Rockwood Quarry, San Juan Mts., Colorado (Carboniferous of the United States)

Where: La Plata County, Colorado (37.5° N, 107.14° W)

• Paleocoordinates: 16.3° S, 58.4° W (Wright 2013)

• outcrop-level geographic resolution

When: Mississippian (358.9 - 323.2 Ma)

• The Leadville Limestone at the Rockwood Quarry is 34.8m thick and has a sharp contact with the Ouray Limestone below. The top of the Leadville Limestone is an erosional surface marked by solid solution activity, terra rossa clay, large round cobbles, and boulders of limestone and chert make up the basal beds of the Molas Fm.

• bed-level stratigraphic resolution

Environment/lithology: bioturbated, dolomitic, ooidal, peloidal packstone

• The Ouray Limestone 5m below the contact is massive, brown to gray dolomite. Above that is a 2m thick bed of crinoid-bryozoan-brachiopod packstone from which the fauna was collected. Above this is a 0.6m thick bed of echinoderm-brachiopod packstone, overlain by a 1.7m thick bed of breccialike material composed of silt to boulder sized lime mudstone and wackestone. The matrix between is filled by calcite, argillaceous calcite, reddish-brown-gray iron-rich shale and shale clasts. 3.5-4m above the base of the Leadville Limestone is a 0.5-0.7m thick finegrained brownish gray dolomite with laminations 20mm-2cm thick. Birdseye structure, stromatolites, and bioturbation is common. From 4.2to 20m above the base, lime mudstone and pellet packstone with interbeds of dolomite are present. From 20-33m, the unit is composed of crossbedded massive, ooid-foraminifer-echinoderm-brachiopod packstone and grainstone. Crinoid wackestone is present from 33-35.3

Primary reference: A. K. Armstrong and B. L. Mamet. 1976. Biostratigraphy and Regional Relations of the Mississippian Leadville Limestone in the San Juan Mountains, Southwestern Colorado. United States Geological Survey Professional Paper 985:1-25 [T. Olszewski/M. Gibson/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 10240: authorized by Tom Olszewski, entered by Melissa Gibson on 15.03.2001

Creative Commons license: CC0 (CC0)

Taxonomic list

• Also collected were echinoderm debris, indet., rhynchonellid, undet., reticulariid, indet., bellerophontid gastropod, indet.
Show authors, comments, and common names
Rhynchonellata
 Rhynchonellida - Leiorhynchidae
Paurorhyncha endlichi
 Spiriferida - Cyrtospiriferidae
Cyrtospirifer whitneyi, Cyrtospirifer animasensis, Cyrtospirifer sp., Syringospira prima
Cyrtospirifer sp. Nalivkin 1924
 Orthida - Schizophoriidae
"Schizophoria australis" = Schizophoria (Schizophoria) australis
"Schizophoria australis" = Schizophoria (Schizophoria) australis Kindle 1909
Strophomenata
 Orthotetida - Schuchertellidae
Schuchertella coloradoensis
 Productida - Productidae
Leioproductus coloradoensis