Welcome Guest [Log In] [Register]
Speculative biology is simultaneously a science and form of art in which one speculates on the possibilities of life and evolution. What could the world look like if dinosaurs had never gone extinct? What could alien lifeforms look like? What kinds of plants and animals might exist in the far future? These questions and more are tackled by speculative biologists, and the Speculative Evolution welcomes all relevant ideas, inquiries, and world-building projects alike. With a member base comprising users from across the world, our community is the largest and longest-running place of gathering for speculative biologists on the web.

While unregistered users are able to browse the forum on a basic level, registering an account provides additional forum access not visible to guests as well as the ability to join in discussions and contribute yourself! Registration is fast, free, and instantaneous.

Join our community today!

Username:   Password:
Add Reply
Cretaceous glaciations
Topic Started: Feb 23 2012, 03:29 PM (1,061 Views)
JohnFaa
Member Avatar
Adveho in mihi Lucifer
 *  *  *  *  *  *  *  *  *  *  *
Quote:
 
There is indirect evidence that a glaciation event existed during the late Aptian-early Cenomanian [approximately 100 MA]. Here in eastern Nebraska the event is recorded by a large-scale, unconformity-bounded sequence of the lower Woodbury Member of the Dakota Sandstone [aka "Muddy-Mowry Seaway" or "Muddy sandstone"]. An eustatic sea-level mechanism lowered worldwide sea-levels by more than 25 m and that this sea-level fall occurred in a rather short period of geologic time. A glacioeustatic component is most likely to account for the observed sea-level changes during the mid-Cretaceous “greenhouse” world. I'm not aware of the existence of large-scale continental ice sheets. But, a Southern Hemisphere polar ice sheet with limited extent and volume compared to “icehouse” continental ice sheets, and global alpine glaciers that were fed by wet climate cycles [a local condition which is well documented during Dakota sedimentation] could account for sea-level fluctuations that resulted in valley incision and subsequent filling.

references:

Alley, N.F., and Frakes, L.A. 2003. First known Cretaceous Glaciation: Livingston Tillite Member of the Cadna-owie Formation, South Australia. Australian Journal of Earth Science. v. 50, p. 139-144.

Bornemann, Norris, Friedrich, Beckmann, Schouten, Sinninghe Damsté, Vogel, Hofmann and Wagner.2008. "Isotopic Evidence for Glaciation During the Cretaceous Supergreenhouse" Science Vol. 319 no. 5860 pp. 189-192

Gale, A.S., Hardenbol, J., Hathaway, B., Kennedy, W.J., Young, J.R., and Phansalker, V. 2002. Global correlation of Cenomanian (Upper Cretaceous) sequences: Evidence for Milankovitch control on sea level. Geology. v. 30, p. 291-294.

Haq, B.U., Hardenbol, J., and Vail, P.R. 1987. Chronology of Fluctuating Sea Levels since the Triassic. Science. V. 235, n. 4793, p. 1156-1167.

Immenhauser, A. 2005. High-rate sea-level change during the Mesozoic: New approaches to an old problem. Sedimentary Geology, Vol. 175, p. 277-296.

Ludvigson, G.A., Gonzalez, L.A., Metzger, R.A., Witzke, B.J., Brenner, R.L., Murillo, A.P., White, T.S. 1998. Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology. Geology, v. 26, n. 11, p. 1039-1042.

Miller, K.G., Sugarman, P.J., Browning, J.B., Kominz, M.A., Hernandez, J.C., Olsson, R.K., Wright, J.D., Feigenson, M.D., and Van Sickel, W. 2003. Late Cretaceous chronology of large, rapid sea-level changes: Glacioeustasy during the greenhouse world. Geology. v. 31, no. 7 (July), p. 585-588.

Sahagian, D., Pinous, O., Olferiev, A., and Zakharov, V. 1996. Eustatic Curve for the Middle Jurassic-Cretaceous Based on Russian Platform and Siberian Stratigraphy: Zonal Resolution. AAPG Bulletin. v. 80, no. 9. p. 1433-1458

Stoll, H.M., and Schrag, D.P. 1996. Evidence for glacial control of rapid sea-level changes in the Early Cretaceous. Science. v. 272, p. 1771-1774.
Edited by JohnFaa, Feb 23 2012, 03:31 PM.
Posted Image
Online Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Science Central · Next Topic »
Add Reply