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CC-BY - Uznanie autorstwaTholeiitic- and boninite-series metabasites of the Nové Město Unit and northern part of the Zábřeh Unit (Orlica–Śnieżnik Dome, Bohemian Massif) : petrogenesis and tectonic significance
| cris.lastimport.scopus | 2024-02-12T20:38:56Z |
| dc.abstract.en | The Nové Město Unit and the northern part of the Zábřeh Unit comprise back-arc basin mafic rocks metamorphosed during Variscan times. In both units, nearly identical metabasites comprise variously enriched tholeiites (from N-MORB to transitional E-MORB-OIB), high-Ca, low-silica boninites and low-Ti tholeiites. The tholeiites (Ti/V: 22–58, εNd<sub>540</sub>: + 7.6 to − 4.7) represent 10–15% melting at ca. 30–60 km and temperatures of 1380–1230 °C of a depleted MORB mantle-type (DMM) wedge heterogeneously modified shortly before fusion by OIB-like melts (enriched mantle possibly of EM1–EM2 type) presumably derived from decompression melting of upwelling asthenosphere. Much less common meta-boninites (Ti/V: 6–23, εNd<sub>540</sub>: + 6.7 to − 2.9) formed by 15–25% re-melting of residual mantle (DMM after ~ 15% melt extraction) at depths of 40–65 km and temperatures of ~ 1420–1300 °C. Scarce low-Ti meta-tholeiites (Ti/V: 18–19, εNd<sub>540</sub>: + 7.1) resulted from < 10% melting of an unenriched DMM-type source or re-melting of residual mantle (after < 15% of former melting). Trace elements and Nd isotope compositions imply random fluxing of tholeiitic- and boninitic magma sources by components released from a subducted slab. The metasomatic enrichment (Th, LREE–MREE) was induced not only by sediment-derived melts but also by fluids supplied by subducted sediments or juvenile crust. The Nové Město–Zábřeh association of metabasites points to an easterly prolongation (in present-day coordinates) of the Cadomian subduction system of the Teplá–Barrandian. Boninite-type magmatism and OIB-like input into mantle beneath an extensional back-arc basin suggest an upflow of hot asthenosphere through subducted ridge (slab window) followed by a cessation of subduction zone activity. |
| dc.affiliation | Uniwersytet Warszawski |
| dc.contributor.author | Pin, Christian |
| dc.contributor.author | Ilnicki, Sławomir |
| dc.contributor.author | Szczepański, Jacek |
| dc.date.accessioned | 2024-01-26T10:52:07Z |
| dc.date.available | 2024-01-26T10:52:07Z |
| dc.date.copyright | 2020-04-03 |
| dc.date.issued | 2020 |
| dc.description.accesstime | AT_PUBLICATION |
| dc.description.finance | Publikacja bezkosztowa |
| dc.description.number | 4 |
| dc.description.version | FINAL_PUBLISHED |
| dc.description.volume | 109 |
| dc.identifier.doi | 10.1007/S00531-020-01845-5 |
| dc.identifier.issn | 1437-3254 |
| dc.identifier.uri | https://repozytorium.uw.edu.pl//handle/item/123348 |
| dc.identifier.weblink | http://dx.doi.org/10.1007/s00531-020-01845-5 |
| dc.language | eng |
| dc.pbn.affiliation | earth and related environmental sciences |
| dc.relation.ispartof | International Journal of Earth Sciences |
| dc.relation.pages | 1247-1271 |
| dc.rights | CC-BY |
| dc.sciencecloud | nosend |
| dc.subject.en | Tholeiites |
| dc.subject.en | Boninites |
| dc.subject.en | Trace elements |
| dc.subject.en | Nd isotopes |
| dc.subject.en | Back-arc basin |
| dc.title | Tholeiitic- and boninite-series metabasites of the Nové Město Unit and northern part of the Zábřeh Unit (Orlica–Śnieżnik Dome, Bohemian Massif) : petrogenesis and tectonic significance |
| dc.type | JournalArticle |
| dspace.entity.type | Publication |