Pennsylvanian-Permian Climatic Records From Low Latitude Rainsville Trough in Northern New Mexico
Abstract
Stratigraphic records of chemical sedimentation as well as clastic influx in a basin archives
paleoclimatic data of that region. Formation of coals are indicative of continually recurring wet
climates whereas deposition of chemical rocks i.e., evaporites and/or carbonates are linked to
document dry climates. Thus, stratigraphic records of climate-sensitive sediments provide
valuable clues to asses paleoclimatic information of that region. The repetitive occurrences of
coals versus evaporites in the subsurface Rainsville trough are utilized to reconstruct late
Paleozoic paleoclimate.
Taos-Rainsville trough, also known as the Rowe-Mora basin is one of the ancestral Rocky
Mountain (ARM) basins located near low latitude during the Pennsylvanian-Permian. Within the
Rainsville trough late Paleozoic sediments are mostly in subsurface. Therefore, available
petrophysical well log data were used for lithologic interpretation. In addition, developed Matlab
codes were used to identify coals and evaporites, and correlate them between wells. Significant
repetitive coal beds occurrences along with great clastic influxes within the Sandia and Sangre de
Cristo formations indicate seasonal wet to tropical rainy climatic condition prevailed during both
the Atokan and Wolfcampian time respectively. Dominants of marine carbonates associated with
evaporite are indicative of semiarid to arid conditions during deposition of the Desmoinesian
Porvenir Formation. The Leonardian Yeso Formation, containing of gypsum beds in the
Rainsville trough as well as throughout the New Mexico indicate an arid climate.
Climatic records show spatial and temporal variability during the Pennsylvanian-Permian time in
the low latitude North American continent. Traditionally late Paleozoic has been interpreted as a
wet climatic period that gradually became dryer during late Pennsylvanian through early
Permian. However, evaporite content in the Porvenir Formation and repetitive coals in the
Sangre de Cristo Formation within the Rainsville trough suggests significantly a dryer period
during the middle to late Pennsylvanian, which became relatively wetter at the time of the
Wolfcampian.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019