|2009 Portland GSA Annual Meeting (18-21 October 2009)|
|Paper No. 32-12|
|Presentation Time: 9:00 AM-6:00 PM|
FOSSIL CHARCOAL IN CHINLE GROUP STRATA (UPPER TRIASSIC), NORTHERN ARIZONA: DISTRIBUTION AND SIGNIFICANCE
TANNER, Lawrence H., Dept. Biological Sciences, Le Moyne College, 1419 Salt Springs Rd, Syracuse, NY 13214, email@example.com and LUCAS, Spencer G., New Mexico Museum of Natural History and Science, 1801 Mountain Road N.W, Albuquerque, NM 87104|
Previous studies have suggested that fusain (fossil charcoal) is scarce in sedimentary rocks of Late Triassic age. This apparent lack was cited as evidence for an infrequent occurrence of wildfire and of relatively low levels (compared to modern) of atmospheric oxygen during this time interval, thereby supporting earlier geochemical models based on mass balance and isotope fractionation calculations. We report here new discoveries in northern
In concert with prior reports from Carnian- to Norian-age strata of the Chinle and Fundy groups (Chama and Fundy basins, respectively), these findings demonstrate a significantly greater abundance of fusain in Upper Triassic strata than previously acknowledged. We further suggest that these findings indicate that wildfire was not an unusual occurrence during the Late Triassic. This conclusion supports more recent experimental studies and geochemical models that indicate atmospheric oxygen levels at or above modern levels during the Late Triassic. Robust levels of atmospheric oxygen during the Late Triassic are consistent with the widespread deposition of coals, and may be linked with the first appearance of mammals, and of pterosaurs and dinosaurs, whose evolutionary success likely resulted from their enhanced, oxygen intensive metabolisms.
2009 Portland GSA Annual Meeting (18-21 October 2009)
General Information for this Meeting
|Session No. 32--Booth# 134|
Paleontology: Paleoenvironments, Paleocommunities, Biogeography & Biostratigraphy (Posters)
Oregon Convention Center: Hall A
9:00 AM-6:00 PM, Sunday, 18 October 2009
Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 103
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