Virtual Field Trip—Group 5
Geologic Overview of Pennsylvanian Holder Formation Cycles
We are a research and service division of:
Clockwise from top left: Nicole Erdelyi, Crystal Cobble,
Dusti Griffin,
Azza Ezzat,
Robert Tcherneshoff,
Ronda Gillespie, and
Ken Stanley.
Late Pennsylvanian Holder Formation with Wilson-type cycles in the La Luz anticline in the Sacramento Mountains of New Mexico.
Background
Information for the
Pennsylvanian Holder Formation Cycles
Virgillian-age cycles in the Holder Formation are located at the mouth of the Laborcita Canyon in the Sacrament Mountains. The outcrop was once located on an ocean shelf during the Late Pennsylvanian age.
In the Holder Formation, sediments were deposited at that time on an open marine shelf. Limestone was deposited during a time of high sea level. During a low sea level, shale, sandstone, and conglomerate were present. Sea level changes could be due to glaciation or the movement of tectonic plates. Within the limestone, normal marine fossils include fusulinids, crinoids, brachiopods, phylloid algae, gastropods, mollusks, corals, and bryozoans.
