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ABSTRACT; Devonian Geology of Canada

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ABSTRACT; Devonian Geology of Canada ASSOCIATION ROL'M) TABLK 1899 least 95% of the uranium reserves in Wyoming, Wyo­ TRIASSIC-JURASSIC OF ALBERTA, SASKATCHEWAN, ming reserves were estimated by the AEC at 53,270 MANITOBA, MONTANA, AND NORTH DAKOTA tons of UaOs as of January 1, 1967. Distribution of Of the Triassic-Jurassic Systems, only Lower Trias- reserves in tons of U.IOB together with production to sic was deposited in southern Saskatchewan, North January 1, 1967 are estimated as follows: Gas Hills, Dakota, and southern Montana. Thicknesses in excess 19,560± tons reserve, 17,300 tons produced; Shirley of 700 ft are present in western North Dakota basin, 27,000± tons reserve, 3,450 tons produced; reflecting the depocenter of restricted salt basins. On Crooks Gap, 4,000± tons reserve, 2,400 tons produced; the basis of lithologic correlation, the lower Watrous other Tertiary basins including Powder River, 1,000± Formation in Saskatchewan is considered to be equiv­ tons reserve, 1,100 tons produced. alent to the upper part of the Spearfish Formation in Wind River and equivalent rocks crop out in broad North Dakota. Lower Middle and Upper Triassic areas within the intermontane Tertiary basins of cen­ rocks in western Alberta are of marine origin, attain tral Wyoming. The sediments that comprise these thicknesses in excess of 4,000 ft, and produce oil and lower Eocene beds were derived from mountain gas. ranges that were upUfted during Late Cretaceous Jurassic rocks are widespread throughout the map through earliest Eocene times. Two fades predomi­ area as a result of Jurassic seas transgressing from the nate within the major basins. A coarse arkosic sand­ northwest along the Eastern Cordillera, then spread­ stone and conglomerate facies with interbedded silt- ing east across Montana into the Williston basin. stone dominates near the mountain fronts. Major Lower Jurassic formations in the map area are re­ uranium deposits occur in this facies. Farther out in stricted to southwestern Alberta. Middle Jurassic for­ the basins the coarse-grained sediments grade into or mations are the most widespread, and are thicker than interfinger with a variegated fine-grained facies. 500 ft in a depocenter in southeast Saskatchewan and Economic concentrations of uranium occur near the northwest North Dakota. Similar thicknesses are pres­ margins of tongues of altered sandstone within the ent in the Alberta trough. Upper Jurassic sediments coarse-grained facies and are classified as roll-type also are widespread, reaching thicknesses of 7,OCX! ft in deposits. Character of alteration differs from basin to the Eastern Cordillera of Alberta and more than 700 basin but has been recognized to some degree in all ft in eastern Montana. basins. Alteration consists of the oxidation products Economic deposits of coal, gypsum, oil, and gas produced by mineralized ground water passing occur in Middle and Upper Jurassic formations. Oil is through a transmissive sandstone bed. Geometrically the most significant, particularly in southwestern Sas­ the deposits are tongue-shape in plan and crescent- katchewan where 20 fields are estimated to have ulti­ shape in vertical section with the concave side toward mate production of 347 million bbl. These fields pro­ the altered sandstone. duce in stratigraphic traps, primarily from sandstone Deposition of uranium occurred at the front of an associated with shoreline facies. advancing aqueous chemical system which moved through the host sandstone bed. The oxygenated water rich in uranium, selenium, and other trace ele­ N. JAMES CLINTON, Lockheed Electronics Co., ments moved along the hydrologic gradient and oxi­ Houston, Texas dized and leached various minerals, including urani­ GEOLOGY or THE MOON um, as it progressed. Precipitation of the uranium and At present, most knowledge of detailed geologic associated elements occurred at a point within the conditions on the moon is limited geographically to aquifer where the pH and Eh of the system dropped the photographic missions of the Lunar Orbiter pro­ sharply. The change in chemical environment was the gram which has primarily covered the Apollo Zone. result of the presence of HsS, probably produced by Complications caused by albedo, high sun elevations, anaerobic bacteria. and electronic imagery distortion hamper photo inter­ pretation. AN ASTRONAUT The lunar stratigraphy is divided into four systems: (No abstract submitted) pre-Imbrian-highlands ringing the oldest mare; Im- brian—the oldest lowland mare; Eratosthenian— PAUL AVERITT, U. S. Geol. Survey Fuels Branch, "eroded" crater material; and Copernicus-recent cra­ Denver, Colorado ter material. FUTURE ROLE OF ROCKY MOUNTAIN COAL Ubiquitous craters appear to be formed by both im­ pact of meteors and volcanic activity. Faults, slump (No abstract submitted) or creep, flowage—all appear to be present on the THOMAS D. BARROW, Humble Oil Co., Houston, lunar surface. Synoptic orbital photography of the earth is a logi­ Texas cal outgrowth of the lunar program. Use of synoptic KEYNOTE ADDRESS photography will improve exploration geologists' un­ (No abstract submitted) derstanding of their individual areas of interest as they relate to the regional geologic setting. GORDON BASSETT, Shell Oil Co. of Canada, Ltd., Geologic processes and theories developed on earth Edmonton, Alberta, AND JOHN STOUT, Chevron will aid the interpretation of morphological and struc­ Oil Co., Denver, Colorado tural conditions on the moon. Likewise, technologies DEVONIAN GEOLOGY or CANADA, MONTANA, AND WYO­ developed from the lunar and planetary program will MING aid exploration on the earth. (No abstract submitted) H. F. COFFER, CER Geonuclear Corporation, Las C. E. CARLSON, Mobil Oil Canada, Ltd., Calgary, Vegas, Nevada, H. E. GRIER, AND H. H. ARONSON Alberta, AND H. A. GIBSON, Mobil Oil Company, USE OF NUCLEAR EXPLOSIVES IN OIL AND GAS PRO­ Casper, Wyoming DUCTION .
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