The West Texas nexus: Orogeny, magmatism, K-Pg boundary, vertebrate biostratigraphy, and Chihuahuan Desert geohydrology
Bibliographic record
Abstract
ABSTRACT Rocks and geologic structures exposed at the surface in the Big Bend region of far west Texas, USA, preserve evidence of three significant North American plate-tectonic events: The late Paleozoic Marathon-Ouachita orogeny, the late Cretaceous–Paleogene Laramide orogeny, and the Neogene–present extensional event of Rio Grande rifting. Rocks here also preserve a 30-million-year span of magmatism that temporally straddles both the end of the early Cenozoic contraction event and the beginning of the more recent extension, and, therefore, record that transition. Modern terrestrial waters also contribute to the geology of this arid region, both with the Rio Grande’s incision exposing some of these rocks and with their hosting of groundwater and springs. Visits to sites during this four-day field trip in and around Big Bend Ranch State Park and Big Bend National Park will increase understanding of these geologic events. DEDICATION This field trip is dedicated to the memory of Blaine Hall, an exceptional friend and colleague to many of this field guide’s authors and an enthusiast of Big Bend geology. Blaine completed his B.S. in geology at University of Texas (UT)–El Paso, received his M.Sc. in geological oceanography from Dalhousie University, and carried out research in marine geology and geophysics while at Lamont-Doherty Earth Observatory of Columbia University. His industry experience began with Superior Oil in minerals exploration for Proterozoic placer gold and kimberlites in the Rockies, Canada, Kansas, and Arkansas. He then shifted to petroleum, beginning with studies of heavy oil reservoirs in California for Mobil Oil and continuing with exploration and production projects in Argentina and southern South America. Blaine returned to his native West Texas and spent the next ten years teaching geology and mathematics at Sul Ross State University. While there he was also active with the Chihuahuan Desert Research Institute, where he developed a permanent exhibit on the geology of the Davis Mountains and presented educational workshops. He joined Texas Parks and Wildlife in 2010 as an interpretive ranger at Big Bend Ranch State Park, and he helped direct research of master’s students from Sul Ross State University and collaborated with faculty from UT-Austin on early Paleozoic sedimentation and tectonics in the Solitario dome (see Fig. 0.1). Contents Introduction Tectonic Maps of the Big Bend Region Showing Cordilleran and Rio Grande Rift Structures Road Log Day 1: Big Bend Ranch State Park Day 2: West Side of Big Bend National Park Day 3: East Side of Big Bend National Park Day 4: Marathon to San Antonio Acknowledgments References Cited
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.006 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".