Duration, origin, and cyclostratigraphy of depositional cycles [in] the Devonian Lost Burro Formation, Death Valley, CA

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5880218

Yang, W; Kominz, M A ^[1]

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1. Univ. of Texas, Austin, TX (United States). Dept. of Geological Sciences

The measured type Lost Burro Formation in Lost Burro Gap, northern Panamint Range, California is composed of 186m of peritidal limestone, minor dolomite, and few quartz arenite beds. Detailed meter- to centimeter-scale studies of lithology, sedimentary structure, fossil assemblage, and petrography revealed repetitive stacking patterns of subtidal, intertidal, and supratidal facies. Gamma analysis tests the assumptions that cycles are periodic with equal durations and that each facies has a unique time-thickness relation defined as gamma=time/thickness. Gamma values of the 54 cycles fluctuate widely, indicating that the cycles do not have equal durations. Thus, the 54 cycles were subdivided into two groups of different mean durations. The process was repeated, dividing the 54 cycles into four subgroups of different mean durations. The process was repeated, dividing the 54 cycles into four subgroups of different mean durations. Strikingly constant gammas of three of the four subgroups indicate that cycles in each of these subgroups have approximately equal durations. The effective accumulation rates of the subtidal, intertidal, and supratidal facies were calculated from gamma values calibrated by mean cycle durations. They were used to convert the facies thicknesses into time. The resultant minimum time span of the measured section is 1,274.3ky. About a dozen statistically significant spectral peaks were found in the gamma-corrected spectrum of the Lost Burro record. Calibrated spectral peaks match nine Milankovitch eccentricity, obliquity, and precession index peaks as predicted for 377 Ma. Thus, Milankovitch climatic forcing is suggested for the deposition of the Lost Burro cycles in a period when continental glaciations was not active.

• OSTI ID: 5880218
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
CALIFORNIA
DEVELOPED COUNTRIES
DEVONIAN PERIOD
DIMENSIONS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGY
LITHOLOGY
MINERALOGY
NORTH AMERICA
ORBITS
ORIGIN
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
PETROGRAPHY
PETROLOGY
PRECESSION
STRATIGRAPHY
THICKNESS
USA