Phase 1 of the Colorado Plateau Coring Project (CPCP-I) recovered a total of over 850m of stratigraphically overlapping core from three coreholes at two sites in the Early to Middle and Late Triassic age largely fluvial Moenkopi and Chinle formations in Petrified Forest National Park (PFNP), northeastern Arizona, USA. Coring took place during November and December of 2013 and the project is now in its post-drilling science phase. The CPCP cores have abundant detrital zircon-producing layers (with survey LA-ICP-MS dates selectively resampled for CA-ID-TIMS U-Pb ages ranging in age from at least 210 to 241 Ma), which together with their magnetic polarity stratigraphy demonstrate that a globally exportable timescale can be produced from these continental sequences and in the process show that a prominent gap in the calibrated Phanerozoic record can be filled. The portion of core CPCP-PFNP13-1A for which the polarity stratigraphy has been completed thus far spans ~ 215 to 209Ma of the Late Triassic age, and strongly validates the longer Newark-Hartford Astrochronostratigraphic-calibrated magnetic Polarity Time-Scale (APTS) based on cores recovered in the 1990s during the Newark Basin Coring Project (NBCP). Core recovery was ~ 100% in all holes (Table 1). The coreholes were inclined ~ 60-75° approximately to the south to ensure azimuthal orientation in the nearly flat-lying bedding, critical to the interpretation of paleomagentic polarity stratigraphy. The two longest of the cores (CPCP-PFNP13-1A and 2B) were CT-scanned in their entirety at the University of Texas High Resolution X-ray CT Facility in Austin, TX, and subsequently along with 2A, all cores were split and processed at the CSDCO/LacCore Facility, in Minneapolis, MN, where they were scanned for physical property logs and imaging. While remaining the property of the Federal Government, the archive half of each core is curated at the NSF-sponsored LacCore Core Repository and the working half is stored at the Rutgers University Core Repository in Piscataway, NJ, where the initial sampling party was held in 2015 with several additional sampling events following. Additional planned study will recover the rest of the polarity stratigraphy of the cores as additional zircon ages, sedimentary structure and paleosol facies analysis, stable isotope geochemistry, and calibrated XRF core scanning are accomplished. Together with strategic outcrop studies in Petrified Forest National Park and environs, these cores will allow the vast amount of surface paleontological and paleoenvironmental information recorded in the continental Triassic of western North America to be confidently placed in a secure context along with important events such as the giant Manicouagan impact at ~ 215:5 Ma (Ramezani et al., 2005) and long wavelength astronomical cycles pacing global environmental change and trends in atmospheric gas composition during the dawn of the dinosaurs.
Bibliographical noteFunding Information:
We thank the National Park Service and particularly superintendent Brad Traver for permission to core in the park and for logistical support during site selection and drilling. Primary funding for this project is from NSF collaborative grants EAR 0958976 (Olsen, Geissman), 0958859 (Kent), 0959107 (Gehrels), 0958723 (Mundil), 958915 (Irmis) and ICDP (International Scientific Continental Drilling Program grant 05-2010: Geissman, Olsen, Sha, Molina-Garza, Kürschner, Bachmann), and we thank the late Richard Lane of NSF and Ulrich Harms for their persistent guidance through the funding process. We acknowledge support for the LaserChron Center from EAR 1649254, for the LacCore Facility from EAR 1462297 and EAR 0949962, and for CSDCO Facility from EAR 1338322, and for the University of Texas High Resolution X-ray CT Facility from EAR 1258878. The palynological and organic geochemisty research was funded by the FRINATEK grant no. 213985 (Kürschner), FRINATEK overseas travel grant 244926/BG (Kürschner/Miller) and funding from the Faculty of Mathematics and Natural Sciences at the University of Oslo (Norway) (Kürschner/Baranyi) and the Lamont-Climate Center. We are very grateful to the on-site core-handling volunteers Justin Clifton, Bob Graves, Ed Lamb, Max Schnurrenberger, and Brian Switek for their round-the-clock efforts! We also thank Nancy Riggs (Northern Arizona University) for helpful discussion. All thermal demagnetization data and all anisotropy of magnetic susceptibility (AMS) data collected by Ziaul Haque, PhD candidate, University of Texas at Dallas. Jingeng Sha acknowledges support from the National Natural Science Foundation of China (41730317), Special Basic Program of Ministry of Science and Technology of China (2015FY310100), and Bureau of Geological Survey of China and National Committee of Stratigraphy of China (DD20160120-04). This is a contribution to IGCP-632, LDEO Contribution 8231, and Petrified Forest Paleontological Contribution 55.