RIO GRANDE RIFT

An Aeromagnetic and Geologic Study

PRJ has completed an aeromagnetic and geologic compilation and analysis of the Rio Grande rift in Colorado and New Mexico. Gold deposits, such as are present at Ortiz, Carache Canyon, and San Luis, have stimulated renewed interest in the region. The analysis was undertaken to relate magnetics and structure to potential Tertiary gold mineralization which may be associated with the Rio Grande rift.

Published compilations of aeromagnetic surveys in the public domain have lost much of the detail that is present in the original data. To improve upon this, PRJ obtained original digital and analog data for reprocessing. Over 60 surveys were regridded and mosaics were prepared. IGRF and level corrections were applied and downward continued to a draped surface 1,000 feet above the ground. Preliminary data were then remapped at a scale of 1:250,000 and merged. The final integrated magnetic data set is a substantial improvement over any of the publicly available regional aeromagnetic maps. The improvement is the result of PRJ applying a differential continuation to a lower-draped surface, which has allowed us to preserve most of the original survey detail.

DELIVERABLES

• Compiled aeromagnetic map
• Geology overlays
• Mineral occurrence overlays
• NURE geochem overlays
• Shadowgraphs
• Public domain Bouguer gravity overlays
• Qualitative interpretation of geophysical and geological data
• Target overlays
• Report

All maps are at a scale 1:250,000. The report discusses the general geologic and tectonic history, mineralization, results of the interpretation, and the relationship of interpreted tectonic features to potential gold mineralization. A summary of significant mining districts, a comprehensive bibliography, and a listing of aeromagnetic data sets is appended.

The Rio Grande rift study is available on a non-proprietary basis as a complete series of seven maps and respective overlays covering the entire project area.