Anasibirites Bed Study
A 5.25 square meter area on top of the Anasibirites Bed in the Triassic
Thaynes Formation of West Central Utah was uncovered, photographed, and
mapped. Just the cephalopods that were fully exposed, and
complete
enough for orientation determination were mapped. The area was
excavated
and photographed in October, 1997. It was collected by me in
September,
1998, and by others, both known, and unknown, since. A small
outcrop
about 200m north of the mapped area provided samples for the cross
section,
the two units are easily correlated with the 20-50mm shale bed below
the
top section.
The
Anasibirites Beds are about 200 to 305 millimeters thick, and are
packed
with cephalopods. Studies that could be done on the beds to find
out why they accumulated include:
Anasibirites Beds Inyoites
Beds Meekoceras Beds
Conclusions
(in prep.)
The top
of
the Anasibirites Bed during mapping
- Semelparous activity (like spawning Salmon)
- Toxic environment (anoxia etc.)
- Condensed (low sediment deposition over time)
- Washed in
Faunas
Anasibirites Beds Inyoites
Beds Meekoceras Beds
Conclusions
(in prep.)