| Abstract: | Stable-isotope compositions of fracture- and cavity-filling calcite from the unsaturated zone of three drill cores at Yucca Mountain Tertiary volcanic complex indicate that the water from which the minerals precipitated was probably meteoric in origin. A decrease in 18O in the calcite with depth is interpreted as being due to the increase in temperature in drill holes corresponding to an estimated average geothermal gradient of 34?? per kilometer. A few of the calcite samples and all of the opal samples yielded uranium-series ages older than 400 000 yr, although most of the calcite samples yielded ages between 26 000 and 310 000 yr. The stable-isotope and uranium-series dates from precipitated calcite and opal of this reconnaissance study suggest a complex history of fluid movement through the volcanic pile, and episodes of fracture filling predominantly from meteoric water during at least the past 400 000 yr. -Authors |
| Genre: | Article |
| ProdID: | 70016109 |
| Citation Author: | Szabo, B. J.; Kyser, T. K. |
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| Citation End Page: | 1719 |
| Citation Issue: | 12 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geological Society of America Bulletin |
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| Citation Number Of Pages: | 6 |
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| Citation Search Results Text: | Ages and stable-isotope compositions of secondary calcite and opal in drill cores from Tertiary volcanic rocks of the Yucca Mountain area, Nevada; 1990; Article; Journal; Geological Society of America Bulletin; Szabo, B. J.; Kyser, T. K. |
| Citation Start Page: | 1714 |
| Citation Volume: | 102 |
| Citation Year: | 1990 |
| Type: | citation/reference |
| Text: | Ages and stable-isotope compositions of secondary calcite and opal in drill cores from Tertiary volcanic rocks of the Yucca Mountain area, Nevada; 1990; Article; Journal; Geological Society of America Bulletin; Szabo, B. J.; Kyser, T. K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1990 00:00 -0600 |
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