Christopher A. Scholz¹, Eugene B. Karabanov², Kiram Lezzar³, Douglas F. Williams², M.I. Kuzmin⁴, John King⁵, John Peck⁶

(1) Syracuse University, Syracuse, NY
(2) Univ. of South Carolina
(3) Syracuse University
(4) Institute of Geochemistry, Russian Academy of Sciences
(5) Univ. of Rhode Island
(6) Univ. of Akron

ABSTRACT: Facies Architecture of the Academician Ridge Accommodation Zone, Lake Baikal Rift, Siberia, determined from Multichannel Seismic Reflection Data and Baikal Drilling Project Drill Cores

The Academician Ridge is a bathymetric and structural high that separates the North and Central basins of Lake Baikal, the world's deepest and oldest lake. This locality presently receives only limited inputs of hemipelagic sediment, and sedimentation rates (~4 cm/kyr) are much slower than other sites in the lake. More than 350 km of multichannel seismic data and two drill cores were acquired on the ridge, and are used to develop a chronostratigraphic framework for the accommodation zone, representing ~10-12 million years of nearly continuous sedimentation. Seismic facies in the vicinity of the drill holes vary dramatically from the base of the section to the lake surface. Synthetic seismograms constructed from downhole geophysical logs and from physical properties measurements of drill core are used to correlate the seismic reflection data to lithofacies. This correlation permits us to extend the depositional facies interpretations throughout the seismic data set and across the ridge. Seismic facies near the base of the section are represented by discontinuous chaotic facies characteristic of coarse alluvial deposits that were deposited during incipient phases of extension. Low frequency, high amplitude and high-continuity seismic facies at the BDP98 drill site are correlated with proximal deltas and sublacustrine fan deposits, and correlate along strike to a distinctive zone of bi-directionally downlapping reflections indicative of a subaerial coarse-grained delta. Successive seismic facies contain high-amplitude, high-frequency reflections, characteristic of present-day hemipelagic sedimentation. This site illustrates how deltaic reservoir facies that form early can later become uplifted and encased in source-rock facies, producing an attractive syn-rift play.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado