Rocky Mountain Section - 64th Annual Meeting (9–11 May 2012)

Paper No. 40
Presentation Time: 8:00 AM-5:30 PM

INVESTIGATION OF THE INTERMEDIATE SYSTEMATICS OF FOSSIL INSECTS COLLECTED AT THE CLARE QUARRY SITE IN THE FLORISSANT FOSSIL BEDS FROM 1996 - PRESENT


CANCELLARE, Joseph A., Department of Geological Sciences, El Paso Community College, El Paso, TX 79925 and LEMONE, David, Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968, stonefly.1@live.com

The Clare Quarry is a proprietary Quarry located in the town of Florissant, Teller County, Colorado, approximately 30 miles west of Colorado Springs on land proximal to the Florissant Fossil Beds National Monument. The elevation at the quarry face is 2500 meters ASL. 40Ar/39 dating of the upper beds of the Florissant Formation indicates an age of 34.07 +/- 0.10 Ma.

An Oreodont fossil jaw and other mammalian fossils place the formation in the Chadronian Age. The basin in which the formation lies is undergirded by Wall Mountain Tuff dated at 37Ma, which sits on Pike’s Peak Granite, which is dated at1080 Ma. In the Late Eocene the Florissant region was lacusterine in nature due to the intermittent damming of the river valley which runs north into Florissant. The ash and lahars from volcanic eruptions in the Thirty-nine Mile Volcano Field formed impoundments that produced shallow lakes for what is thought to have been a period of 5000 years. Repeated ash falls placed plant matter and insect material in the lakes and streams that were formed intermittently during the period. The ash layers in the Florissant Formation are very fine grained, and contain diatomaceous mats that formed on the lake deposited ash layers aiding in the preservation of plant and insect material.

Early work on Florissant Fossils was done by Lesquereaux (plants) 1878, Scudder (insects) 1890, and Mac Ginitie (plants) 1953. This project began 17 years ago and has consisted of collection trips ranging from one to eight days during the summer months. The collection consists of 2400 catalogued plants, insects, and fish fossils. To date classification is superficial. One of the early objectives of this work was to collect series of the same genera however there is no discernible pattern below the ordinal level due to the random nature of fossil preservation. In this phase the primary objective will be to place as many insect specimens into families as possible. Many insect families (but no genera) found in the Florissant persist in life today.

Handouts
  • EPCC GSA poster.pdf (4.6 MB)