Matches in SemOpenAlex for { <https://semopenalex.org/work/W2188332474> ?p ?o ?g. }
Showing items 1 to 69 of
69
with 100 items per page.
- W2188332474 abstract "A felsic volcanic series (605-825 mbsf) overlain by upper Eocene shallow-water sediments (500-605 mbsf) and basalticandesitic sills that intruded into sediments of Holocene to Miocene age (0-500 mbsf) was drilled in the forearc region of the Lau Basin at a water depth of 4810 m. The volcanic sequence at Site 841 includes altered and mineralized calc-alkaline rhyolites and dacites, dacitic tuffs, lapilli tuffs, flow breccias, and welded tuffs. These rocks formed subaerially or in a very shallow-water environment suffering a subsidence of >5000 m since Eocene times. Calculations of gains and losses of the major components during alteration show most pronounced changes in the uppermost 70 m of the volcanic sequence. Here, Al, Fe, Mg, and K are enriched, whereas Si and Na are strongly depleted. Hike, vermiculite, chlorite, and hematite predominate in this part of the hole. Throughout the section, quartz, Plagioclase, kaolinite, and calcite are present. Sulfide mineralization (up to 10 vol%) consisting mainly of disseminated pyrite (with minor pyrrhotite inclusions) and marcasite together with minor amounts of chalcopyrite is pervasive throughout. Locally, a few sulfide-bearing quartz-carbonate veins as well as Ti-amphibole replacement by rutile and then by pyrite were observed. Strong variations in the As content of sulfides (from 0 to 0.69 wt%) from the same depth interval and local enrichments of Co, Ni, and Cu in pyrite are interpreted to result from fluctuations in fluid composition. Calculations of oxygen and sulfur fugacities indicate that fθ 2 and fS2 were high at the top and lower at the bottom of the sequence. Sulfur isotope determinations on separated pyrite grains from two samples give δ34S values of+6.4‰ and +8.4‰, which are close to those reported from Kuroko and Okinawa Trough massive sulfide deposits and calc-alkaline volcanic rocks of the Japanese Ryukyu Island Arc. Calculated chlorite formation temperatures of 265°-290°C at the top of the sequence are consistent with minimum formation temperatures of fluid inclusions in secondary quartz, revealing a narrow range of 270°-297°C. Chlorite formation temperatures are constant downhole and do not exceed 300°C. The presence of marcasite and 4C-type pyrrhotite indicates a formation temperature of <250°C. At a later stage, illite was formed at the top of the volcanic series at temperatures well below 200°C." @default.
- W2188332474 created "2016-06-24" @default.
- W2188332474 creator A5006174119 @default.
- W2188332474 creator A5034533692 @default.
- W2188332474 date "1994-05-01" @default.
- W2188332474 modified "2023-09-23" @default.
- W2188332474 title "Hydrothermally Altered Felsic Rocks of the Tonga Forearc" @default.
- W2188332474 cites W1987939856 @default.
- W2188332474 cites W1999448338 @default.
- W2188332474 cites W2018932687 @default.
- W2188332474 cites W2021186019 @default.
- W2188332474 cites W2022747145 @default.
- W2188332474 cites W2032405550 @default.
- W2188332474 cites W2036342458 @default.
- W2188332474 cites W2049956359 @default.
- W2188332474 cites W2054578927 @default.
- W2188332474 cites W2054643770 @default.
- W2188332474 cites W2064506966 @default.
- W2188332474 cites W2069905115 @default.
- W2188332474 cites W2076626505 @default.
- W2188332474 cites W2076981416 @default.
- W2188332474 cites W2082645751 @default.
- W2188332474 cites W2099535239 @default.
- W2188332474 cites W2138822821 @default.
- W2188332474 cites W2166873451 @default.
- W2188332474 doi "https://doi.org/10.2973/odp.proc.sr.135.130.1994" @default.
- W2188332474 hasPublicationYear "1994" @default.
- W2188332474 type Work @default.
- W2188332474 sameAs 2188332474 @default.
- W2188332474 citedByCount "2" @default.
- W2188332474 crossrefType "book-chapter" @default.
- W2188332474 hasAuthorship W2188332474A5006174119 @default.
- W2188332474 hasAuthorship W2188332474A5034533692 @default.
- W2188332474 hasBestOaLocation W21883324741 @default.
- W2188332474 hasConcept C120806208 @default.
- W2188332474 hasConcept C127313418 @default.
- W2188332474 hasConcept C165205528 @default.
- W2188332474 hasConcept C17409809 @default.
- W2188332474 hasConcept C193429443 @default.
- W2188332474 hasConcept C58097730 @default.
- W2188332474 hasConcept C5900021 @default.
- W2188332474 hasConcept C77928131 @default.
- W2188332474 hasConcept C94436079 @default.
- W2188332474 hasConceptScore W2188332474C120806208 @default.
- W2188332474 hasConceptScore W2188332474C127313418 @default.
- W2188332474 hasConceptScore W2188332474C165205528 @default.
- W2188332474 hasConceptScore W2188332474C17409809 @default.
- W2188332474 hasConceptScore W2188332474C193429443 @default.
- W2188332474 hasConceptScore W2188332474C58097730 @default.
- W2188332474 hasConceptScore W2188332474C5900021 @default.
- W2188332474 hasConceptScore W2188332474C77928131 @default.
- W2188332474 hasConceptScore W2188332474C94436079 @default.
- W2188332474 hasLocation W21883324741 @default.
- W2188332474 hasOpenAccess W2188332474 @default.
- W2188332474 hasPrimaryLocation W21883324741 @default.
- W2188332474 hasRelatedWork W2004378897 @default.
- W2188332474 hasRelatedWork W2015749641 @default.
- W2188332474 hasRelatedWork W2067421025 @default.
- W2188332474 hasRelatedWork W2092286779 @default.
- W2188332474 hasRelatedWork W2349947565 @default.
- W2188332474 hasRelatedWork W2375244954 @default.
- W2188332474 hasRelatedWork W2735800479 @default.
- W2188332474 hasRelatedWork W2977802646 @default.
- W2188332474 hasRelatedWork W3172099227 @default.
- W2188332474 hasRelatedWork W2776088913 @default.
- W2188332474 isParatext "false" @default.
- W2188332474 isRetracted "false" @default.
- W2188332474 magId "2188332474" @default.
- W2188332474 workType "book-chapter" @default.