Abstract This volume is the fourth decadal compendium of research on the Belt Supergroup. It is an outgrowth of Belt Symposium IV, held in Salmon, Idaho, in July, 2003, in conjunction with the Tobacco Root Geological Society annual field conference. A full abstract and field–trip volume for that meeting is Lageson and Christner (2003) . In keeping with previous Belt Symposia, the scope of the meeting and subsequent papers was broad and included Neoproterozoic strata of the western U.S. and Siberia. In the preface to the first Belt Symposium Savage (1973) acknowledges A.C. Peale as "Founder" of Belt Geology and C.P. Ross as "Father" of Belt Geology. These men, and C.D. Walcott, who was first to sub–divide the Belt, were strong–willed field geologists who spent decades mapping this thick pile of thrust– faulted quartzite, siltite, and argillite. Because of the geographic extent and great thickness of the Belt Supergroup, years of work have been required before one's conclusions are "bona fide", and only a few have been able to pay their dues. A core of these geologists composes the non–profit Belt Association, founded in 1984 by officers Jack Harrison, Greg McKelvey, Jon Thorson, and Jim Whipple, and board members Dick Berg, Ian Lange, Chet Wallace, and Don Winston. Subsequent board members John Balla, Earl Bennett, Lisa Hardy, Nancy Joseph, David Kidder, David Lidke, and Brian White kept the Belt Association active through the 1980s and 1990s. Present board members Larry Appelgate, Art Bookstrom, Jim Browne, Reed Lewis, Paul

Abstract Latin america’s oil output (including the island of Trinidad ) was inferioronly to that of the United States for the period 1918-1949, exceeding the total of Europeby 1.5 billion barrels and all of Asia andAfrica by 3.6 billion. Its annual productionfell behind that of Europe temporarily in thedepression years 1931—1935 and war year1942, but was slightly greater than the aggregate of all countries except the United Statesin 1945 and 1946. It was not surpassed by theMiddle East until 1950. Production of the region in 1972 was 1,787 million barrels andthe cumulative was about 41 billion barrels. Sixteen oil fields in six Latin American nations are listed by Halbouty et al. (1970) asgiants of 500 million or more barrels; outstanding is Venezuela’s Bolivar Coastal field with estimated ultimate recovery of 30 billionbarrels, probably the third largest in the world. In the Latin countries, American oil companies had their first experience as foreign producers, and European companies met competition that sharpened their skills acquiredin the Eastern Hemisphere. Fortunes havebeen uneven; a few companies obtained verylarge production while many others with similar ability and opportunity achieved meageror negative results. Several seemingly favorableareas have failed to reward persistent andcostly prospecting. Two nations— Mexico and Brazil —have conducted large-scale nationalizedoil industries successfully. Most of the regionhas presented severe handicaps common to thetropics and subtropics—difficult terrain, uncomfortable climate, and hazards to health. Unstable political conditions have made foreign investments generally precarious. Exploration in Central and South America has beenan exciting adventure for the hardy breed of geologists

Abstract Few examples of ancient continental-sabkha evaporites have been recognized in the geologic record, despite the fact that numerous other continental-type deposits have been described. Furthermore, detailed sedimentological descriptions of Recent continental evaporites are also lacking. Work that has been done (Hardie et al., 1978) indicates that depositional processes and facies characteristics of Recent continental sabkhas are often similar to those of coastal sabkhas. Thus, it is quite possible that ancient continental-sabkha deposits do exist in the geologic record, but have been misidentified as marine in origin. In light of our limited knowledge of continental sabkha deposits, this report presents some sedimentological data and interpretations of Bristol Dry Lake, California (Fig. 1), a 155 km 2 continental-sabkha playa basin filled with at least 300 m of interbedded terrigenous clastics, gypsum, anhydrite, and halite (Bassett et al., 1959). Approximately 1-1/2 weeks of reconnaissance field work, supported by the Texas Bureau of Economic Geology and the U.S. Department of Energy, was conducted during 1979-80. Bristol Dry Lake is well suited for sedimentological studies because there are numerous trenches and pits dug by salt companies across the playa. Many of these are up to 6 m deep and expose intricate details of playa shallow-stratigraphy.