Sundance Formation

{{Short description|Geological formation in Western North America}}

{{Infobox rockunit

| name = Sundance Formation

| image =

| caption =

| type = Geological formation

| period = Callovian

| age = Bathonian - Oxfordian {{fossilrange|168|157}}

| prilithology = shale

| otherlithology = limestone, sandstone

| namedfor =Sundance, Wyoming

| namedby =Darton

| region = Western North America

| country = United States

| coordinates =

| unitof =

| subunits =Canyon Springs Sandstone Member, Hulett Sandstone Member, Lak Member, Pine Butte Member, Redwater Shale Member, Stockade Beaver (Shale) Member, Windy Hill Sandstone Member

| underlies = Morrison Formation

| overlies = Gypsum Springs Formation

| thickness =Up to 100 m

| extent =

| area =

| map =

| map_caption =

|year_ts=1904}}

The Sundance Formation is a western North American sequence of Middle Jurassic to Upper Jurassic age{{cite journal|last = Jennings|first = Debra S.|author2=Stephen T. Hasiotis |title = Taphonomic analysis of a dinosaur feeding site using Geographic Information Systems (GIS), Morrison Formation, Southern Bighorn Basin, Wyoming, USA|journal = PALAIOS |date=2006|volume=21|issue=5|pages=480–492|publisher=SEPM Society for Sedimentary Geology|doi=10.2110/palo.2005.P05-062R| s2cid=55369947 | url=http://doc.rero.ch/record/13869/files/PAL_E796.pdf }} Dating from the Bathonian to the Oxfordian, around 168-157 Ma, It is up to 100 metres thick{{Cite journal|last1=Syzdek|first1=Joseph|last2=Malone|first2=David|last3=Craddock|first3=John|date=2019-08-01|title=Detrital Zircon U-Pb Geochronology and Provenance of the Sundance Formation, Western Powder River Basin, Wyoming|url=http://dx.doi.org/10.31582/rmag.mg.56.3.295|journal=The Mountain Geologist|volume=56|issue=3|pages=295–317|doi=10.31582/rmag.mg.56.3.295|s2cid=210290670 |issn=0027-254X|url-access=subscription}} and consists of marine shale, sandy shale, sandstone, and limestone deposited in the Sundance Sea, an inland sea that covered large parts of western North America during the Middle and early Late Jurassic.

Geology

The Sundance Formation underlies the western North American Morrison Formation, the most fertile source of dinosaur fossils in the Americas, and is separated by a disconformity from the underlying Middle Jurassic Gypsum Springs Formation.

=Fossils=

The Sundance Formation is known for fossils of an extinct species of marine cephalopod, the belemnite Pachyteuthis densus, as well as several extinct species of oyster, including Deltoideum, Liostrea, and Gryphaea nebrascensis. Other common invertebrates include crinoids, echinoids, gastropods, insects, ostracods, and foraminifera.{{Cite journal |last1=Mcmullen |first1=Sharon K. |last2=Holland |first2=Steven M. |last3=O'keefe |first3=F. Robin |date=June 2014 |title=The Occurrence of Vertebrate and Invertebrate Fossils in a Sequence Stratigraphic Context: The Jurassic Sundance Formation, Bighorn Basin, Wyoming, U.S.A. |url=https://bioone.org/journals/palaios/volume-29/issue-6/pal.2013.132/THE-OCCURRENCE-OF-VERTEBRATE-AND-INVERTEBRATE-FOSSILS-IN-A-SEQUENCE/10.2110/pal.2013.132.full |journal=PALAIOS |volume=29 |issue=6 |pages=277–294 |doi=10.2110/pal.2013.132 |s2cid=126843460 |issn=0883-1351|url-access=subscription }}

Fossil dinosaur 'footprints' on an ancient ocean shoreline are preserved in the formation and protected at the Red Gulch Dinosaur Tracksite, located in the Bureau of Land Management Red Gulch/Alkali National Back Country Byway, near Shell in Big Horn County, Wyoming.[http://www.blm.gov/wy/st/en/field_offices/Worland/Tracksite.html BLM−Bureau of Land Management, Wyoming Office: "Red Gulch Dinosaur Tracksite" website], info, maps, photo gallery, accessed 8.21.2015

Paleobiota

= Vertebrates =

class="wikitable" align="center" width="100%"
Genus ! Species ! Member ! Material ! Notes
style="background:#FEF6E4;"\| PteraichnusLockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." Zitteliana. B28. p. 187-198. {{ISSN\|1612-4138}}. \|style="background:#FEF6E4;"\| P. stokesi \|style="background:#FEF6E4;"\| Alcova/Grey Reef Reservoir, Seminoe Reservoir and Bighorn Canyon National Recreation area. (Wyoming) \|style="background:#FEF6E4;"\| Trace fossils \|style="background:#FEF6E4;"\| A Pteraichnid belonging to the Pterodactyloidea.
Tatenectes \| T. laramiensis \| Redwater Shale Member \| \| A Cryptoclidid Plesiosaur.
Pantosaurus \| P. striatus \| Redwater Shale Member \| \| A Cryptoclidid Plesiosaur.
Megalneusaurus \| M. rex \| Redwater Shale Member \| \| A Thallasophonid Pliosaur.
Baptanodon \| B. natans \| Redwater Shale Member \| \| An Ophthalmosaurid Ichthyosaur.
style="background:#E6E6E6;"\| Plesiosaurus \|style="background:#E6E6E6;"\| "P." shirleyensis \|style="background:#E6E6E6;"\| \|style="background:#E6E6E6;"\| Material now lost.W. R. O'Keete, F. R. and Wahl [https://core.ac.uk/download/pdf/232711244.pdf Current taxonomic status of the plesiosaur Pantosaurus striatus from the Upper Jurassic Sundance Formation, Wyoming], article on pages 37-47 of the complete issue, 2003, Paludicola, 4 (2) : 27-68. Paperback – January 1, 2003 \|style="background:#E6E6E6;"\| Possibly a Plesiosaurid Plesiosaur.

class="wikitable" align="center" width="100%"

Genus

! Species

! Member

! Material

! Notes

style="background:#FEF6E4;"|

PteraichnusLockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." Zitteliana. B28. p. 187-198. {{ISSN|1612-4138}}.

|style="background:#FEF6E4;"|

P. stokesi

|style="background:#FEF6E4;"|

Alcova/Grey Reef Reservoir, Seminoe Reservoir and Bighorn Canyon National Recreation area. (Wyoming)

|style="background:#FEF6E4;"|

Trace fossils

|style="background:#FEF6E4;"|

A Pteraichnid belonging to the Pterodactyloidea.

Tatenectes

T. laramiensis

Redwater Shale Member

A Cryptoclidid Plesiosaur.

Pantosaurus

P. striatus

Redwater Shale Member

A Cryptoclidid Plesiosaur.

Megalneusaurus

M. rex

Redwater Shale Member

A Thallasophonid Pliosaur.

Baptanodon

B. natans

Redwater Shale Member

An Ophthalmosaurid Ichthyosaur.

style="background:#E6E6E6;"|

Plesiosaurus

|style="background:#E6E6E6;"|

"P." shirleyensis

|style="background:#E6E6E6;"|

Material now lost.W. R. O'Keete, F. R. and Wahl [https://core.ac.uk/download/pdf/232711244.pdf Current taxonomic status of the plesiosaur Pantosaurus striatus from the Upper Jurassic Sundance Formation, Wyoming], article on pages 37-47 of the complete issue, 2003, Paludicola, 4 (2) : 27-68. Paperback – January 1, 2003

|style="background:#E6E6E6;"|

Possibly a Plesiosaurid Plesiosaur.

= Invertebrates =

class="wikitable" align="center" width="100%"
Genus ! Species ! Member ! Material ! Notes
Pachyteuthis \| P. densus \| \| \| A Belemnoid.

class="wikitable" align="center" width="100%"

Genus

! Species

! Member

! Material

! Notes

Pachyteuthis

P. densus

A Belemnoid.

= Fish =

class="wikitable" align="center" width="100%"
Genus ! Species ! Member ! Material ! Notes
Occithrissops \| O. willsoni \| \| \| An ichthyodectiform
Caturus \| C. dartoni \| \| \| A caturid amiiform
Hybodontiformes \| indeterminate \| Redwater Shale Member \| Teeth \| Belongs to a group of shark like cartilaginous fish called the Hybodontiformes. This might either be Hybodus or Asteracanthus.{{Cite journal \|last=Massare \|first=Judy A. \|last2=Wahl \|first2=William R. \|last3=Ross \|first3=Mike \|last4=Connely \|first4=Melissa V. \|date=January 2014 \|title=Palaeoecology of the marine reptiles of the Redwater Shale Member of the Sundance Formation (Jurassic) of central Wyoming, USA \|url=https://www.cambridge.org/core/journals/geological-magazine/article/abs/palaeoecology-of-the-marine-reptiles-of-the-redwater-shale-member-of-the-sundance-formation-jurassic-of-central-wyoming-usa/8D994E7059CB1FDCFB5A7B073C64D3AA \|journal=Geological Magazine \|language=en \|volume=151 \|issue=1 \|pages=167–182 \|doi=10.1017/S0016756813000472 \|issn=0016-7568 \|via=Geological Magazine\|url-access=subscription }} Found in association with Tatenectes.

class="wikitable" align="center" width="100%"

Genus

! Species

! Member

! Material

! Notes

Occithrissops

O. willsoni

An ichthyodectiform

Caturus

C. dartoni

A caturid amiiform

Hybodontiformes

indeterminate

Redwater Shale Member

Teeth

Belongs to a group of shark like cartilaginous fish called the Hybodontiformes. This might either be Hybodus or Asteracanthus.{{Cite journal |last=Massare |first=Judy A. |last2=Wahl |first2=William R. |last3=Ross |first3=Mike |last4=Connely |first4=Melissa V. |date=January 2014 |title=Palaeoecology of the marine reptiles of the Redwater Shale Member of the Sundance Formation (Jurassic) of central Wyoming, USA |url=https://www.cambridge.org/core/journals/geological-magazine/article/abs/palaeoecology-of-the-marine-reptiles-of-the-redwater-shale-member-of-the-sundance-formation-jurassic-of-central-wyoming-usa/8D994E7059CB1FDCFB5A7B073C64D3AA |journal=Geological Magazine |language=en |volume=151 |issue=1 |pages=167–182 |doi=10.1017/S0016756813000472 |issn=0016-7568 |via=Geological Magazine|url-access=subscription }} Found in association with Tatenectes.

References

Category:Jurassic geology of South Dakota

Category:Jurassic geology of Wyoming

Category:Jurassic System of North America

Category:Upper Jurassic Series

Category:Geology of the Rocky Mountains

Category:Geologic formations of Montana

Category:Geologic formations of Wyoming

Category:Paleontology in Wyoming

Category:Middle Jurassic Series

Category:Bathonian Stage

Category:Callovian Stage

Category:Oxfordian Stage

Category:Shale formations of the United States

Category:Limestone formations of the United States

Category:Sandstone formations of the United States