Boulder, Colo. - The December issue of the GSA BULLETIN includes research on a range of newsworthy topics including a probable volcano eruption in Peru, estuaries being key to helping prevent erosion, and plate movement in central California.
Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to the GSA BULLETIN in stories published. Contact Ann Cairns for copies of articles and for additional information or assistance.
Chemical sedimentology and paleoenvironmental history of Lake Olduvai, a Pliocene lake in northern Tanzania. R.L. Hay, Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA, and T.K. Kyser, Department of Geological Sciences, Queens University, Kingston, Ontario K7L 3N6, Canada. Pages 1505 - 1521.
The Olduvai basin of northern Tanzania was inhabited by at least two types of hominids in Pliocene Pleistocene time, and their remains and associated archaeological materials have been found in sedimentary deposits bordering a former saline lake that is here termed Lake Olduvai. Lacustrine deposits of Lake Olduvai provide a sedimentary record of about 200,000 years, from ~1.9-1.7 million years ago.
The main goal of this study is the paleoenvironmental history of the lake as determined from evidence of water depth, areal extent, and water chemistry. Lacustrine minerals indicate that the lake fluctuated widely in salinity and was most saline late in its history. Evidence suggests an overall trend toward a hotter and drier climate that was punctuated by wetter- and drier-than-average episodes that may have lasted as much as 1,000 years or more.
Net ebb sediment transport in a rock-bound, mesotidal estuary during spring-freshet conditions: Kennebec River estuary, Maine. Michael S. Fenster, et al. Environmental Studies Program, Randolph-Macon College, Ashland, Virginia 23005, USA. Pages 1522-1531.