| Autor: |
J. Stephen Daly, Foteini Drakou, John Murray, Paul C. Guyett, Eszter Badenszki, Brendan C. Hoare, Aodhán Ó'Gogáin, David Chew, Gary O'Sullivan |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
Sedimentary Geology. 422:105961 |
| ISSN: |
0037-0738 |
| DOI: |
10.1016/j.sedgeo.2021.105961 |
| Popis: |
Sedimentary phosphates, chiefly composed of apatite group minerals, contain exceptionally high concentrations (10–200 ppm) of U relative to other sedimentary precipitates, making them an attractive target for U–Pb dating. Phosphate-rich sedimentary rocks are common from the Neoproterozoic onwards and commonly occur at key points in the geological record, often coinciding with periods of significant environmental flux or facies change. There is thus a clear rationale for dating phosphatic rocks. In this study, we demonstrate how spatially-resolved U–Pb dating of sedimentary apatite by laser-ablation quadrupole inductively-coupled-plasma mass-spectrometry (LA-Q-ICPMS) can provide constraints on early phosphate diagenesis and reworking in ancient rocks. Our samples are from two locations in a well-characterized stratigraphic sequence containing phosphorites, and phosphate-rich carbonates and shales in western Ireland, which span the Mississippian–Pennsylvanian (mid-Carboniferous) boundary. Sedimentary phosphate preserves precise ( |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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