![Earth and Planetary Sciences ETDs](../../assets/md5images/c8d35991e3c821f53809b32caadf6933.png)
Earth and Planetary Sciences ETDs
Publication Date
2-1-2012
Abstract
Paleomagnetic data obtained from the Upper Triassic to Lower Jurassic strata of the Moenave Formation, southern Utah and northern Arizona, were used to construct a composite magnetostratigraphy and further refine the position of the base of the Jurassic in the southwest U.S.A. The composite magnetostratigraphy provides a chronostratigraphic framework to tie Triassic-Jurassic sedimentation in the southwest U.S.A to marine strata in the United Kingdom, Turkey, and Italy, and to the Pangean rift history including extrusive igneous rocks, preserved in Morocco, and in the Newark Basin, northeast U.S.A. In addition, paleomagnetic data from the Moenave Formation were used to calculate a pole position for North America for the latest Triassic to earliest Jurassic time. A lesser amount of inclination error, flattening factor of 0.78, is record in Moenave Formation strata compared to observation from coeval Newark Basin strata. The new paleomagnetic pole position for North America, corrected for inclination error and 4° of clockwise Colorado Plateau rotation is located at 62.3° N, 68.0° E (A95 = 7.4°, N = 102). Pole positions from the southwest U.S.A. continue to indicate a westerly pole position for North America at the latest Triassic to earliest Jurassic time. A mid-Pleistocene lake sedimentary record obtained from the Valles Caldera, northern New Mexico was investigated using rock magnetic and paleomagnetic techniques. Lake sediments span three glacial and two interglacial intervals, MIS 14 – 10. Both detrital and diagenetic phases are preserved in sediment throughout the core. Preservation of detrital phases indicates well mixed lake conditions were more common during interglacial intervals. Discrete intervals of diagenetic phases indicate anoxic conditions are more common in sediments deposited during glacial intervals. A series of anoxic intervals are identified in sediment deposited during MIS 12 that are closely related to interstadial events characterized by increased Cyperaceae and Juniper pollen counts and increased mean annual temperatures. Paleomagnetic data are mostly normal polarity consistent with Brunhes normal polarity chron. However, paleomagnetic data combined with relative paleointensity records support the presence of three geomagnetic field phenomena 14±/Calabrian Ridge II at ~536 ka, 11± at ~400 ka, and Levantine at ~360-360 ka.
Degree Name
Earth and Planetary Sciences
Level of Degree
Doctoral
Department Name
Department of Earth and Planetary Sciences
First Committee Member (Chair)
Fawcett, Peter J.
Second Committee Member
Roy, Mousumi
Third Committee Member
Wawrzyniec, Tim F.
Fourth Committee Member
Lucas, Spencer G.
Fifth Committee Member
Goff, Fraser
Project Sponsors
Institute of Geophysics and Planetary Physics at Los Alamos National Laboratory, Sloan Foundation, National Science Foundation, Department of Earth and Planetary Sciences, Institute for Rock Magnetism at the University of Minnesota, Twin Cities, New Mexico Geological Society student grants, American Geosciences Institute Minority Participation Program, New Mexico Alliance for Graduate Education and the Professorate
Language
English
Keywords
Paleomagnetism, Rock Magnetism, Lacustrine sediment, red beds, Latest Triassic to earliest Jurassic, mid-Pleistocene
Document Type
Dissertation
Recommended Citation
Hurley, Linda Lee Donohoo. "Magnetic records from latest Triassic to earliest Jurassic red beds, Utah and Arizona, and from mid-Pleistocene lake beds, New Mexico." (2012). https://digitalrepository.unm.edu/eps_etds/38