Hein, James R; Koski, Randolph A; Morgenson, Lisa A (1982): (Table 1) Chemical and lithological composition of rocks from DSDP Hole 465A [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.696416, Supplement to: Hein, JR et al. (1982): Uranium and thorium enrichment in rocks from the base of DSDP Hole 465A, Hess Rise, Central North Pacific. Chemical Geology, 36(3-4), 237-251, https://doi.org/10.1016/0009-2541(82)90050-X
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Published: 1982 (exact date unknown) • DOI registered: 2008-08-05
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.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Latitude: 33.820500 * Longitude: 178.919000
Date/Time Start: 1978-08-23T00:00:00 * Date/Time End: 1978-08-23T00:00:00
Minimum DEPTH, sediment/rock: 392.80 m * Maximum DEPTH, sediment/rock: 419.50 m
Event(s):
62-465A * Latitude: 33.820500 * Longitude: 178.919000 * Date/Time: 1978-08-23T00:00:00 * Elevation: -2161.0 m * Penetration: 476 m * Recovery: 98.9 m * Location: North Pacific/CONT RISE * Campaign: Leg62 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 43 cores; 408.5 m cored; 9.5 m drilled; 24.2 % recovery
Comment:
In the sample 465A-40-1, 145 (calcareous ash / sulfide-rich fraction) contents of major oxides were measured by quantitative emission spectroscopy; in the samples 465A-40-2, 62 (altered ash) and 465A-40-2, 62 (altered ash, <1 µm fraction) contents of major oxides were measured by semi-quantitative emission spectroscopy.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
| 2 | Sample code/label | Sample label | Hein, James R | DSDP/ODP/IODP sample designation | ||
| 3 | Rock type | Rock | Hein, James R | |||
| 4 | Lithology/composition/facies | Lithology | Hein, James R | |||
| 5 | Minerals | Minerals | Hein, James R | major | ||
| 6 | Minerals | Minerals | Hein, James R | moderate | ||
| 7 | Minerals | Minerals | Hein, James R | minor | ||
| 8 | Minerals | Minerals | Hein, James R | trace | ||
| 9 | Silicon dioxide | SiO2 | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 10 | Aluminium oxide | Al2O3 | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 11 | Titanium dioxide | TiO2 | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 12 | Iron oxide, Fe2O3 | Fe2O3 | % | Hein, James R | X-ray fluorescence on pressed powder | total Fe as Fe2O3 |
| 13 | Magnesium oxide | MgO | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 14 | Calcium oxide | CaO | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 15 | Sodium oxide | Na2O | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 16 | Potassium oxide | K2O | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 17 | Phosphorus pentoxide | P2O5 | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 18 | Barium oxide | BaO | % | Hein, James R | X-ray fluorescence on pressed powder | |
| 19 | Sulfite | [SO3]2- | % | Hein, James R | 3 by difference on barite-rich samples | |
| 20 | Manganese | Mn | mg/kg | Hein, James R | X-ray fluorescence on pressed powder | |
| 21 | Loss on ignition | LOI | % | Hein, James R | at 1050°C | |
| 22 | Sum | Sum | % | Hein, James R | Calculated | |
| 23 | Carbon, organic, total | TOC | % | Hein, James R | Element analyser CHN, LECO WR-12 | |
| 24 | Calcium carbonate | CaCO3 | % | Hein, James R | Element analyser CHN, LECO WR-12 | |
| 25 | Uranium | U | mg/kg | Hein, James R | Element analysis, neutron activation (NAA) | |
| 26 | Thorium | Th | mg/kg | Hein, James R | Element analysis, neutron activation (NAA) | differences in detection limits are due to dilutions required to complete the analysis |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
278 data points