Partner organizations: Other collaborators:
Joseph Carter, University of North Carolina Chapel Hill, NC Has been collaborating on major find in Norian of North Carolina Mark Norell, American Museum of Natural History Coauthor with us on Erpetosuchus from CT. Emma Rainforth, Columbia University (Ph.D. student) Nick Salkowski, Columbia University (Ph.D. student)
Activities and findings:
Research Activities: This project seeks to collect and analyze new tetrapod material (both skeletal and footprint) in Norian-age (Late Triassic, 202-218 Ma) strata of the Newark Supergroup rift basins of eastern North America as a prelude to understanding Triassic faunal provinciality and the Triassic-Jurassic mass extinction event. Our work to date has focused on finding productive tetrapod localities through the Late Triassic in Eastern North America. This has consisted of prospecting in likely lithologies by Olsen and a network of dedicated amateur volunteer paleontologists. Two Ph.D. students are working on the material for their theses and we have undertaken locally significant outreach lectures. Thus far we have found one major tetrapod site, just below the Triassic-Jurassic boundary, several other tetrapod bone sites of Rhaetian and Norian age, a large number of microvertebrate localities, and significant new footprint material. All material is studied with its stratigraphic and sedimentological context, particular with respect to the newly developed high-resolution timescale developed by Olsen and Kent (see below). New Skeletal material is being prepared by mechanical means by the preparation staff of the Royal Ontario Museum (under H-D. Sues), by Emma Rainforth (Ph.D. student supervised by Olsen) and by staff of the American Museum of Natural history (working with Olsen who is an AMNH Research Associate), and by negative preparation by Olsen and Rainforth. Microvertebrate material is being prepared by Nick Salkowski (Ph.D. student) and Olsen.
Research Findings: Our most important discovery to date on this project has been a very rich assemblage of tetrapod skeletal material from a late Rhaetian horizon about 600 ky older than the Triassic-Jurassic boundary (based on Milankovitch cyclostratigraphy), in the Jacksonwald syncline of the Newark rift basin. Most of the material consists of isolated bones and bone scraps, however, there is a surprising amount of articulated material. Most material is still being prepared, both at Columbia and at the Royal Ontario Museum, however we have been able to identify the following: 8 partial skulls of the procolophonid Hypsognathus fenneri; 3 partial articulated skeletions of same; 2 partial archosaur skeletons; fragmentary protosuchid crocodyliomorph post-cranial remains (c.f. Protosuchus); fragmentary cranial material of same; phytosaur teeth and post-cranial fragments; probable aetosaur osteoderms; many isolated procolophonid teeth and post-cranial elements. The material in total includes hundreds of elements. This surely comprises the largest assemblage of well-preserved tetrapod material so close to the Triassic-Jurassic boundary. No particular horizon at this site appears to be uniquely rich, rather all lithologies appear to produce some bone. It appears that this marginal lacustrine facies may be representative in its level of productivity. We note however, that its productivity is certainly related to the slight metamorphic effects of the adjacent Jacksonwad sill, which has resulted in unusually unweathered rock (and bone) very close to the ground surface. We have tested this hypothesis by examining other areas where construction excavation has revealed fresh rock of a similar marginal lacustrine facies. One site at a level about 4 my older than the Triassic-Jurassic boundary (?Early Rheatian). This site has produced fragmentary probably procolophonid and archosaur material, as well as the youngest representative of the probable ornithischian ichnite Atreipus. Another site about 12 million years older than the Triassic-Jurassic boundary (Early Norian), also in the Jacksonwald syncline, adjacent to the Birdsboro intrusion has produced as yet unprepared and unidentified bone material. We are encouraged by this discovery and believe our ongoing exploration for new sites are likely to yield much additional material from many horizons. An additional series of important finds are microvertebrate localities, examined by disaggregating carbonate-cemented siltstones and intraformational conglomerates. Our preliminary investigation shows that such microvertebrate-bearing lithologies are common and we have found productive sites at the following levels: Early Carnian (234 Ma.) limestone, Falling Creek Fm., Taylorsville basin, VA, lower Timesgadawine Fm., Argana basin, Morocco (funded from elsewhere), and intraformational conglomerate, basal Wolfville Fm., Nova Scotia, Canada; early Late Carnian (230 Ma.) mudstone, Richmond basin, VA and intraformational conglomerate, middle Wolfville Fm., Nova Scotia, Canada; Late Carnian (224 Ma.), limestone, Cumnock Fm., Wadesboro basin, NC; Late Carnian (222 Ma.), intraformational conglomerate, Lockatong Fm, Newark basin, PA; early Norian (~219 Ma.) limestone, Durham basin, NC; middle Norian (212 Ma) intraformational conglomerate, middle Passaic Fm., Newark basin, PA; late Norian (210 Ma), limestones, Bull Run Fm., Culpeper basin, VA; Early Rhaetian (209 Ma.), Middle Rhaetian (205 Ma.), Late Rheatian (202.5, 203 Ma.) limestones, Passaic Fm., Newark basin, PA.; early Hettangian (202 Ma.) limestone, Feltville Fm., Newark basin, Cass Brook Fm, Pomperaug basin, CT, and Scots Bay Fm., Fundy basin, Nova Scotia, Canada; early Hettangian (201.5 Ma.) limestone, East Berlin Fm., Hartford basin, CT, mudstone, Waterfall Fm., Culpeper basin,. VA; and middle Hettangian (201 Ma.) limestone, Portland Fm., Hartford basin, CT. A major advance is that all of the productive sites are ties to a common, high resolution, cyclo- and magnetostratigraphic timescale developed recently by Olsen and Kent via other NSF funding. We appear close to the realization of tetrapod skeletal sampling at at least the 2 my level for about 35 million years of the Triassic and Early Jurassic, and 500 ky level for immediately around the Triassic-Jurassic boundary. This should go a long way towards filling the so called Norian gap, cited by some authors as impeding our understanding of the Triassic-Jurassic faunal change. At this time it is clear that tetrapod assemblages in eastern North America slowly changed through the Late Triassic until the boundary with the Jurassic, where, based on the new skeletal there was a major faunal turnover over a maximum duration of about 700 ky. This turnover consisted of large-scale extinction without replacement, except for the appearance of larger theropod dinosaurs (thus far represented only by tracks), immediately after the boundary.
Research Training: The new material is forming the basis of two Columbia Ph.D. theses. Emma Rainforth (3rd yr) is working on the footprint and larger skeletal material around the Triassic-Jurassic boundary and Nick Salkowski (1st yr) is working on the microvertebrate assemblages. The following amateur volunteer paleontologists have been invaluable in this project: George Hrynewick (Nova Scotia), Charles Rizzo and Fred Castle (NJ), and Mike Sjzana and Brian Hartline, (PA). We have worked with these individuals paying special attention to their roles in outreach to the lay community and to their future education. We note that in the past some amateur paleontrologists that have been involved with past projects have gone onto professional careers in research and
Education and Outreach: We have undertaken educational outreach through a series of lectures (Olsen). including this year, the New Jersey Paleontological Society, the Hudson Valley Astronomy Society, the North Bergen Paleontological Society; and Lamont Open House.
Journal Publications:
http://www.ldeo.columbia.edu/~polsen/nbcp/trjworkinggroup.html
Summaries ongoing research on Triassic-Jurassic, including this award. Has index to specific award-related activities, including databases
Other specific products:
Contributions within Discipline:
This project adds substantially to our understanding of the Triassic-Jurassic Mass extinction, one of the 'big five' mass-extinctions of the last half billion years, as well as ancient biodiversity. As such, it makes important cointributions to paleobiology, vertebrate morphology and systematics, and stratigraphy,
Our results will have significant implications for evolutionary biology in understanding one of the largest episodes of evolutionary diversification and adaptive radiation following the Triassic-Jurassic mass extinction.
Our outreach program engages a broad sector of lay people some of whom become motivated to join the profession. Those that do not, have nonetheless, a greater appreciation and understanding for the history of life, evolution, and their place in the history of the Earth. We also feel strongly that our interaction fosters greater understanding of the scientific process as well.
Our web sites add to the infrastructure of science-related resources. In addition the more spectacular material we collect will eventually be displayed in museums and add to the general educational base.
Our study addresses mass extinctions, and hence provides needed background for understanding our present biodiversity crisis. In addition, the dramatic drop in diversity at the Triassic-Jurassic boundary and its slow recover thereafter, was synchronous with, and certainly interrelated to, major changes in atmospheric CO2 and the general C cycle as reflected in the delta-13C record, thus providing insight into the roles of biocomplexity in the Earth system, suggesting new avenues for additional research.
Special Requirements for Annual Project Report:
Unobligated funds: less than 20 percent of current funds Categories for which nothing is reported: Participants: Partner organizations Products: Other specific product Special Reporting Requirements Animal, Human Subjects, Biohazards