Northern Branch, The University of New Mexico, Los Alamos, New Mexico 87544]
Crinoids, hardgrounds, and community succession: The Silurian Laurel—Waldron contact in southern Indiana
Article first published online: 9 OCT 2007
Volume 6, Issue 3, pages 239–251, July 1973
How to Cite
HALLECK, M. S. (1973), Crinoids, hardgrounds, and community succession: The Silurian Laurel—Waldron contact in southern Indiana. Lethaia, 6: 239–251. doi: 10.1111/j.1502-3931.1973.tb01197.x
- Issue published online: 9 OCT 2007
- Article first published online: 9 OCT 2007
Halleck, Margaret S.: Crinoids, hardgrounds, and community succession: The Silurian Laurel-Waldron contact in southern Indiana.
The uppermost surface of the Silurian Laurel Limestone at its contact with the Waldron Shale in southeastern Indiana was a hardground lithified prior to the deposition of the Waldron. Evidence for this conclusion is the presence of attached palmate crinoid roots, auloporid corals, and craniid brachiopods on the Laurel surface; the irregularity of the contact with the Waldron; and a pyritic veneer at this contact. The hardground apparently had a submarine origin. In addition to the attached epifauna mentioned above, algal-sediment ‘clods’ formed on this surface. Some of these accumulated around the crinoid stems, causing them to produce cirral extensions. The resulting community was a crinoid ‘meadow’ with algal growths forming sediment traps around and between the crinoids. Later stages of Waldron Shale deposition led to the development of a soft-bottom community.