干旱区生态环境知识资源中心(Arid): ER-12-1 completion report

Arid

DOI	10.2172/465859
报告编号	DOE/NV/10845--36; DRI--45120
来源ID	OSTI_ID: 465859
	ER-12-1 completion report
	Russell, C.E.; Gillespie, D.; Cole, J.C.; Drellack, S.L. [and others]
英文摘要	The objective of drillhole ER-12-1 was to determine the hydrogeology of paleozoic carbonate rocks and of the Eleana Formation, a regional aquitard, in an area potentially downgradient from underground nuclear testing conducted in nearby Rainier Mesa. This objective was addressed through the drilling of well ER-12-1 at N886,640.26 E640,538.85 Nevada Central Coordinates. Drilling of the 1094 m (3588 ft) well began on July 19, 1991 and was completed on October 17, 1991. Drilling problems included hole deviation and hole instability that prevented the timely completion of this borehole. Drilling methods used include rotary tri-cone and rotary hammer drilling with conventional and reverse circulation using air/water, air/foam (Davis mix), and bentonite mud. Geologic cuttings and geophysical logs were obtained from the well. The rocks penetrated by the ER-12-1 drillhole are a complex assemblage of Silurian, Devonian, and Mississippian sedimentary rocks that are bounded by numerous faults that show substantial stratigraphic offset. The final 7.3 m (24 ft) of this hole penetrated an unusual intrusive rock of Cretaceous age. The geology of this borehole was substantially different from that expected, with the Tongue Wash Fault encountered at a much shallower depth, paleozoic rocks shuffled out of stratigraphic sequence, and the presence of an altered biotite-rich microporphyritic igneous rock at the bottom of the borehole. Conodont CAI analyses and rock pyrolysis analyses indicate that the carbonate rocks in ER-12-1, as well as the intervening sheets of Eleana siltstone, have been thermally overprinted following movement on the faults that separate them. The probable source of heat for this thermal disturbance is the microporphyritic intrusion encountered at the bottom of the hole, and its age establishes that the major fault activity must have occurred prior to 102.3+0.5 Ma (middle Cretaceous).
出版年	1996
报告类型	Technical Report
语种	英语
国家	美国
来源学科分类	45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE ; 54 ENVIRONMENTAL SCIENCES ; NEVADA TEST SITE ; BOREHOLES ; GEOLOGIC FORMATIONS ; HYDROLOGY
URL	http://www.osti.gov/scitech/servlets/purl/465859
资源类型	科技报告
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/266792
推荐引用方式 GB/T 7714	Russell, C.E.,Gillespie, D.,Cole, J.C.,et al. ER-12-1 completion report,1996.