PANGAEA_696416 (Table 1) Chemical and lithological composition of rocks from DSDP Hole 465A Hein, James R; Koski, Randolph A; Morgenson, Lisa A (Table 1) Chemical and lithological composition of rocks from DSDP Hole 465A 1982 PANGAEA Dataset Supplement to: Hein, James R; Koski, Randolph A; Morgenson, Lisa A (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 https://doi.pangaea.de/10.1594/PANGAEA.696416 Investigator James R Hein jhein@usgs.gov Earth Science DEPTH, sediment/rock Sample code/label Rock type Lithology/composition/facies Minerals Silicon dioxide Aluminium oxide Titanium dioxide Iron oxide, Fe2O3 Magnesium oxide Calcium oxide Sodium oxide Potassium oxide Phosphorus pentoxide Barium oxide Sulfite Manganese Loss on ignition Sum Carbon, organic, total Calcium carbonate Uranium Thorium geoscientificInformation 62-465A Drilling/drill rig Leg62 DSDP/ODP/IODP sample designation X-ray fluorescence on pressed powder Calculated Element analyser CHN, LECO WR-12 Element analysis, neutron activation (NAA) Glomar Challenger 1978-08-23 1978-08-23 Complete 33.8205 33.8205 178.919 178.919 392.8 m (DEPTH, sediment/rock) 419.5 m (DEPTH, sediment/rock) DSDP Deep Sea Drilling Project unrestricted CC-BY-3.0: Creative Commons Attribution 3.0 Unported English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

Leobener Str.

Bremen Bremen 28359 Germany online 278 data points text/tab-separated-values

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. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.696416"! ** 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.

http://en.wikipedia.org/wiki/Loss_on_ignition Loss on ignition http://www.deepseadrilling.org/ DSDP https://doi.org/10.1016/0009-2541(82)90050-X Uranium and thorium enrichment in rocks from the base of DSDP Hole 465A, Hess Rise, Central North Pacific https://en.wikipedia.org/wiki/Calcium_oxide Calcium oxide https://en.wikipedia.org/wiki/Silicon_dioxide Silicon dioxide https://en.wikipedia.org/wiki/Sulfite Sulfite https://en.wikipedia.org/wiki/Titanium_dioxide Titanium dioxide https://hdl.handle.net/10013/epic.27914.d001 DSDP/ODP/IODP sample designation https://www-odp.tamu.edu:443/glomar.html Glomar Challenger DIF 9.4 2026-05-01