Scholarlink

<p>The petrography, mineral chemistry, geochemistry, and geochronology of 5 kimberlite bodies from the Victoria Island kimberlite field, Nunavut/Northwest Territories, Canada, are presented. Samples from dyke and pipe complexes from the King Eider and the Galaxy clusters were analyzed. Their geochemical (major and trace element, plus Sr-Nd-Hf systematics) and mineralogical (dominantly zoned phlogopite-eastonite mica and Trend 1 spinel) signatures are consistent with archetypal kimberlites. The majority of the samples reveal variable but typically limited crustal contamination, mainly of limestone xenoliths that are visible in drill core and hand specimen. Mildly depleted εNd<sub>i</sub> (+ 1.4 to + 2.6) and εHf<sub>i</sub> (+ 4.7 to + 8.4) isotopic signatures indicate an asthenospheric source and conform well to the Pre-Mesozoic temporal trend for global kimberlite sources. Variation in εSr<sub>i</sub> (+ 4.7 to + 19.9) indicates the effect of contamination by local carbonate supracrustal rocks. Rb-Sr mica and U-Pb perovskite geochronology extends the age range for the Victoria Island kimberlites (286 to 241&#xa0;Ma) into the Middle Triassic, yielding a ~ 45 Myr period of active kimberlite magmatism within the field. The Darnley Bay kimberlite, Parry Peninsula, 600&#xa0;km southwest of the Victoria Island kimberlite field yields a Permian age 275&#xa0;Ma, overlapping the ages of the Victoria Island field. We consider a number of potential triggers for both kimberlite fields, concluding that the early phase of the ascending Great Meteor mantle plume, that has been linked to kimberlite magmatism further southeast at Rankin Inlet during the Late Triassic, may have been responsible.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Geochronology, mineral chemistry, and geochemistry of kimberlites from Victoria Island, Arctic Canada

  • 期刊论文

  • 发表日期：

    2025年6月14日

查看全文
  • Alex A. Müller,
  • Chiranjeeb Sarkar,
  • Bruce A. Kjarsgaard,
  • James LeBlanc,
  • Soumendu Sarkar,
  • Sarah J. Woodland,
  • D. Graham Pearson

摘要

The petrography, mineral chemistry, geochemistry, and geochronology of 5 kimberlite bodies from the Victoria Island kimberlite field, Nunavut/Northwest Territories, Canada, are presented. Samples from dyke and pipe complexes from the King Eider and the Galaxy clusters were analyzed. Their geochemical (major and trace element, plus Sr-Nd-Hf systematics) and mineralogical (dominantly zoned phlogopite-eastonite mica and Trend 1 spinel) signatures are consistent with archetypal kimberlites. The majority of the samples reveal variable but typically limited crustal contamination, mainly of limestone xenoliths that are visible in drill core and hand specimen. Mildly depleted εNdi (+ 1.4 to + 2.6) and εHfi (+ 4.7 to + 8.4) isotopic signatures indicate an asthenospheric source and conform well to the Pre-Mesozoic temporal trend for global kimberlite sources. Variation in εSri (+ 4.7 to + 19.9) indicates the effect of contamination by local carbonate supracrustal rocks. Rb-Sr mica and U-Pb perovskite geochronology extends the age range for the Victoria Island kimberlites (286 to 241 Ma) into the Middle Triassic, yielding a ~ 45 Myr period of active kimberlite magmatism within the field. The Darnley Bay kimberlite, Parry Peninsula, 600 km southwest of the Victoria Island kimberlite field yields a Permian age 275 Ma, overlapping the ages of the Victoria Island field. We consider a number of potential triggers for both kimberlite fields, concluding that the early phase of the ascending Great Meteor mantle plume, that has been linked to kimberlite magmatism further southeast at Rankin Inlet during the Late Triassic, may have been responsible.