Abstract
impact on their diagnostic trace element ratios. Much stronger Continental flood basalts (CFBs) of Jurassic age make up the overprint, in the CT1 and CT2 suites, resulted from contamination Vestfjella mountains of western Dronning Maud Land and demwith veined Archaean lithospheric mantle, which produced wide onstrate an Antarctic extension of the Karoo large igneous province. ranges of isotopic and highly incompatible element ratios. CT3, in A detailed geochemical study of the 120-km-long Vestfjella range turn, does not show evidence of interaction with the Proterozoic shows the CFB suite to consist mainly of three intercalated basaltic lithospheric mantle. The highNd endmembers of CT1, CT2 rock types designated CT1, CT2 and CT3 (chemical types 1, 2 and CT3 probably closely resemble uncontaminated mantle-derived and 3) that exhibit different incompatible trace element ratios. CT1 magmas and indicate three different mantle sources. The CT2 and CT2 of north Vestfjella record wide ranges of Nd and Sr primary magmas were derived from light rare earth element (LREE)isotopic compositions with initial Nd and Sr ranging from +7·6 depleted, slightly large ion lithophile element (LILE)-enriched to −16·0 and −16 to +65, respectively. The southern Vestfjella sources, whereas data on the volumetrically preponderant CT1 and is dominated by CT3 with near-chondritic Nd (+2·0 to −4·1) CT3 point to variably LREE-enriched, strongly LILE-enriched and Sr (−11 to +19). A volumetrically minor suite of ocean sources. The sources of CT1, CT2 and CT3 may record largeisland basalt (OIB-)like CT4 dykes ( Nd +3·6, Sr +1) cuts scale lateral heterogeneity generated by subduction-contamination of the lava sequence in north Vestfjella. The pronounced isotopic the Gondwanan upper mantle. The OIB-like CT4 dykes probably differences suggest different magmatic plumbing systems for the reflect asthenospheric heterogeneities that were unrelated to the heterogeneous CT1 and CT2 suites and the relatively homogeneous proposed subduction-contamination. CT3 lavas. This is further supported by the palaeoflow directions, which point to major source regions to the north (CT1 and CT2) and east (CT3) of Vestfjella. These source regions can be associated with two contemporaneous major lithospheric thinning zones that
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
