Matches in SemOpenAlex for { <https://semopenalex.org/work/W1975660531> ?p ?o ?g. }
- W1975660531 endingPage "473" @default.
- W1975660531 startingPage "459" @default.
- W1975660531 abstract "A high-temperature contact is described between the basal pargasite-bearing spinel-lherzolites of the Bay of Islands ophiolite complex and underlying garnet-granulite facies metagabbros of its dynamothermal aureole. Three distinct high-temperature hydrous assemblages occur in the basal mylonites of the peridotite, and spinel- and garnet-bearing corona textures indicative of increase in pressure under constant or increasing temperature conditions are described for the first time from the uppermost part of the aureole. On the basis of garnet-clinopyroxene geothermometry and garnet-forming reactions in metabasic rocks, P−T conditions of 7–11 kbar, 750–850°C are estimated for rocks on both sides of the contact. Steep inverted gradients in both temperature and pressure of equilibration occur in the aureole, which most likely represents a thinned, overturned and metamorphosed section through an ophiolite sequence. It is proposed that the aureole formed in a low-angle shear zone cutting the oceanic crust and upper mantle. Age data shows that the Bay of Islands Complex was 30–40 Ma old and therefore relatively cold at the time of formation of the aureole. Prolonged (> 1 Ma) shear heating must therefore have occurred at high shear stresses and movement rates (≥ 1 kbar, 10 cm/yr) to produce the high contact temperatures. The displacement surface probably initiated as a discrete fault, evolving into a viscous shear zone with time. Downward movement of the locus of shearing into weaker lithologies and finally thrusting of the ophiolite-aureole complex over cold sediments accounts for the preservation of steep metamorphic gradients in the aureole. The observed pressures at the ophiolite-aureole contact are 3–7 kbar in excess of the expected load pressure from the present thickness of the ophiolite. The cause of the pressure excess was removed before formation of lower-grade parts of the aureole. Possible explanations are tectonic thinning of the ophiolite during displacement or more likely emplacement of nappes on top of the ophiolite before formation of the aureole. A model involving detachment of the ophiolite slice from below a subduction zone can account for the high pressures, rapid uplift and erosion during displacement, and the coincidence of K-Ar ages of amphiboles from the aureole and the sheeted dyke complex of the ophiolite." @default.
- W1975660531 created "2016-06-24" @default.
- W1975660531 creator A5017639088 @default.
- W1975660531 date "1983-06-01" @default.
- W1975660531 modified "2023-09-25" @default.
- W1975660531 title "P−T conditions during emplacement of the Bay of Islands ophiolite complex" @default.
- W1975660531 cites W1975368712 @default.
- W1975660531 cites W1980253322 @default.
- W1975660531 cites W1996038144 @default.
- W1975660531 cites W1996887763 @default.
- W1975660531 cites W2003641336 @default.
- W1975660531 cites W2004783515 @default.
- W1975660531 cites W2006450096 @default.
- W1975660531 cites W2013105174 @default.
- W1975660531 cites W2020258206 @default.
- W1975660531 cites W2023858897 @default.
- W1975660531 cites W2025761960 @default.
- W1975660531 cites W2026125888 @default.
- W1975660531 cites W2031211027 @default.
- W1975660531 cites W2035042691 @default.
- W1975660531 cites W2038177379 @default.
- W1975660531 cites W2041840839 @default.
- W1975660531 cites W2042226801 @default.
- W1975660531 cites W2043676912 @default.
- W1975660531 cites W2048912820 @default.
- W1975660531 cites W2049603471 @default.
- W1975660531 cites W2059013108 @default.
- W1975660531 cites W2073955593 @default.
- W1975660531 cites W2077609916 @default.
- W1975660531 cites W2086413117 @default.
- W1975660531 cites W2088253398 @default.
- W1975660531 cites W2091579300 @default.
- W1975660531 cites W2095982458 @default.
- W1975660531 cites W2100045638 @default.
- W1975660531 cites W2101934152 @default.
- W1975660531 cites W2120418460 @default.
- W1975660531 cites W2126037538 @default.
- W1975660531 cites W2132849481 @default.
- W1975660531 cites W2134214654 @default.
- W1975660531 cites W2138167172 @default.
- W1975660531 cites W2139787852 @default.
- W1975660531 cites W2145604970 @default.
- W1975660531 cites W2155128667 @default.
- W1975660531 cites W2157583759 @default.
- W1975660531 cites W2163330623 @default.
- W1975660531 cites W2316342165 @default.
- W1975660531 cites W2319661330 @default.
- W1975660531 cites W4241779873 @default.
- W1975660531 doi "https://doi.org/10.1016/0012-821x(83)90118-8" @default.
- W1975660531 hasPublicationYear "1983" @default.
- W1975660531 type Work @default.
- W1975660531 sameAs 1975660531 @default.
- W1975660531 citedByCount "32" @default.
- W1975660531 countsByYear W19756605312013 @default.
- W1975660531 countsByYear W19756605312014 @default.
- W1975660531 countsByYear W19756605312016 @default.
- W1975660531 countsByYear W19756605312018 @default.
- W1975660531 countsByYear W19756605312020 @default.
- W1975660531 countsByYear W19756605312023 @default.
- W1975660531 crossrefType "journal-article" @default.
- W1975660531 hasAuthorship W1975660531A5017639088 @default.
- W1975660531 hasConcept C109007969 @default.
- W1975660531 hasConcept C114793014 @default.
- W1975660531 hasConcept C127313418 @default.
- W1975660531 hasConcept C146588470 @default.
- W1975660531 hasConcept C154200439 @default.
- W1975660531 hasConcept C165205528 @default.
- W1975660531 hasConcept C17409809 @default.
- W1975660531 hasConcept C18142444 @default.
- W1975660531 hasConcept C197737763 @default.
- W1975660531 hasConcept C23295444 @default.
- W1975660531 hasConcept C23923706 @default.
- W1975660531 hasConcept C26687426 @default.
- W1975660531 hasConcept C2780364934 @default.
- W1975660531 hasConcept C58097730 @default.
- W1975660531 hasConcept C5900021 @default.
- W1975660531 hasConcept C67236022 @default.
- W1975660531 hasConcept C77928131 @default.
- W1975660531 hasConcept C84372278 @default.
- W1975660531 hasConcept C96035792 @default.
- W1975660531 hasConceptScore W1975660531C109007969 @default.
- W1975660531 hasConceptScore W1975660531C114793014 @default.
- W1975660531 hasConceptScore W1975660531C127313418 @default.
- W1975660531 hasConceptScore W1975660531C146588470 @default.
- W1975660531 hasConceptScore W1975660531C154200439 @default.
- W1975660531 hasConceptScore W1975660531C165205528 @default.
- W1975660531 hasConceptScore W1975660531C17409809 @default.
- W1975660531 hasConceptScore W1975660531C18142444 @default.
- W1975660531 hasConceptScore W1975660531C197737763 @default.
- W1975660531 hasConceptScore W1975660531C23295444 @default.
- W1975660531 hasConceptScore W1975660531C23923706 @default.
- W1975660531 hasConceptScore W1975660531C26687426 @default.
- W1975660531 hasConceptScore W1975660531C2780364934 @default.
- W1975660531 hasConceptScore W1975660531C58097730 @default.
- W1975660531 hasConceptScore W1975660531C5900021 @default.
- W1975660531 hasConceptScore W1975660531C67236022 @default.
- W1975660531 hasConceptScore W1975660531C77928131 @default.
- W1975660531 hasConceptScore W1975660531C84372278 @default.