Tectonic significance of regional Late Paleozoic remagnetization of miogeoclinal carbonate rocks in the Great Basin and adjacent areas
- Univ. of Nevada, Reno, NV (United States). Dept. of Geosciences
- Univ. of New Mexico, Albuquerque, NM (United States). Dept of Geology
Regional remagnetization has been documented in more than 20 out of almost 40 stratigraphic sections of relatively unmetamorphosed Paleozoic miogeoclinal carbonate rocks extending roughly NE-SW from the Stansbury Mountains of north-central UT to the Nopah Range in eastern CA. The units range from Middle Cambrian to Pennsylvanian in age. Gray limestones in a section in the eastern Grand Canyon on the Colorado Plateau show only Cenozoic magnetizations, as to sections adjacent to the Plateau. The magnetization fails micro-fold tests from late compaction fabrics in Lower Ordovician limestones in the Egan Range of central NV, the Desert Range of southern NV, and the House Range of western UT. In addition, the magnetization fails a conglomerate test in the Devonian Stansbury Formation: directions from clasts of older Paleozoic rocks in this unit are not scattered, and coincide with those from the matrix material. However, the low inclination with respect to bedding, and improved clustering on correction for bedding tilt, suggest this magnetization is pre-Mesozoic. Consistently reversed polarity suggests a Kiaman (late Paleozoic) age. The regional magnetic signature probably reflects tectonic events in this part of the Cordillera at the close of the Paleozoic, such as emplacement of the Golconda allochthon in central NV during the Sonoma Orogeny. It may also be linked to the late Paleozoic development of a system of yoked basins and uplifts that extend northwesterly from west TX through central UT. The remagnetization in most sections is possibly caused by magnetite precipitated from fluids mobilized by tectonic compression, as has been proposed for Kiaman remagnetization in the Appalachians. Regional variations of the remagnetization could help resolve the timing of tectonic deformation and allochthon emplacement during the formation of a convergent boundary in the Cordillera during Permo-Triassic time.
- OSTI ID:
- 5022406
- Report Number(s):
- CONF-9305259--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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