2005 Salt Lake City Annual Meeting (October 16–19, 2005)

Paper No. 22
Presentation Time: 8:00 AM-12:00 PM

HIGH RESOLUTION BIOSTRATIGRAPHIC CORRELATION OF ACRITARCH DIVERSITY IN THE NEOPROTEROZOIC AND EARLIEST CAMBRIAN USING CONOP9


COHEN, Phoebe A., Earth and Planetary Sciences, Harvard University, Botanical Museum, 26 Oxford Street, Cambridge, MA 02138, pacohen@fas.harvard.edu

Acritarchs are organic-walled, acid-resistant microfossils believed to be the cysts of eukaryotic protistan phytoplankton and/or non-photosynthesizing heteromorphic microbial eukaryotes. They are organized by morphological taxonomy due to the uncertainty surrounding their phylogenetic identities. Acritarchs have high morphological diversity and abundance in the Neoproterozoic and the early Phanerozoic making them excellent biostratigraphic tools. In this study, I used the stratigraphic correlation program CONOP9, written by P. Sadler, to investigate the acritarch record during the late Neoproterozoic and earliest Cambrian in order to obtain a better picture of eukaryotic diversity during this critical time in earth history. I analyzed Neoproterozoic sections from the Officer Basin, Australia and Cambrian boundary sections from the Lublin Slope, Poland using CONOP9 and compared results to the original biostratigraphic analysis. The results show that CONOP9 increases the stratigraphic resolution of the sections under study by approximately an order of magnitude over previous reports. In the Neoproterozoic sections, the increased resolution indicates that the Acraman impact was not the sole factor in determining acritarch diversity patterns in the Officer Basin. In the Cambrian sections, the increased resolution provides a more nuanced picture of diversity across the boundary than is achieved with the traditional biozone method. This study shows the importance of using more advanced stratigraphic correlation methods when examining the paleontological record.