Spence porphyry copper deposit: Hematite (U-Th-Sm)/He geochronology
This spreadsheet contains (U-Th-Sm)/He data for 73 hematite samples from the supergene profile of the Spence porphyry copper deposit in the Central Andes. These data are discussed in the G-cubed publication titled 'A rusty record of weathering and groundwater movement in the hyperarid Central Andes' (Shaw et al., 2021). Spence porphyry copper deposit Drill hole SPD0324, UTM WGS1984 19S, E 474975.22, N 7481100.39 Drill hole SPD 1848, UTM WGS1984 19S, E 474998.29, N 7481399.87 Drill hole SPD 0402, UTM WGS1984 19S, E 473969.87, N 7479755.01
dataset
https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item167044
name: Data
function: download
http://data.bgs.ac.uk/id/dataHolding/13607774
eng
Royal Society Research Grant RG140683
geoscientificInformation
publication
2008-06-01
Helium
Uranium
Porphyry copper deposits
Weathering
NGDC Deposited Data
Thorium
Geochronology
Samarium
revision
2022
NERC_DDC
-69.5000
-69.0000
-22.5400
-22.9400
creation
1979
ANDES [id=842000]
2017-01-02
2019-03-29
creation
2021-06-25
notApplicable
(U-Th-Sm)/He dating was done at Caltech, using the single aliquot method (Farley, 2002; House et al., 2000). Hematite fragments were loaded into Pt tubes and degassed by incremental heating with a Nd-YAG laser to >1000⁰ C. He extraction conducted under high pO2 (100 torr), buffering the hematite-magnetite transition to >1200° C (Hofmann et al., 2020). Isotope-dilution measurements of 4He were made with an enriched 3He spike, using a Pfeiffer Vacuum quadrupole mass spectrometer. U, Th and Sm were measured on the same aliquots using an Agilent 8800 triple-quadrupole ICP-MS (e.g. Hofmann et al., 2017). (U-Th-Sm)/He ages were calculated according to Farley (2002). Since aliquots were taken from structures much larger than the typical alpha-particle stopping distance in hematite of 13-16 µm (Ketcham et al., 2011), no correction for alpha-ejection or -implantation was applied.
publication
2011
false
See the referenced specification
publication
2010-12-08
false
See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF
MS Excel
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