Study of an Ordovician Carbonate with Alternating Dolomite–Calcite Laminations and Its Implication For Catalytic Effects of Microbes On the Formation of Sedimentary Dolomite
A Holocene “Frozen Accident”: Sediments of Extreme Paleofloods and Fires in the Bedrock-Confined Upper Huis River, Western Cape, South Africa
Calcium Carbonate Precipitation in Diatom-rich Microbial Mats: The Laguna Negra Hypersaline Lake, Catamarca, Argentina
COVER EXPLANATION.—Cluster of decimeter-size, partially exposed carbonate stromatolitic oncoids (upper half and lower left and right corners). In the center, note the smaller size, subaqueous oncoid covered by a thin, pink to orange colored biofilm where abundant carbonate precipitation takes place. These are associated with well-stratified pink to orange microbial mats typically seen in the Laguna Negra hypersaline lake, a high-altitude Andean lake in Catamarca Province, Argentina. See Gomez et al., this issue.