Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Publication
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
The Unusual 3d Interplay Of Basement Fault Reactivation And Fault-Propagation-Fold Development: A Case Study Of The Laramide-Age Stillwell Anticline, West Texas (Usa), Benjamin Surpless, Nicola Hill, Cara Beasley
The Unusual 3d Interplay Of Basement Fault Reactivation And Fault-Propagation-Fold Development: A Case Study Of The Laramide-Age Stillwell Anticline, West Texas (Usa), Benjamin Surpless, Nicola Hill, Cara Beasley
Benjamin E Surpless
Subsurface fault geometries have a systematic influence on folds formed above those faults. We use the extraordinarily well-exposed fold geometries of the Laramide-age Stillwell anticline in west Texas (USA) to develop a strain-predictive model of fault-propagation fold formation. The anticline is a 10-km long, NW-trending, NE-vergent, asymmetric fold system with an axis that displays a map-view left-stepping, en echelon pattern. We integrated field observations, geologic and structural data, cross-sections, and 2D kinematic modeling to establish an unusual 3D two-stage model of contractional fold formation, including: 1) reverse reactivation of a pre-existing, NW-striking, SW-dipping, left-stepping, en echelon normal fault system in …
(U-Th)/He Chronologic Constraints On Secondary Fe-Oxide Mineralization In Southwestern New Mexico, Mike Channer, Alexis Ault
(U-Th)/He Chronologic Constraints On Secondary Fe-Oxide Mineralization In Southwestern New Mexico, Mike Channer, Alexis Ault
Mike Channer
Temporal constraints on fluid flow, mineralization, and brittle deformation are important for understanding a variety of upper-crustal processes. However, limited radioisotopic methods exist to directly date these processes. Hematite commonly co-precipitates with economically valuable mineral phases in hydrothermal ore deposits, such as copper, uranium, gold, and other rare-earth elements, and occurs in fracture systems and faults. Hematite is amenable to (U-Th)/He dating, and we will apply this method to two case studies in the Rio Grande rift, New Mexico. First, a suite of millimeter-thick hematite- and turgite-coated fracture surfaces cross-cut an ~54-60 Ma porphyritic rhyolite near Lordsburg in southwest New …
U-Pb Zircon Constraints On The Age And Provenance Of The Rocas Verdes Basin Fill, Tierra Del Fuego, Argentina, David Barbeau, David Gombosi, Khandaker Zahid, Michael Bizimis, Nicholas Swanson-Hysell, Victor Valencia, George Gehrels
U-Pb Zircon Constraints On The Age And Provenance Of The Rocas Verdes Basin Fill, Tierra Del Fuego, Argentina, David Barbeau, David Gombosi, Khandaker Zahid, Michael Bizimis, Nicholas Swanson-Hysell, Victor Valencia, George Gehrels
David L Barbeau Jr
The Late Jurassic to Early Cretaceous Rocas Verdes basin constitutes one of the most poorly understood components of the southernmost Andes. As a result, accurate reconstructions and interpretations of deformation associated with the Andean orogeny and the kinematics of Scotia arc development also remain poorly constrained. In this data brief, we report U-Pb zircon ages from sandstones of the Rocas Verdes basin fill and from a crosscutting pluton in the southernmost Andes of Argentine Tierra del Fuego. Detrital samples contain predominant Early to early Middle Cretaceous (circa 130–105 Ma) U-Pb zircon age populations, with very small or single-grain middle Mesozoic …
Cooling History Of Atlantis Bank Oceanic Core Complex: Evidence For Hydrothermal Activity 2.6 Ma Off Axis, J. J. Schwartz, Barbara John, Michael Cheadle, P. W. Reiners, A. G. Baines
Cooling History Of Atlantis Bank Oceanic Core Complex: Evidence For Hydrothermal Activity 2.6 Ma Off Axis, J. J. Schwartz, Barbara John, Michael Cheadle, P. W. Reiners, A. G. Baines
Michael Cheadle
We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (< 1 Ma), yielding cooling rates > 1200 degrees C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and …
Cooling History Of Atlantis Bank Oceanic Core Complex: Evidence For Hydrothermal Activity 2.6 Ma Off Axis, J. J. Schwartz, Barbara John, Michael Cheadle, P. W. Reiners, A. G. Baines
Cooling History Of Atlantis Bank Oceanic Core Complex: Evidence For Hydrothermal Activity 2.6 Ma Off Axis, J. J. Schwartz, Barbara John, Michael Cheadle, P. W. Reiners, A. G. Baines
Barbara John
We report 26 (U-Th)/He zircon ages from Atlantis Bank, Southwest Indian Ridge, which constrain time scales and rates of lower crustal cooling in ultraslow spreading oceanic crust in this setting. Samples from the detachment fault surface indicate that denuded oceanic crust cooled rapidly (< 1 Ma), yielding cooling rates > 1200 degrees C/Ma, consistent with existing models for the cooling of oceanic crust. (U-Th)/He zircon ages from samples collected along N-S and E-W trending faults scarps record young ages inconsistent with standard cooling models for lower oceanic crust. These samples have a mean (U-Th)/He zircon age 2.6 Ma younger than their corresponding igneous crystallization ages and …