Matches in SemOpenAlex for { <https://semopenalex.org/work/W2004161620> ?p ?o ?g. }
- W2004161620 endingPage "2746" @default.
- W2004161620 startingPage "2735" @default.
- W2004161620 abstract "The Enstatite-Oldhamite Geothermometer (EOG) developed by Larimer and Buseck (1974) makes use of the five-phase assemblage kamacite, quartz, enstatite, oldhamite, troilite to determine metamorphic temperatures in enstatite chondrites. A re-evaluation of the thermodynamic foundation of the EOG shows that several of the assumptions and approximations can be significantly improved with new thermodynamic data. The geothermometer has been modified to reflect, among other things, the solution behavior of Si in kamacite, the solution behavior of a calcium silicate component in enstatite, and metal sulfide fusion as a function of temperature and composition. An analysis of the EOG shows that the activity coefficient of Si in kamacite and the Ca-rich component of enstatite are the model's most important parameters. For Si, the activity coefficient data of Sakao and Elliot (1975) have been used. The activity coefficient of a Ca-rich component of enstatite presents a unique problem since data on this parameter do not exist for one-pyroxene systems and two-pyroxene solution models do not provide unique activity coefficients in the absence of diopside. The model, therefore, has been formulated using CaMgSi2O6 as the Ca-rich component of enstatite and assumes that it behaves as a symmetric regular Margules solution. The Margules interaction parameter WG is then used as an adjustable constant and is varied such that the resulting temperatures fall between minimum and maximum temperatures determined independently. Temperature minima were determined from the enstatite-diopside solvus of Carlson (1986) and indicate that the EL6 chondrites have been metamorphosed to temperatures exceeding 900–1000°C. The temperature of the enstatite-plagioclase-quartz eutectic (1090°C), appropriate for EL6 plagioclase compositions, was used as the metamorphic maxima. With these constraints, a WG value of 52 kJ/mole was estimated as appropriate (within the context of the model) for EL6 metamorphic conditions. EL6 temperatures determined via this method range from 981°C for Yilmia to 1068°C for Blithfield. Temperature estimates of greater than 1000°C for the highly equilibrated EL6 chondrites require the formation of a metal-sulfide liquid during metamorphism. Liquid fractionation of this predominantly Fe-FeS liquid could explain the siderophile, chalcophile, and volatile element depletion in the EL6 class relative to CI and EH chondrites. Liquid fractionation, however, is not required by the model and is consistent with a moderate cooling rate, which is fast enough to lock in high CaO contents in enstatite but slow enough to re-equilibrate troilite and alabandite to low temperatures. The oxygen fugacity determined in this study shows the enstatite chondrites to have equilibrated at extremely low fO2. This, as well as the activity of Si that can be extracted from the EOG, indicates that the enstatite chondrites that contain sinoite (Si2N2O) equilibrated under high nitrogen fugacities. High fN2 values imply that sinoite-bearing E-chondrites either formed in a nebula of high pressure (fN2 = 10−1 at 1050°C) or, more likely, are products of planetary metamorphism." @default.
- W2004161620 created "2016-06-24" @default.
- W2004161620 creator A5050652601 @default.
- W2004161620 creator A5053494946 @default.
- W2004161620 creator A5067169746 @default.
- W2004161620 date "1989-10-01" @default.
- W2004161620 modified "2023-09-26" @default.
- W2004161620 title "Intensive parameters of enstatite chondrite metamorphism" @default.
- W2004161620 cites W1603509724 @default.
- W2004161620 cites W1973189105 @default.
- W2004161620 cites W1989814565 @default.
- W2004161620 cites W2003151337 @default.
- W2004161620 cites W2005907971 @default.
- W2004161620 cites W2015172402 @default.
- W2004161620 cites W2019655894 @default.
- W2004161620 cites W2020846560 @default.
- W2004161620 cites W2022097003 @default.
- W2004161620 cites W2024408494 @default.
- W2004161620 cites W2027172946 @default.
- W2004161620 cites W2033167553 @default.
- W2004161620 cites W2044109160 @default.
- W2004161620 cites W2048483458 @default.
- W2004161620 cites W2050088173 @default.
- W2004161620 cites W2055985810 @default.
- W2004161620 cites W2063888517 @default.
- W2004161620 cites W2069173644 @default.
- W2004161620 cites W2083305310 @default.
- W2004161620 cites W2087353678 @default.
- W2004161620 cites W2088868821 @default.
- W2004161620 cites W2110147591 @default.
- W2004161620 cites W2122952645 @default.
- W2004161620 cites W2329638536 @default.
- W2004161620 cites W2917745643 @default.
- W2004161620 cites W4236427650 @default.
- W2004161620 cites W52063898 @default.
- W2004161620 doi "https://doi.org/10.1016/0016-7037(89)90145-2" @default.
- W2004161620 hasPublicationYear "1989" @default.
- W2004161620 type Work @default.
- W2004161620 sameAs 2004161620 @default.
- W2004161620 citedByCount "49" @default.
- W2004161620 countsByYear W20041616202012 @default.
- W2004161620 countsByYear W20041616202013 @default.
- W2004161620 countsByYear W20041616202014 @default.
- W2004161620 countsByYear W20041616202015 @default.
- W2004161620 countsByYear W20041616202016 @default.
- W2004161620 countsByYear W20041616202017 @default.
- W2004161620 countsByYear W20041616202019 @default.
- W2004161620 countsByYear W20041616202020 @default.
- W2004161620 countsByYear W20041616202021 @default.
- W2004161620 countsByYear W20041616202022 @default.
- W2004161620 crossrefType "journal-article" @default.
- W2004161620 hasAuthorship W2004161620A5050652601 @default.
- W2004161620 hasAuthorship W2004161620A5053494946 @default.
- W2004161620 hasAuthorship W2004161620A5067169746 @default.
- W2004161620 hasConcept C116862484 @default.
- W2004161620 hasConcept C121332964 @default.
- W2004161620 hasConcept C127313418 @default.
- W2004161620 hasConcept C1276947 @default.
- W2004161620 hasConcept C130635790 @default.
- W2004161620 hasConcept C151730666 @default.
- W2004161620 hasConcept C199289684 @default.
- W2004161620 hasConcept C2776283581 @default.
- W2004161620 hasConcept C2776342828 @default.
- W2004161620 hasConcept C2776693292 @default.
- W2004161620 hasConcept C2777018398 @default.
- W2004161620 hasConcept C2777156721 @default.
- W2004161620 hasConcept C2778998827 @default.
- W2004161620 hasConcept C2779181077 @default.
- W2004161620 hasConcept C2779208318 @default.
- W2004161620 hasConcept C2779870107 @default.
- W2004161620 hasConcept C2780364934 @default.
- W2004161620 hasConcept C76349523 @default.
- W2004161620 hasConcept C97355855 @default.
- W2004161620 hasConceptScore W2004161620C116862484 @default.
- W2004161620 hasConceptScore W2004161620C121332964 @default.
- W2004161620 hasConceptScore W2004161620C127313418 @default.
- W2004161620 hasConceptScore W2004161620C1276947 @default.
- W2004161620 hasConceptScore W2004161620C130635790 @default.
- W2004161620 hasConceptScore W2004161620C151730666 @default.
- W2004161620 hasConceptScore W2004161620C199289684 @default.
- W2004161620 hasConceptScore W2004161620C2776283581 @default.
- W2004161620 hasConceptScore W2004161620C2776342828 @default.
- W2004161620 hasConceptScore W2004161620C2776693292 @default.
- W2004161620 hasConceptScore W2004161620C2777018398 @default.
- W2004161620 hasConceptScore W2004161620C2777156721 @default.
- W2004161620 hasConceptScore W2004161620C2778998827 @default.
- W2004161620 hasConceptScore W2004161620C2779181077 @default.
- W2004161620 hasConceptScore W2004161620C2779208318 @default.
- W2004161620 hasConceptScore W2004161620C2779870107 @default.
- W2004161620 hasConceptScore W2004161620C2780364934 @default.
- W2004161620 hasConceptScore W2004161620C76349523 @default.
- W2004161620 hasConceptScore W2004161620C97355855 @default.
- W2004161620 hasIssue "10" @default.
- W2004161620 hasLocation W20041616201 @default.
- W2004161620 hasOpenAccess W2004161620 @default.
- W2004161620 hasPrimaryLocation W20041616201 @default.
- W2004161620 hasRelatedWork W1603730490 @default.
- W2004161620 hasRelatedWork W1656039501 @default.