Evidence for Sediment-Hosted Lead-Zink Deposits Indicating the Extension of the Colorado Mineral Belt, Northern DJ Basin, Colorado
EVIDENCE FOR SEDIMENT-HOSTED LEAD-ZINC DEPOSITS INDICATING THE EXTENSION OF THE COLORADO MINERAL BELT, NORTHERN DJ BASIN, COLORADO
Inks, Tanya; Rowe, Aryn; Burke, Benjamin
Modern and paleo-hydrothermal processes and their associated host rocks and mineral assemblages are well documented in pure and applied geologic literature, particularly mining related studies on ore genesis. Few studies exist on hydrothermal process in sedimentary basins beneath minable depths. Using an integrated analysis of a variety of data types, including elemental chemistry, mineralogy, 3D seismic, regional wireline logs, regional gravity data, pyrolysis, and drilling parameters, this study interprets a hydrothermally-emplaced ore body at depth in the Cretaceous Codell sandstone in the northern DJ Basin of Colorado.
This study interprets a sandstone-hosted Pb-Zn ore body based on mineral and elemental concentrations measured from X-ray diffraction and X-Ray fluorescence spectroscopy. This interpreted deposit has many similarities with Mississippi Valley-Type Pb-Zn deposits described in literature. Seismic pre-stack simultaneous elastic inversion mapping indicates seismic density anomalies occur concurrently with anomalous drilling rates and anomalously high metal and mineral concentrations seen in XRD and XRF analyses. The sediment-hosted ore deposit represents an identifiable drilling hazard. Seismic also shows a close relationship between shallower faulting and an interpreted regional basement lineament that appears to be related to the northern extension of the Colorado Mineral Belt. The Colorado Mineral Belt coincides with a region of low seismic velocities in the mantle, and a corresponding area that has a negative Bouguer gravity anomaly. This study suggests that this trend continues further to the north of the Wattenberg Field as indicated by the continuation of the low Bouguer gravity anomaly under the
Hereford field. The interpreted presence of the sediment-hosted ore body in the Codell raises basic petroleum system questions around the timing of the ore body emplacement and the associated source rock maturity that may or may not have developed via the hydrothermal system.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019