EVIDENCE OF FRESH WATER LIMESTONE (BOUSE FORMATION EQUIVILENT?) IN THE TRANSGESSIONAL-REGRESIONAL MARINE AND NON-MATINE IMPERIAL GROUP SEDIMENTS, COYOTE MOUNTAINS, IMPERIAL COUNTY, SALTON TROUGH, SOUTHERN CALIFORNIA

Within two of the six+ transgressional and regressional sequences of the Imperial Group found in the Coyote Mountains are what appear to be two fresh water limestones. The first and lowest appears at the bottom of the Garnet Formation, a non-marine fanglomerate in the Imperal Group, and is approximately two+ meters thick with a tuffa cap. In other areas of the Garnet Formation, this limestone is much thinner. The second and highest limestone appears in the next higher non-marine fanglomerate in the Imperial Group, is less than a meter thick and exposed in only one location. No fossils are seen in either limestones.

Using Winker and Kidwell (1996) figure 2, a reconstruction of the Salton Tough, the Coyote Mountains and the deposition environment of the Imperial Group sediments would be south of Yuma, Arizona and south of the mouth of the Colorado River. With the Coyote Mountains in this location, the Colorado River could supply fresh water to the depositional environments of the non-marine fanglomerates. The limestones that are found in the Coyote Mountains represent a environment south of Yuma, Arizona that is similar to the environment that produced the Bouse Formation north of Yuma Arizona.