovane, Elder Yokoyama, Takele Seda, Russ F. Burmester, Ricardo I.F. Trindade, Bernard A. Housen
Rock Magnetism Of Hematitic "Bombs" From The Araguainha Impact Structure, Brazil, Luigi Jovane, Elder Yokoyama, Takele Seda, Russ F. Burmester, Ricardo I.F. Trindade, Bernard A. Housen
Geology Faculty Publications
Hematite impact “bombs” are one of the most striking (and enigmatic) features of the large Araguainha impact structure in central Brazil. They have both porous or massive textures, elongated shapes from 5 to 50 cm in diameter, and botryoidal textures that suggest hydrothermal origin. Some authors have considered these objects as a possible analog of hematite nodules found in Mars, and consequently related to a hydrothermal system. Here we report rock magnetic measurements, X-ray diffraction and Mössbauer spectra for both massive and porous samples for a detailed description of the hematite. Room temperature magnetic measurements, including hysteresis loops, back-field and …
The 2007 Nazko, British Columbia, Earthquake Sequence: Injection Of Magma Deep In The Crust Beneath The Anahim Volcanic Belt, J. F. Cassidy, N. Balfour, C. Hickson, H. Kao, R. White, Jacqueline Caplan-Auerbach, S. Mazzotti, G. C. Rogers, I. Al-Khoubbi, A. L. Bird, L. Esteban, M. Kelman, J. Hutchinson, D. Mccormack
The 2007 Nazko, British Columbia, Earthquake Sequence: Injection Of Magma Deep In The Crust Beneath The Anahim Volcanic Belt, J. F. Cassidy, N. Balfour, C. Hickson, H. Kao, R. White, Jacqueline Caplan-Auerbach, S. Mazzotti, G. C. Rogers, I. Al-Khoubbi, A. L. Bird, L. Esteban, M. Kelman, J. Hutchinson, D. Mccormack
Geology Faculty Publications
On 9 October 2007, an unusual sequence of earthquakes began in central British Columbia about 20 km west of the Nazko cone, the most recent (circa 7200 yr) volcanic center in the Anahim volcanic belt. Within 25 hr, eight earthquakes of magnitude 2.3–2.9 occurred in a region where no earthquakes had previously been recorded. During the next three weeks, more than 800 microearthquakes were located (and many more detected), most at a depth of 25–31 km and within a radius of about 5 km. After about two months, almost all activity ceased. The clear P- and S-wave arrivals …
Structural Evolution Of A Composite Middle To Lower Crustal Section: The Sierra De Pie De Palo, Northwest Argentina, Sean R. Mulcahy, S. M. Roeske, W. C. Mcclelland, F. Jourdan, A. Iriondo, P. R. Renne, J. D. Vervoort, G. I. Vujovich
Structural Evolution Of A Composite Middle To Lower Crustal Section: The Sierra De Pie De Palo, Northwest Argentina, Sean R. Mulcahy, S. M. Roeske, W. C. Mcclelland, F. Jourdan, A. Iriondo, P. R. Renne, J. D. Vervoort, G. I. Vujovich
Geology Faculty Publications
The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect reveals that the Sierra de Pie de Palo preserves a middle to lower crustal ductile thrust complex consisting of individual structural units and not an intact ophiolite and cover sequence. Top-to-the-west thrusting occurred intermittently on discrete ductile shear zones from ∼515 to ∼417 Ma and generally propagated toward the foreland with progressive deformation. Ordovician crustal shortening and …
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Geology Faculty Publications
The objective of this encyclopedia is to present the current state of scientific understanding of various aspects of earth’s cryosphere – snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost – and their related interdisciplinary connections under one umbrella. Therefore, every effort has been made to provide a comprehensive coverage of cryosphere by including a broad array of topics, such as the atmospheric processes responsible for snow formation; snowfall observations; snow cover and snow surveys; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide …
Timing, Distribution, Amount, And Style Of Cenozoic Extension In The Northern Great Basin, Christopher D. Henry, Allen J. Mcgrew, Joseph P. Colgan, Arthur W. Snoke, Matthew E. Brueseke
Timing, Distribution, Amount, And Style Of Cenozoic Extension In The Northern Great Basin, Christopher D. Henry, Allen J. Mcgrew, Joseph P. Colgan, Arthur W. Snoke, Matthew E. Brueseke
Geology Faculty Publications
This field trip examines contrasting lines of evidence bearing on the timing and structural style of Cenozoic (and perhaps late Mesozoic) extensional deformation in northeastern Nevada. Studies of metamorphic core complexes in this region report extension beginning in the early Cenozoic or even Late Cretaceous, peaking in the Eocene and Oligocene, and being largely over before the onset of “modern” Basin and Range extension in the middle Miocene. In contrast, studies based on low- temperature thermochronology and geologic mapping of Eocene and Miocene volcanic and sedimentary deposits report only minor, localized extension in the Eocene, no extension at all in …
Communications And 'Forestructures' At The Geological Intersection Of Caves And Subsurface Water Flow: Hermeneutics And Parochialism, Lee J. Florea, H. L. Vacher
Communications And 'Forestructures' At The Geological Intersection Of Caves And Subsurface Water Flow: Hermeneutics And Parochialism, Lee J. Florea, H. L. Vacher
Geology Faculty Publications
The direction of cave and karst science throughout its history has been partly determined by communication—or, more commonly, the lack of communication—between non-scientist cavers and non-caving physical geologists writing about karst. Within each community, advancement of ‘cave awareness’ occurred through a hermeneutic circle in which ‘forestructures’ guided progress. One result was regionalism of speleo-genetic theories developed within karst science because of the weight of evidence placed upon local or regional observations. Many speleogenetic theories of the mid-1900s suffer from this parochialism, failing to take into account findings from karst of different geologic settings. During the past half-century, the accumulated worldwide …