Matches in SemOpenAlex for { <https://semopenalex.org/work/W3130972427> ?p ?o ?g. }
- W3130972427 endingPage "106047" @default.
- W3130972427 startingPage "106047" @default.
- W3130972427 abstract "In the Trinity ophiolite, California, USA, several mafic-ultramafic plutons intruded a peridotitic host 435 to 405 m.y. ago in a tectonic setting interpreted as an arc-related spreading centre. One of these intrusions, in the Bear Creek area, exposes basal ultramafic cumulates with igneous layering comprising an alternation of uncommonly thin (down to a few mm) layers of dunite, peridotite and pyroxenite that might be specific to this tectonic setting. These layers offer an excellent opportunity to characterise the microstructure of uncommon cumulates from the lower crust using EBSD (Electron Backscatter Diffraction). This “high-frequency” layering rests on underlying lherzolites and grades upward to more massive pyroxenites (i.e. clinopyroxenites with minor olivine-rich layers). Our field observations and data from the Bear Creek cumulates together with the preservation of magmatic features suggest the environment was tectonically stable after the emplacement of the cumulates. A detailed microstructural investigation of all minerals from the Bear Creek cumulates allows us to decipher their magmatic and plastic deformation history. In a structural reference frame defined by the compositional layering and the elongation direction of the surrounding host peridotites, olivine in the cumulates presents a [010]-fibre fabric and rarely a [001](010) fabric. Clinopyroxene shows a concentration of [010] axes normal to the layering plane with [100] and [001] defining girdles. Orthopyroxene mostly has a fabric with [100] and/or [010] subnormal to the layering plane and [001] scattered along a girdle in the plane of layering. All minerals show a strong fabric. We interpret the formation of the developed planar microstructures as a result of magmatic processes, with high contribution of crystal settling. To a lesser extent, compaction could have been operating and may be linked to the rare evidence of plastic deformation. Clusters of axes within the girdles of olivine and pyroxene CPOs preferentially appear close to the direction of elongation of the surrounding peridotites (i.e. N115°). EBSD analysis of the shape-preferred orientation of Bear Creek's minerals revealed a preferential alignment of the olivine and cpx long axis with the N°115 direction. This magmatic lineation and the preferred direction in the CPOs girdles are both consistent with the stretching lineation acquired during solid-state deformation by the mantle peridotite of the Trinity ophiolite. We suggest that a weak magma flux early on and/or an ongoing but limited regional stress could be responsible for these clusters. Although a direct coupling between asthenospheric flow and magmatic flow cannot be invoked in this context of melt intrusion in the lithosphere, this result highlights that the stress field applied on the mantle could have been still active and similar during the formation of Bear Creek intrusion. Our new field and microstructural data, together with previously presented petrological data, fit a scenario for the evolution of the Trinity ophiolite in which a mantle segment was intruded by a single large batch of primitive boninitic-andesitic melt. Our results emphasise the importance of considering the initial magmatic microstructures and the original shape anisotropy when investigating later deformation in ultramafic rocks." @default.
- W3130972427 created "2021-03-01" @default.
- W3130972427 creator A5018490251 @default.
- W3130972427 creator A5021690261 @default.
- W3130972427 creator A5040292900 @default.
- W3130972427 creator A5055379878 @default.
- W3130972427 creator A5059702083 @default.
- W3130972427 creator A5060345705 @default.
- W3130972427 creator A5084184943 @default.
- W3130972427 creator A5091296844 @default.
- W3130972427 date "2021-05-01" @default.
- W3130972427 modified "2023-10-14" @default.
- W3130972427 title "The microstructure of layered ultramafic cumulates: Case study of the Bear Creek intrusion, Trinity ophiolite, California, USA" @default.
- W3130972427 cites W1599507010 @default.
- W3130972427 cites W1964060042 @default.
- W3130972427 cites W1968512915 @default.
- W3130972427 cites W1972933621 @default.
- W3130972427 cites W1973274380 @default.
- W3130972427 cites W1973990596 @default.
- W3130972427 cites W1975206388 @default.
- W3130972427 cites W1983341808 @default.
- W3130972427 cites W1993787378 @default.
- W3130972427 cites W1995448308 @default.
- W3130972427 cites W1997911623 @default.
- W3130972427 cites W2000246012 @default.
- W3130972427 cites W2005488558 @default.
- W3130972427 cites W2013544146 @default.
- W3130972427 cites W2014783682 @default.
- W3130972427 cites W2015008469 @default.
- W3130972427 cites W2020047493 @default.
- W3130972427 cites W2025388825 @default.
- W3130972427 cites W2025835487 @default.
- W3130972427 cites W2029548885 @default.
- W3130972427 cites W2036293114 @default.
- W3130972427 cites W2038669248 @default.
- W3130972427 cites W2041297839 @default.
- W3130972427 cites W2044461110 @default.
- W3130972427 cites W2045037966 @default.
- W3130972427 cites W2054444124 @default.
- W3130972427 cites W2055988738 @default.
- W3130972427 cites W2058102242 @default.
- W3130972427 cites W2061693741 @default.
- W3130972427 cites W2062018184 @default.
- W3130972427 cites W2067180655 @default.
- W3130972427 cites W2071999365 @default.
- W3130972427 cites W2079140883 @default.
- W3130972427 cites W2104780445 @default.
- W3130972427 cites W2109396998 @default.
- W3130972427 cites W2119873397 @default.
- W3130972427 cites W2122439573 @default.
- W3130972427 cites W2139033417 @default.
- W3130972427 cites W2142289674 @default.
- W3130972427 cites W2153077083 @default.
- W3130972427 cites W2164054055 @default.
- W3130972427 cites W2164451697 @default.
- W3130972427 cites W2164507998 @default.
- W3130972427 cites W2314209761 @default.
- W3130972427 cites W2320631089 @default.
- W3130972427 cites W2328265254 @default.
- W3130972427 cites W2407060582 @default.
- W3130972427 cites W2519480605 @default.
- W3130972427 cites W2624652019 @default.
- W3130972427 cites W2727103234 @default.
- W3130972427 cites W2736726744 @default.
- W3130972427 cites W2782370156 @default.
- W3130972427 cites W2802439723 @default.
- W3130972427 cites W2885039012 @default.
- W3130972427 cites W2928694646 @default.
- W3130972427 cites W4255546529 @default.
- W3130972427 doi "https://doi.org/10.1016/j.lithos.2021.106047" @default.
- W3130972427 hasPublicationYear "2021" @default.
- W3130972427 type Work @default.
- W3130972427 sameAs 3130972427 @default.
- W3130972427 citedByCount "1" @default.
- W3130972427 countsByYear W31309724272023 @default.
- W3130972427 crossrefType "journal-article" @default.
- W3130972427 hasAuthorship W3130972427A5018490251 @default.
- W3130972427 hasAuthorship W3130972427A5021690261 @default.
- W3130972427 hasAuthorship W3130972427A5040292900 @default.
- W3130972427 hasAuthorship W3130972427A5055379878 @default.
- W3130972427 hasAuthorship W3130972427A5059702083 @default.
- W3130972427 hasAuthorship W3130972427A5060345705 @default.
- W3130972427 hasAuthorship W3130972427A5084184943 @default.
- W3130972427 hasAuthorship W3130972427A5091296844 @default.
- W3130972427 hasBestOaLocation W31309724272 @default.
- W3130972427 hasConcept C127313418 @default.
- W3130972427 hasConcept C139347428 @default.
- W3130972427 hasConcept C151730666 @default.
- W3130972427 hasConcept C167284885 @default.
- W3130972427 hasConcept C17409809 @default.
- W3130972427 hasConcept C176055353 @default.
- W3130972427 hasConcept C195081551 @default.
- W3130972427 hasConcept C23923706 @default.
- W3130972427 hasConcept C2776698055 @default.
- W3130972427 hasConcept C2780364934 @default.
- W3130972427 hasConcept C34122518 @default.
- W3130972427 hasConcept C59822182 @default.
- W3130972427 hasConcept C67236022 @default.