LOWER PERMIAN STRATA AND DEPOSITIONAL CYCLES IN THE LUCERO UPLIFT, CENTRAL NEW MEXICO

Lower Permian strata exposed in the Lucero uplift of Valencia County, central New Mexico, are a succession of nonmarine and marine sedimentary rocks ~660 m thick that are assigned to the (in ascending order) Abo, Yeso, Glorieta and San Andres formations. The Abo Formation disconformably overlies the upper Virgilian Red Tanks Member of the Bursum Formation and is ~150 m thick, consisting of red-bed mudstone, arkosic sandstone and siltstone. The Yeso Formation conformably overlies the Abo Formation and is ~348 m thick. It can be divided into the lower, Meseta Blanca (~70 m thick) and overlying Los Vallos (~278 m thick) members. The Meseta Blanca Member is quartz-rich sandstone in beds that are trough crossbedded or display climbing ripple laminations. The Los Vallos Member is mostly very fine-grained sandstone, siltstone and gypsum with some thin but persistent beds of dolomite/limestone. The Glorieta Sandstone disconformably overlies the Yeso Formation, is ~53 m thick and consists of quartzose sandstone and a single, 7-m-thick bed of gypsum. It is conformably overlain by the San Andres Formation, which is ~109 m thick and mostly gypsum with lesser amounts of limestone, sandstone and shale. In the Lucero uplift, the Middle Triassic Moenkopi Formation rests disconformably on the San Andres Formation. Permian rocks in the Lucero uplift represent the transition from fluvial depositional conditions (Abo Formation) through eolian and tidal flat (Yeso Formation) to shoreface (Glorieta Sandstone) and finally to shallow marine (San Andres Formation) conditions. While there is depositional cyclicity evident in the Yeso, Glorieta and San Andres formations, the cycles in the Lucero uplift section cannot be directly correlated to sea-level cycles documented in West Texas. This suggests that regional tectonic or subsidence-related processes affected deposition of the Leonardian sediments in central New Mexico.