New Mexico Geological Society Annual Spring Meeting — Abstracts

The Lower Permian (Leonardian) Veso Formation in New Mexico consists of up to 300 m of interbedded eolian, sabkha, lagoonal, and shallow-marine siliciclastic and carbonate rocks arranged into transgressive and overlying regressive successions. Environments change from predominantly eolian in the north to more mixed marine and eolian throughout the remainder of the state. Lagoonal gypsum beds become increasingly common in the east-central part of the state. A middle Limestone Member is present throughout most of the state, and marks the time of maximum transgression. The overlying Glorieta Formation consists of up to 60 m of marine and eolian quartzose sandstone representing the onset of another transgressive event. The Glorieta is no longer a recognizable map unit in the southern part of the state. Much of the Yeso and Glorieta Formations are arranged into 2 to10 m-thick parasequences composed of mixed marine and nonmarine sediments. In the Veso Formation, eolian beds are characterized by orange, very fine-grained sandstones that display climbing wind ripples deposited either on a sand sheet or on the landward side of a coastal salina. Intertidal and supratidal dolomites are characterized by fenestral fabric, desiccation cracks, and stromatolites, although some dolomites lack these features and may be lagoonal in origin. Gypsum beds consist of cm-scale white and grey or black laminae, and were deposited in hypersaline lagoons, whereas normal-marine conditions are represented by fossiliferous limestones. The Glorieta Formation is characterized by white fine-grained quartzose sands. Sedimentary features are often obscured but the formation contains eolian climbing ripples, with marine conditions indicated by wave oscillation ripples, planar bedding, and trough crossbeds. The large number of parasequences suggest relative sea-level changes on the order of 10⁴ to 10⁵ years.