| Autor: |
Esther Scheiblhofer, Ulrike Moser, Stefan Lӧhr, Markus Wilmsen, Juraj Farkaš, Daniela Gallhofer, Alice Matsdotter Bäckström, Thomas Zack, Andre Baldermann |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
Minerals, Vol 12, Iss 7, p 818 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2075-163X |
| DOI: |
10.3390/min12070818 |
| Popis: |
The scarcity of well-preserved and directly dateable sedimentary sequences is a major impediment to inferring the Earth’s paleo-environmental evolution. The authigenic mineral glauconite can potentially provide absolute stratigraphic ages for sedimentary sequences and constraints on paleo-depositional conditions. This requires improved approaches for measuring and interpreting glauconite formation ages. Here, glauconite from a Cretaceous shelfal sequence (Langenstein, northern Germany) was characterized using petrographical, geochemical (EMP), andmineralogical (XRD) screening methods before in situ Rb-Sr dating via LA-ICP-MS/MS. The obtained glauconite ages (~101 to 97 Ma) partly overlap with the depositional age of the Langenstein sequence (±3 Ma), but without the expected stratigraphic age progression, which we attribute to detrital and diagenetic illitic phase impurities inside the glauconites. Using a novel age deconvolution approach, which combines the new Rb-Sr dataset with published K-Ar ages, we recalculate the glauconite bulk ages to obtain stratigraphically significant ‘pure’ glauconite ages (~100 to 96 Ma). Thus, our results show that pristine ages can be preserved in mineralogically complex glauconite grains even under burial diagenetic conditions (T < 65 °C; |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
|
|
Nepřihlášeným uživatelům se plný text nezobrazuje |
K zobrazení výsledku je třeba se přihlásit.
|
