Blar i forfatter Artikler, rapporter og annet (geovitenskap) "Tappe, Sebastian"

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    • Calcium isotopes track volatile components in the mantle sources of alkaline rocks and associated carbonatites 

      Chen, Chunfei; Foley, Stephen F.; Tappe, Sebastian; Ren, Huange; Feng, Lanping; Liu, Yongsheng (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-16)
      The volatile components CO2 and H2O induce mantle melting and thus exert major controls on mantle heterogeneity. Primitive intraplate alkaline magmatic rocks are the closest analogues for incipient mantle melts and provide the most direct method to assess such mantle heterogeneity. Given the considerable Ca isotope differences among carbonate, clinopyroxene, garnet, and orthopyroxene in the mantle ...

    • Evolution of ultrapotassic volcanism on the Kaapvaal craton: deepening the orangeite versus lamproite debate 

      Tappe, Sebastian; Shaikh, Azhar M.; Wilson, Allan H.; Stracke, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-02)
      Orangeites are a significant source of diamonds, yet ambiguity surrounds their status among groups of mantle-derived potassic rocks. This study reports mineralogical and geochemical data for a c. 140 Ma orangeite dyke swarm that intersects the Bushveld Complex on the Kaapvaal craton in South Africa. The dykes comprise distinctive petrographic varieties that are linked principally by olivine ...

    • The Paleoarchean Buffalo River komatiites: Progressive melting of a single large mantle plume beneath the growing Kaapvaal craton 

      Netshidzivhe, Thendo; Tappe, Sebastian; Wilson, Allan H.; Ishikawa, Akira; Viljoen, Fanus (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-01)
      Several Archean granitoid-greenstone terranes are exposed on the southeastern Kaapvaal craton in South Africa, but they received little scientific attention compared to the archetypal greenstone belt successions of the Barberton Mountain Land at the eastern craton margin. This study reports on a detailed field and geochemical survey of the Buffalo River Greenstone Belt at the southern Kaapvaal craton ...

    • Plume–lithosphere interactions and LIP-triggered climate crises constrained by the origin of Karoo lamproites 

      Tappe, Sebastian; Ngwenya, Ntando S.; Stracke, Andreas; Romer, Rolf L.; Glodny, Johannes; Schmitt, Axel K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-20)
      We identified a ca. 180 Ma diamondiferous lamproite event in Zambia, establishing a link between ultrapotassic volcanism and the early Jurassic Karoo flood basalt province of sub-Saharan Africa. The cratonic lamproites erupted through the Permo–Triassic Luangwa Rift structure, but MgO-rich ultrapotassic magma formation was unrelated to rifting and triggered by plume–lithosphere interactions during ...

    • Redox state of the Dharwar craton root as inferred from eclogite and peridotite sourced mantle cargo, with implications for kimberlite and lamproite magma formation 

      Shaikh, Azhar M.; Bussweiler, Yannick; Viljoen, Fanus; Bolhar, Robert; Ravi, S.; Hezel, Dominik C.; Ueckermann, Henriëtte; Tappe, Sebastian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-16)
      Despite over 400 occurrences of kimberlites and related rocks in India, mantle-derived xenoliths are known only from a few occurrences. This paucity of mantle-derived xenoliths in Indian kimberlites has hampered investigations of the subcontinental lithospheric mantle (SCLM). Using a valuable selection of the rare xenolith inventory, we here report Fe<sup>3+</sup>/ΣFe measurements for garnets using ...

    • Sheared Peridotite and Megacryst Formation Beneath the Kaapvaal Craton: A Snapshot of Tectonomagmatic Processes across the Lithosphere-Asthenosphere Transition 

      Tappe, Sebastian; Massuyeau, Malcolm; Smart, Katie A; Woodland, Alan B; Gussone, Nikolaus; Milne, Sarah; Stracke, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-27)
      The cratonic lithosphere–asthenosphere boundary is commonly invoked as the site of sheared peridotite and megacryst formation, a well-recognized petrological assemblage whose genetic relationships—if any—remain poorly understood. We have undertaken a comprehensive petrology and Sr–Nd–Hf–Ca isotope study of sheared peridotite xenoliths and clinopyroxene megacrysts from the c. 1150 Ma Premier kimberlite ...

    • Tracing Subducted Carbonates in Earth's Mantle Using Zinc and Molybdenum Isotopes 

      Wang, Jian; Tang, Gong-Jian; Tappe, Sebastian; Li, Jie; Zou, Zongqi; Wang, Qiang; Su, Yu-Ping; Zheng, Jian-Ping (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-23)
      Although carbonates are the primary form of carbon subducted into the mantle, their fate during recycling is debated. Here we report the first coupled high-precision Zn and Mo isotope data for Cenozoic intraplate basalts from western China. The exceptionally high δ<sup>66</sup>Zn values (+0.39 to +0.50‰) of these lavas require involvement of recycled carbonates in the mantle source. Variable ...