Upcoming Events
16 Apr (GEOL) Robert Raynolds, Denver Basin Geology
Apr 16, 2026, 4:30 - 5:30 PM
Speaker: Bob Raynolds, Consulting Geologist
Time: Thu, 16 Apr, 4:30pm ET
Location: Exploratory 1309 and via Zoom (for link, email lhinnov@gmu.edu)
Title: Evolution of the Laramide Denver Basin and Drilling of the Kiowa Core
Abstract: The Laramide Denver Basin is an asymmetric foreland basin established during the Late Cretaceous Laramide Orogeny at the foot of the growing Front Range in Colorado.
The mountain building activity tied to the development of the basement cored Front Range Uplift provided sediment supply to the foreland basin where subsidence was enhanced by sediment loading. Deposition of synorogenic sediments started at about 67.4 Ma and continued until about 63.5 Ma when a multi-million year hiatus in sedimentation occurred.
Sediment accumulation started again at about 58 Ma and persisted for an unknown time interval. These two pulses of sediment are bounded by unconformities and have been termed the D1 and D2 Sequences. The earlier sequence, the D1, encompasses the K/Pg boundary. In 1999, these strata were sampled by the Kiowa core. This 2256 foot core was drilled by the Denver Museum of Nature & Science with NSF support. The unslabbed core is stored at the US Geological Survey's Core Research Center in Lakewood, Colorado. The core was spud in Quaternary alluvium, cored a portion of the upper D2 Sequence, cored the Denver Basin Paleosol and the entirety of the D1 Sequence, the Laramie Formation, the Fox Hills Sandstone and the uppermost marine Pierre Shale, thus obtaining a complete core from the sagebrush to the sea.
Bio: Robert G. Raynolds is a consulting geologist from Longmont, Colorado. He received a BA from Dartmouth College, an MA from Stanford University, and returned to Dartmouth College for a PhD with a dissertation on sedimentation in the Himalayan Foothills, Pakistan. He has conducted field work in North, South and Central America, Africa and Asia, He is a research associate at the Denver Museum of Nature and Science and and adjunct faculty member at the Colorado School of Mines. He is president of the Colorado Scientific Society and a past officer of Dinosaur Ridge, and manages websites on the geology of Colorado, northern Kenya and Pakistan.
