| Abstract: | Uranium and thorium are concentrated in Cretaceous limestone, chert, ash, basalt, and other rock types at Deep Sea Drilling Project Site 465 located on the southern Hess Rise in the central North Pacific. U concentrations, up to 194 ppm on a carbonate-free basis, are among the highest recorded for any deep-sea deposits. U was initially derived from seawater and concentrated by absorption on terrigenous (humic) organic matter in limestone in a shallow marine environment. U and Th were probably concentrated further by low-temperature hydrothermal fluids emanating from the basaltic basement. Mainly montmorillonite, an alteration product of basalt and ash, and organic matter in sedimentary rocks acted as hosts for U and Th. The unique combination of sediments rich in humic organic matter, abundant smectite in altered ash and basalt, and warm hydrothermal solutions provided the necessary conditions for migration and concentration of U and Th. To better understand the conditions limiting the migrating and concentration of U and Th, other rocks deposited during the ocean-wide Cretaceous anoxic events should be analyzed for these elements. ?? 1982. |
| Genre: | Article |
| ProdID: | 70011912 |
| Citation Author: | Hein, J. R.; Koski, R. A.; Morgenson, L. A. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 251 |
| Citation Issue: | 3-4 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Chemical Geology |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 15 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | Elsevier |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Uranium and thorium enrichment in rocks from the base of DSDP Hole 465A, Hess Rise, central North Pacific; 1982; Article; Journal; Chemical Geology; Hein, J. R.; Koski, R. A.; Morgenson, L. A. |
| Citation Start Page: | 237 |
| Citation Volume: | 36 |
| Citation Year: | 1982 |
| Type: | citation/reference |
| Text: | Uranium and thorium enrichment in rocks from the base of DSDP Hole 465A, Hess Rise, central North Pacific; 1982; Article; Journal; Chemical Geology; Hein, J. R.; Koski, R. A.; Morgenson, L. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/0009-2541(82)90050-X |
| Date Other: | Fri, 1 Jan 1982 00:00 -0600 |
| Publisher: | Elsevier |
