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您的检索式：作者名="Rankenburg"
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| 1 | The role of continental crust and lithospheric mantle in the genesis of Cameroon Volcanic Line lavas:constraints from isotopic variations in lavas and megacrysts from the Biu and Jos Plateau显示文摘 | Rankenburg K Lassiter J.C Brey G | | 0，，： | 1 |
| 2 | Searching with iterated maps显示文摘 | Elser V Rankenburg I and Thibault P | 2007 | Proceedings of the National Academy of Sciences2007，104，2： | 1 |
| 3 | Neodymium isotope evidence for a chondritic composition of the Moon显示文摘 | Rankenburg K Brandon A D Neal C R | 2006 | Science2006，312，： | 1 |
| 4 | Neodymium isotope evidence for a chondritic composition of the Moon显示文摘 | Rankenburg K Brandon A D Neal C R | 2006 | Sci- ence2006，312，： | 1 |
| 5 | Granular titanite from the Roter Kamm crater in Namibia:Product of regional metamorphism,not meteorite impact显示文摘Accessory minerals with so-called granular texture have risen in importance as geochronological tools for U-Pb dating of meteorite impact events. Grain-scale recrystallization, typically triggered by a combination of high-strain deformation and post-impact heating, can create a polycrystalline microstructure consisting of neoblasts that expel radiogenic Pb, which are thus ideal for isotopic dating. While granular domains in zircon and monazite from shocked rocks have been demonstrated to preserve impact ages,few U-Pb dating studies have been conducted on granular microstructures in titanite(CaTiSiO;). Here we report the occurrence of granular-textured titanite from ~2020 Ma granite basement rock exposed in the rim of the 4–5 Ma Roter Kamm impact structure in Namibia. Orientation mapping reveals two microstructurally distinct titanite populations: one consisting of strained/deformed grains, and the other consisting of grains that comprise aggregates of strain-free neoblasts. In situ U-Pb geochronology on 37 grains shows that most grains from both titanite populations yield indistinguishable U-Pb dates of ca.1025 Ma, consistent with the observed microstructures forming during the Mesoproterozoic Namaqua Orogeny. Only four grains preserved older age domains, recording ca. 1875 Ma Paleoproterozoic metamorphism. Two significant observations emerge:(1) none of the analyzed titanite grains yield the 2020 Ma igneous crystallization age previously established from zircon in the same sample, and(2) no age-resetting was detected that could be attributed to the 4 to 5 Ma Roter Kamm impact event.Despite the similarity of the neoblastic microstructure to minerals from other sites with an established impact provenance, the granular texture and near-complete Pb-loss in titanite from Roter Kamm granite instead records a Paleo-to Mesoproterozoic polymetamorphic history, rather than Miocene age shockrelated processes. These results highlight the critical importance of grain-scale context for interpretation of U-Pb data in granular titanite, and the potential for misinterpreting inherited(pre-impact) microstructures as impact-related phenomenon in target rocks with a complex geological history. | Aaron J.Cavosie Christopher J.Spencer Noreen Evans Kai Rankenburg Robert J.Thomas Paul H.Macey | 2022 | Geoscience Frontiers2022，13，3： | 0 |
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