CARBONATE-CARBON ISOTOPE STRATIGRAPHY AND THREE-DIMENSIONAL SUBSIDENCE HISTORY OF THE PENNSYLVANIAN ELY-BIRD SPRING BASIN, NEVADA AND UTAH
We present data and correlations from six EBSB sections, including (from north to south) Grindstone Mountain (n=243), Illipah Reservoir (n=227), Mountain Home Range (n=183), Syncline Ridge (n=159), Arrow Canyon (n=107), and Mountain Springs Pass (n=183). The bulk of these data are dominated by 0.5 to 2‰ positive shifts toward cyclothem tops built on longer-scale/lower-frequency isotopic and stratigraphic cycles. Correlations between sections were investigated using Match-2.3 (Lisiecki and Lisiecki, 2002), a dynamic programming algorithm developed for stratigraphic signal correlation. For each correlation, Match also produces a “relative accumulation rate” curve, interpreted here as a proxy for relative accommodation space generation. All correlations are referenced to the mid-basin section at Illipah Reservoir (IR) in the west-central EBSB.
In lower Morrowan time, the EBSB sections to the south and north have similar to lower accumulation rates than IR, whereas the Mountain Home Range section to the east accumulated sediment ~1.5 times faster. Relative accumulation rates surpass IR throughout upper Morrowan time around the EBSB, except in the south where accumulation rates remain lower than IR. During Atokan time, relative accumulation rates in the central and southern EBSB are similar to lower than that at IR, but are >2 times faster than IR at Grindstone Mountain in the northwestern EBSB. Atokan accommodation space generation in the northwestern EBSB may be the first signal of a tectonic event that culminated in angular unconformities and overturned folding that deformed the northern EBSB during middle Pennsylvanian time.