Matches in SemOpenAlex for { <https://semopenalex.org/work/W3171562554> ?p ?o ?g. }
- W3171562554 endingPage "120389" @default.
- W3171562554 startingPage "120389" @default.
- W3171562554 abstract "The composition of the lower continental crust is estimated via the analysis of granulite xenoliths, granulite terrains and geophysical properties. All three proxies generally agree on the lower crust's refractory nature, dominated by mafic granulites. Estimates weighted using seismic velocity reference models yield lower Th and U concentrations and higher K/U ratios than granulite xenolith averages, while terrain granulites are often much less refractory than xenoliths. Here we present new data for lower crustal xenoliths from central Queensland, an understudied part of the xenolith-bearing eastern Australian basalt provinces. The granulite chemistry was estimated using the reconstitution approach in which the modal mineralogy and in situ chemical analyses are combined. High-resolution energy-dispersive X-ray spectroscopy mapping revealed that K is enriched in anastomosing grain boundary networks and fractures in granulite and co-occurring mantle peridotite xenoliths. Laser-ablation inductively-coupled-plasma mass-spectrometry 2-D traverses show that the same networks are also significantly enriched in many highly incompatible elements. There are sharp concentration contrasts with neighbouring phases for elements with very different diffusivities (Li and U), suggesting that the networks formed during entrainment, decompression and heating within the host basalt. We propose that undetected inclusion of such late enrichment skews xenolith chemistry estimates to non-representative, overly fertile compositions. In the case of the studied xenoliths, the carrier basalts are not very strongly enriched in highly incompatible elements, and even when the K-rich networks are included in the reconstitution, the resulting granulite chemistry is very refractory with 0.52 wt% K 2 O, 0.07 ppm Th and 0.03 ppm U. The locally dominant lithology of lower crustal xenoliths is simple two-pyroxene, plagioclase, ilmenite granulite with few accessory phases. The granulite mineralogy and chemistry were compared with results from thermodynamic models of prograde anatexis of different metabasites, variably hydrated. The comparison shows that the granulites could be restitic calc-alkaline basalts or diorites that experienced episodic melt extraction accumulating up to 50–60% total melt loss at very high temperatures (950–1050 °C), implying that the temperatures recorded by two-pyroxene thermometry (750–830 °C) do not capture the thermal maximum. The corresponding upper crustal section of the northern New England Orogen exposes a range of Devonian to Cretaceous granitoids, some of which have complementary features to the granulites, including the low modal abundance of plagioclase; low relative abundance of Ti, very high Rb/Ba ratios, and high Th/U ratios. Together, the data suggest extensive and protracted melting of the original lower crust upon lithospheric thinning and concomitant magmatic underplating. The required high temperatures favour picritic over basaltic underplates. In such a setting, the gravity-driven delamination of more mafic garnet-rich restites and olivine-rich mafic-ultramafic underplating material is physically plausible. This delamination could help explain the long-established mass balance issue for the formation of continental crust in general." @default.
- W3171562554 created "2021-06-22" @default.
- W3171562554 creator A5075688301 @default.
- W3171562554 creator A5082781738 @default.
- W3171562554 date "2021-10-01" @default.
- W3171562554 modified "2023-10-03" @default.
- W3171562554 title "Evidence for highly refractory, heat producing element-depleted lower continental crust: Some implications for the formation and evolution of the continents" @default.
- W3171562554 cites W1654280627 @default.
- W3171562554 cites W1688191693 @default.
- W3171562554 cites W1965619585 @default.
- W3171562554 cites W1973012528 @default.
- W3171562554 cites W1973766493 @default.
- W3171562554 cites W1975976713 @default.
- W3171562554 cites W1981226676 @default.
- W3171562554 cites W1982286853 @default.
- W3171562554 cites W1991432317 @default.
- W3171562554 cites W1991965761 @default.
- W3171562554 cites W2000325705 @default.
- W3171562554 cites W2003726020 @default.
- W3171562554 cites W2006185623 @default.
- W3171562554 cites W2009541125 @default.
- W3171562554 cites W2021717734 @default.
- W3171562554 cites W2023542164 @default.
- W3171562554 cites W2027025610 @default.
- W3171562554 cites W2030318022 @default.
- W3171562554 cites W2032456215 @default.
- W3171562554 cites W2041398136 @default.
- W3171562554 cites W2042755416 @default.
- W3171562554 cites W2046141409 @default.
- W3171562554 cites W2050574042 @default.
- W3171562554 cites W2050623401 @default.
- W3171562554 cites W2050694750 @default.
- W3171562554 cites W2052958544 @default.
- W3171562554 cites W2056637161 @default.
- W3171562554 cites W2064661989 @default.
- W3171562554 cites W2065065562 @default.
- W3171562554 cites W2067943665 @default.
- W3171562554 cites W2068626653 @default.
- W3171562554 cites W2069317688 @default.
- W3171562554 cites W2070669011 @default.
- W3171562554 cites W2070824287 @default.
- W3171562554 cites W2073179035 @default.
- W3171562554 cites W2075222990 @default.
- W3171562554 cites W2077698686 @default.
- W3171562554 cites W2078475221 @default.
- W3171562554 cites W2082845975 @default.
- W3171562554 cites W2085064498 @default.
- W3171562554 cites W2088076232 @default.
- W3171562554 cites W2089526438 @default.
- W3171562554 cites W2090677492 @default.
- W3171562554 cites W2097207105 @default.
- W3171562554 cites W2100732374 @default.
- W3171562554 cites W2112921184 @default.
- W3171562554 cites W2121912022 @default.
- W3171562554 cites W2123585974 @default.
- W3171562554 cites W2127888210 @default.
- W3171562554 cites W2138522501 @default.
- W3171562554 cites W2143575325 @default.
- W3171562554 cites W2155192741 @default.
- W3171562554 cites W2160930373 @default.
- W3171562554 cites W2165768246 @default.
- W3171562554 cites W2170036199 @default.
- W3171562554 cites W2291506047 @default.
- W3171562554 cites W2325514473 @default.
- W3171562554 cites W2334581221 @default.
- W3171562554 cites W2462542673 @default.
- W3171562554 cites W2472168361 @default.
- W3171562554 cites W2486332874 @default.
- W3171562554 cites W2783626918 @default.
- W3171562554 cites W2789563764 @default.
- W3171562554 cites W2800511095 @default.
- W3171562554 cites W2914231953 @default.
- W3171562554 cites W2942415179 @default.
- W3171562554 cites W2948303101 @default.
- W3171562554 cites W2986143517 @default.
- W3171562554 cites W3037944699 @default.
- W3171562554 cites W3043493819 @default.
- W3171562554 cites W4245770643 @default.
- W3171562554 cites W4246479887 @default.
- W3171562554 doi "https://doi.org/10.1016/j.chemgeo.2021.120389" @default.
- W3171562554 hasPublicationYear "2021" @default.
- W3171562554 type Work @default.
- W3171562554 sameAs 3171562554 @default.
- W3171562554 citedByCount "9" @default.
- W3171562554 countsByYear W31715625542021 @default.
- W3171562554 countsByYear W31715625542022 @default.
- W3171562554 countsByYear W31715625542023 @default.
- W3171562554 crossrefType "journal-article" @default.
- W3171562554 hasAuthorship W3171562554A5075688301 @default.
- W3171562554 hasAuthorship W3171562554A5082781738 @default.
- W3171562554 hasBestOaLocation W31715625542 @default.
- W3171562554 hasConcept C109007969 @default.
- W3171562554 hasConcept C114793014 @default.
- W3171562554 hasConcept C127313418 @default.
- W3171562554 hasConcept C141646446 @default.
- W3171562554 hasConcept C146588470 @default.
- W3171562554 hasConcept C151730666 @default.
- W3171562554 hasConcept C161509811 @default.