HR: 1340h
AN: V43E-1465    [Abstracts]
TI: Geochemical And Petrological Investigations Of The Representative Cretaceous Bentonite Beds, Wyoming : Tectonic Implications
AU: * KHANDAKER, N I
EM: kdaker@york.cuny.edu
AF: YORK COLLEGE OF CUNY, DEPARTMENT OF NATURAL SCIENCES 94-20 GUY R. BREWER BLVD., JAMAICA, NY 11451
AB: Representative bentonite samples were collected from the exposed Cretaceous siliciclastics in Bighorn Basin, north-central Wyoming. Bentonite beds constitute a significant stratigraphic importance with respect to local and regional correlation tool and are associated with the Thermopolis Shale (Lower Cretaceous), Mowry Shale (Lower Cretaceous), and Frontier Formation (Upper Cretaceous). These beds range in thickness from few inches to ten feet and are interbedded with thick cross-bedded sandstone, pebbly sandstone, polymictic conglomerate, siliceous-rippled shale, and lignitic shale. Preliminary petrological and geochemical investigations were carried out to establish a distinctive geochemical signature for each bed. Emphasis was given on the overall distribution of the immobile traces, high refractory elements, and ultrastable heavy mineral components among the selective bentonite beds. The outcome of petrological, bulk, and trace element studies involving multiple bentonite beds indicated a subtle difference in terms of abundance of trace-element and detrital components among the studied samples and can be attributed to the source region characteristics, distinctive diagenetic pathways, and depositional setting. Furthermore, geochemical analyses involving multi-element plots suggest to an evolving source terrain located in close proximity to the bentonite depositional basin.
DE: 8110 Continental tectonics--general (0905)
DE: 3670 Minor and trace element composition
DE: 1749 Volcanology, geochemistry, and petrology
DE: 1815 Erosion and sedimentation
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting