After a string of igneous rocks it’s time to mix things up a bit and go sedimentary on you for a change. Today’s featured deskcrop is a fossiliferous limestone that I collected at the base of the Mississippian Muleshoe Mound in the Sacramento Mountains near Alamagordo, New Mexico during a spring break field trip led by University of Wisconsin carbonate sedimentologists Lloyd Pray and Toni Simo during my first year as a grad student at UW-Madison. I’m invoking the Dunham classification scheme to label this a “fossiliferous packstone” but I’d be glad to be corrected if any of my more sedimetarily inclined colleagues sees fit to do so. I can tell you that the most prominent fossils in this sample are the cyllindrical crinoid stems that appear throughout the muddy matrix of this rock.
Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!