New Mexico Geology Studies Stratigraphy

by Rachel Armstrong

SOCORRO, N.M., February 3, 2003 - The latest issue of New Mexico Geology focuses on the stratigraphy of the Tanos and Blackshare Formations, two newly defined lithostratigraphic units in the Hagan embayment along the Rio Grande rift. The formations comprise over a kilometer of sedimentary and volcanic rocks.

The Tanos Formation is 279 meters, or 915 feet thick, whereas the overlying Blackshare Formation is over 1,000 meters, or 3,281 feet thick. The article states that the relationship between the formations indicates that they are a derivation from the nearby Ortiz Mountains in Santa Fe County.

Another article presents the study of fossilized marine fauna in the Bar B Formation of the Derry Hills, New Mexico. The fauna contains mainly three mollusk species, suggesting that it lived in a deep, quiet marine environment on organic-rich, poorly oxygenated muddy substrate.

The periodical also features abstracts from talks given at the 23rd Annual New Mexico Mineral Symposium in November 2002. Geologists from across the country discussed their mineralogical findings, such as the recovery of a 17-ton copper boulder in Lake Superior, and the microchemical investigation of the colors of smithsonite, examples of which grace the cover of this issue of New Mexico Geology.

New Mexico Geology is published quarterly by New Mexico Bureau of Geology and Mineral Resources (NMBGMR), a service division of New Mexico Tech. A subscription to the award-winning journal costs $12 per year, or $22 for two years. Individual issues may be purchased for $3.50 each. For more information about New Mexico Geology, or any other NMBGMR publication, write to the Bureau Publication Office, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801, call (505) 835-5410, or visit the Bureau's website at http://geoinfo.nmt.edu.