Geological Insights & Event News

The August 2016 FCGS newsletter highlights the annual summer picnic and announces fall talks by Marsha W. French, Cat Campbell, Steve Cossey, and Ian Walton. Election results name Rebecca Helms as President, with new and returning officers for both the Society and Foundation. Regional field trip opportunities include the Colorado Groundwater Association’s Manitou Springs Mineral Waters trip and AEG RMS’s Colorado Springs Landslides and Debris Flow Hazards tour.

Dr. Katherine Potter presents results from the 1912 m Kimama core, showing continuous mafic volcanism on the central Snake River Plain for 6.4 Ma, with basalt, loess, and fluvial sands recording steady accumulation and variable magma sources . In his Prez Sez column, President John Youle outlines 2016 goals: a spring field trip in the San Juan Basin, a new FLC research mapping feature, and launching Oil and Gas Fields of the Four Corners, Vol. IV . Regional news includes upcoming meetings, workshops, and the June Tocito, El Vado & Gallup Sands field trip led by Dr. Leslie Wood.

Jonathan Moore describes the history and geology of Creede’s mining district. Epithermal veins, first prospected in 1876, led to major discoveries including Nicholas Creede’s Holy Moses claim, sparking an 1890 boom and over a century of Ag Pb Zn production. Mineralization formed along graben faults within the Bachelor caldera, producing rich low sulfide veins of quartz, barite, and rhodochrosite. In his Prez Sez column, President John Youle reflects on scientific progress through “biffing it,” urging members to embrace hard falls as part of good science.

Jonathan Harvey’s abstract examines how the Main Himalayan Thrust shapes seismicity and rapid uplift in the central Himalaya. New data from western Nepal reveal a major crustal discontinuity that splits the steep topography belt, altering seismic hazard patterns and informing context for the April 2015 M7.8 Gorkha earthquake. In Prez Sez, President John Youle highlights the Society’s strength in member dedication. We mourn the loss of Dr. Frank Bowman, who founded the geology department at FLC. The Foundation published a financial report. The FCGS horseshoe tournament was won by Chip Head.

FLC seniors presented their research to the Society. J. Girts models Silverton–San Juan caldera faults, revealing hidden structures and radial–concentric patterns tied to dome growth and collapse. C. Passehl’s OSL work suggests Durango glacial stratigraphy needs revision. S. Holden shows La Plata mineralization occurred in two pulses at ~57 Ma and ~27 Ma. J. Adams finds McElmo CO₂ reflects mixed crustal–mantle sources. In Prez Sez, President Paul Spear urges returning to basics in unconventional petrophysics and preparing for the next drilling boom. We regret the passing of Rob Blair.

Christine Smith Siddoway presents new U Pb detrital zircon data showing that the Tava sandstone dikes of the Colorado Front Range derive from Neoproterozoic (770–680 Ma) Rodinia strata, with DZ peaks matching Grenville and Colorado sources. The work constrains emplacement to Pennsylvanian or earlier and links the dikes to early movement on the ancestral Ute Pass fault. In his Prez Sez column, President Paul Spear describes Mancos concretions and thanks John Youle. Regional news includes the upcoming San Juan College Energy Conference and a part time Petroleum Geology teaching opportunity.