DH-1 Bed 7.6

From lavender beds below bed 8

DH-2 Photos

A large Arctocerid mold, the body chamber was filled with mud so it is preserved, the phragmocone was probably crushed after it left it's imprint in the soft bottom.



Jim collecting DH-2 bed 1



The DH-2 anticline looking south.
Permian red beds in the foreground, the basal Thaynes limestone on the south side of the north DH-2 fault well exposed beyond.

Something new (at least to me)

I found this while doing a little mapping this weekend. I think it is some form of Ussuriid. From the Early Triassic

See this post for update

Presentation on line

If you go to the abstract, you can now download a pdf file of the presentation I gave at the GSA meeting in Las Vegas last month.

Abstract for Presentation 12-9

4.8 Mb presentation handout download.

GSA Las Vegas

Well, Wes found out he cant give the talk at the GSA meeting in Las Vegas. The honor falls to Me!

Paper No. 12-9 11:00AM-11:20AM, March 20, 2008

A first time for everything I guess.

Clypeoceras may be Guodunites

A hint in the air of an upcoming publication in which the "Koninckites" > Clypeoceras of the Confusion Range will be assigned to the Genus Guodunites.

see this post http://ammonoidea.blogspot.com/2007/07/un-identified-ammonoids.html

Churkites vs Arctoceras

Churkites noblei Jenks 2007

The ornamentation is exactly like Arctoceras tuberculatum, the only difference is the shape of the venter. These have an acute venter, becoming almost oxyconic in large shells and Arctoceras has a well rounded venter (almost semi-circular). This could be sexual dimorphism with the round ventered forms being female and the acute ventered forms male.

Of course there are two different sizes found in the Confusion Range, the small 100-180mm and the large 300mm, perhaps these are dimorphs of Churkites and Arctoceras isnt congeneric.


Jenks, J. F., 2007, Smithian (Early Triassic) Ammonoid Biostratigraphy at Crittenden Springs, Elko County, Nevada and a New Ammonoid From the Meekoceras Gracilitatis Zone, in, Lucas S. G. and Spielmann, J. A. eds., Triassic of the American West, New Mexico Museum of Natural History and Science Bulletin 40

Opportunistic Bloom?

I am really starting to wonder if the Anasibirites Beds could preserve an opportunistic bloom. If the Prionitids (and not all the other ammonoids) began or found a way to prey on the micro gastropods of the time they may have had a great advantage and a large amount of food. Whether the beds in the Confusion Range preserve a mass mortality event or just the preservation of an unusually high amount of dead shells would need an answer.
An extinction at the base of the anasibirites beds, and a small climate gradient left the anasibirites beds to be very cosmopolitan. Perhaps they were just the most common ammonoid in the latest smithian so any unfavorable water or climatic condition would have killed only the anasibirites fauna.

Still so much to learn and figure out in all this.

Galfetti, T., H. Bucher, A. Brayard, P. A. Hochuli, H. Weissert, K. Guodun, V. Atudorei, J. Guex, 2007, Late Early Triassic climate change: Insights from carbonate carbon isotopes, sedimentary evolution and ammonoid paleobiogeography,
Palaeogeography, Palaeoclimatology, Palaeoecology 243, 394–411

Kidwell, S.M. 1991. The stratigraphy of shell concentrations. In: P.A. Allison and D.E.G. Briggs (eds.), Taphonomy: Releasing the Data Locked in the Fossil Record, 211–290. Plenum Press, New York.

DIANA L. BOYER, DAVID J. BOTTJER and MARY L. DROSER, 2004, Ecological Signature of Lower Triassic Shell Beds of the Western United States, PALAIOS, v. 19; no. 4; p. 372-380