Permian/Triassic Transition

CP1

CP1 conglomerate

DH1

DH1 breccia

Just a few pics to ponder as the details are yet to be worked out.

Who's Collecting Crittenden Springs?

Jim Jenks is writing a paper on the Early Triassic ammonoids he has collected over the years at the Crittenden Springs locality north of Montello, Nevada. He went out a few weeks ago to take some photos of the beds he collected and found that someone has been out there recently. Large excavations and partially collected fossils is what he found.

One of the large holes found


A large Churkites noblei partially collected (notice the saw cut)

Another large hole where the beds were exposed. Jim says excavations like this have occurred in several places.

Complete fossiliferous bed shown here, Jim exposed these for a photo in his paper, he says quite a bit has been removed from this site too.

The collecting area is on BLM and Winecup-Gambel Ranch property. It would sure be nice to know who has been collecting here, whether it is someone from an institution or commercial collectors. This seems to be a larger excavation than someone who is digging for reasonable and/or personal use would need to dig.

Early Middle Ordovician Cephalopods

I went with Dan and his Paleo Class out into Utah's West Desert. We collected some trilobites from the Cambrian Wheeler Shale, some brachiopods from the Permian Gerster Limestone, and then some fossils from the Ordovician Juab Limestone and Kanosh Shale.

The first photo is a Tarphycerid from the Juab Limestone, the second, a large Endocerid in a block of limestone from the Kanosh Shale.

Just a note on the advantages of taking two vehicles into the desert, if the battery goes dead on one, you can take the other into town to get some jumper cables. Of course if one would have had the cables in the first place there would have been no need for the run to town. But without the other vehicle it would have been a nice 30 mile hike, or at least a good long wait for someone to happen by.
I would also like to thank the truck driver at the Border Inn who gladly gave up a spare set of jumper cables, he wouldn't take anything for them, said someone had helped him earlier so he was just passing it on; someone has a good deed coming.

Dan's Paleo class on the slopes of Fossil Mountain,
L-R Mike, Patty, Connie, Dan, Kevin and Salem

MC Anasibirites Beds

Permian on the left, Black Dragon (Moenkopi red beds on left), Thaynes and then more redbeds on right
(possibly Chinle conglomerate capping hills on right)

?Hemiprionites, Anasibirites and Wasatchites

Anasibirites beds (gray) in center, about 20-25cm thick, with small "body chamber beds" (15cm thick) below,
with high angle fault. Beds with Inyoites and Guodunites below, Thick 50-60cm brown bed.

Cool folding in basal beds of Thaynes Group.

Early Triassic Anasibirites Beds

The Anasibirites Beds in the Confusion Range (above) comprise approximately 30 cm of limestone packed with cephalopod shells. On a recent two week trip collecting fossils from a few new outcrops and a couple of classic ones, I noticed how similar they all are.

From the Cephalopod Gulch locality, near Salt Lake City, where Mathews first described the Anasibirites fauna in the Western US (above). Another approximately 30 cm bed packed with the same fossils.

Smiths Phalen Ranch locality near Currie Nevada (above), another ~30 cm of limestone containing Anasibirites and Wasatchites.

A new locality (to me) in south west central Utah, where beds containing the Anasibirites fauna also occur. This locality needs a little more collecting to verify the thickness and content of the beds, but they seem to be much the same as the others.

Localities to the east, like the Pahvant Range, San Rafael Swell and near Cedar City have the Anasibirites fauna though not as abundant as those to the north and west. Other localities like Crittenden Springs, Nevada, where Anasibirites and other Prionitids occur in lenses above the Meekoceras beds and a locality in Southeastern Idaho (Jim Jenks pers. com.), add to the data.

All these beds record a short time interval right after an extinction event near the end of the Smithian Stage of the Early Triassic.

Uintacrinus and Desmoscaphites bassleri

Uintacrinus from the Mancos Shale

a small fragment of Desmoscaphites bassleri

These fossils were found by Rod Scheetz (BYU Museum of Paleontology) in the Mancos Shale southeast of Green River. The small fragment he found closely matchs the one I found (see Aug. 12, 2009 post). I am now quite sure they are D. bassleri, and the small Scaphites is S. leei, from the Latest Santonian. D. bassleri has been found in the Upper Emery Sandstone northwest of Price and Northwest of Green River, so the Lower Emery Sandstone or it's equivalents are probably not present south and east of Green River as the fossils I found were in the lowest concretions above the Scaphites depressus (Latest Coniacian) beds.

REF:
Landman N. H. and Cobban W. A., 2007, Redescription of the Late Cretaceous (late Santonian) ammonite Desmoscaphites bassleri Reeside, 1927, from the Western Interior of North America. University of Wyoming, Rocky Mountain Geology, v.42, no.2, p.67-94

Spathian? Ammonoids

Small ammonoids and orthoconic nautiloids found in a gray limestone concretion. Probably from the Spathian part of the Formation

Jack Rabbit

Earthquake damage in Wells, Nevada, waiting to be repaired?

The Ranch, in the distance, and what outcrops there are in the foreground.

Outcrops of Smithian rocks were not found on this trip :(

vermiformis? Beds

a small Scaphites from low in the ?Lower Emery SS beds of the Mancos Shale east of Green River.

Body chamber from Clioscaphites ?vermiformis. These seem to have a lot more ribs than typical C. vermiformis.