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Full-Text Articles in Physical Sciences and Mathematics

Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley Hacker, William Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Ann Blythe, William Mcclelland Jul 2010

Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley Hacker, William Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Ann Blythe, William Mcclelland

Ann Blythe

Structural, thermobarometric, and thermochronologic investigations of the Kangmar Dome, southern Tibet, suggest that both extensional and contractional deformational histories are preserved within the dome. The dome is cored by an orthogneiss which is mantled by staurolite + kyanite zone metasedimentary rocks; metamorphic grade dies out up section and is defined by a series of concentric kyanite-in, staurolite-in, garnet-in, and chloritoid-in isograds. Three major deformational events, two older penetrative events and a younger doming event, are preserved. The oldest event, D1, resulted in approximately E-W trending tight to isoclinal folds of bedding with an associated moderately to steeply north dipping axial …


Deformation Of Continental Crust Along A Transform Boundary, Coast Mountains, British Columbia, Scott Bogue, Margaret Rusmore, Karen Dodson, Kenneth Farley, Glenn Woodsworth Dec 2009

Deformation Of Continental Crust Along A Transform Boundary, Coast Mountains, British Columbia, Scott Bogue, Margaret Rusmore, Karen Dodson, Kenneth Farley, Glenn Woodsworth

Scott Bogue

New structural, paleomagnetic, and apatite (U-Th)/He results from the continental margin inboard of the Queen Charlotte fault (∼54°N) delineate patterns of brittle faulting linked to transform development since ∼50 Ma. In the core of the orogen, ∼250 km from the transform, north striking, dip-slip brittle faults and vertical axis rotation of large crustal domains occurred after ∼50 Ma and before intrusion of mafic dikes at 20 Ma. By 20 Ma, dextral faulting was active in the core of the orogen, but extension had migrated toward the transform, continuing there until <9 Ma. Local tilting in the core of the orogen …


Faculty Spotlight: Mark Sutherland, Mark Sutherland Dec 2009

Faculty Spotlight: Mark Sutherland, Mark Sutherland

Mark Sutherland

Interview with Mark J. Sutherland about his earth science teaching career at College of DuPage.


Very Rapid Geomagnetic Field Change Recorded By The Partial Remagnetization Of A Lava Flow, Scott Bogue, Jonathan Glen Dec 2009

Very Rapid Geomagnetic Field Change Recorded By The Partial Remagnetization Of A Lava Flow, Scott Bogue, Jonathan Glen

Scott Bogue

A new paleomagnetic result from a lava flow with a distinctive, two-part remanence reinforces the controversial hypothesis that geomagnetic change during a polarity reversal can be much faster than normal. The 3.9-m-thick lava (“Flow 20”) is exposed in the Sheep Creek Range (north central Nevada) and was erupted during a reverse-to-normal (R-N) geomagnetic polarity switch at 15.6 Ma. Flow 20 began to acquire a primary thermoremanence while the field was pointing east and down but was soon buried, reheated, and partially-remagnetized in a north-down direction by the 8.2-m-thick flow that succeeded it. A simple conductive cooling calculation shows that the …