11: Roadside faults, folds, fossils, crystals, and diamond pipes—Sampling the geologic diversity of northern Colorado
Barbara EchoHawk, Uwe Kackstaetter, 2016. "Roadside faults, folds, fossils, crystals, and diamond pipes—Sampling the geologic diversity of northern Colorado", Unfolding the Geology of the West, Stephen M. Keller, Matthew L. Morgan
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Enjoying geology does not necessarily mean strenuous hikes. This day-long, easygoing field trip is literally out of a car with various stops along the northern Colorado Front Range from north of Boulder to the Wyoming state line, with the longest hike being ~1.6 km (1 mi) round trip. We will examine and discuss stratigraphic units and geologic features from the Precambrian to the Quaternary, including the Great Unconformity. Participants will see inclined strata and differential weathering; gravel-topped mesas and inverted topography; vegetation that relies on ancient volcanic ash; evidence of the Cretaceous Seaway; a fracking simulation in the Niobrara Formation; a fault-interrupted S-shaped plunging fold trace; quarried slabs from ancient sand dunes; and impacts of the September 2013 Front Range flood. We will explore pegmatite emplacement and mineralization in the crystalline interior of the Rocky Mountains and in the Colorado Mineral Belt. Continuing north, we will see dinosaur bones in the Jurassic Morrison Formation; a mysterious snaggle-toothed rock wall; evidence of the 1976 Big Thompson flash flood; and Paleozoic strata with calcite spar, and microfossils. In conclusion, we will observe: block faulting of the northern Colorado terrain; the Virginia Dale ring dike and its famous magma mixing outcrop; and a deeply weathered, freely accessible diamond pipe recently discovered by Metropolitan State University of Denver students and faculty. This trip is excellent for anyone who would like to sample the amazing diversity of northern Colorado’s geology, including scientists, students, educators, and rock hounds with opportunities to collect some nice specimens for teaching or personal enjoyment.
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Prepared in conjunction with the 2016 GSA Annual Meeting in Denver, Colorado, this volume contains sixteen guides to field trips in this rich geologic region. The four “Great Surveys” of the late 1800s ventured west to explore and document the region’s unknown natural resources and collect valuable geologic information. Many of the field guides in this volume, aptly titled Unfolding the Geology of the West, will cover the same hallowed ground as the early geologic expeditions. Organized into four sections, this volume spans some of the major subdisciplines of geology: (1) stratigraphy, sedimentology, and paleontology; (2) structure and metamorphism; (3) Quaternary landscape evolution; and (4) engineering and environmental geology.