Process of crustal formation of the Rayner Complex, Enderby Land, East Antarctica

东南极洲恩德比地雷纳复合体的地壳形成过程

• 批准号: 08640584
• 负责人: SHIRAISHI Kazuyuki
• 金额: $ 1.09万
• 依托单位: National Institute of Polar Research
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640584/
• 关键词: East Antarctica; Geochronology; TTG; Napier Complex; SHRIMP; Gondwana; Ultra-high temperature metamorphism; continental crust; レイナ-岩体; セルロンダーネ; 変成作用; イオンマイクロプローブ

The correspondence between metamorphic P-T path and geochronology is the most important issue on the discussion of the formation and evolution of continents. Enderby Land in East Antarctica is the one of the suitable areas for this study. This study aims re-examination of the geological framework in the Enderby Land and it's vicinity. The results would constrain the formation of the supercontinets in Precambrian, particularly it is expected to reveal the Grenvilian event, the world-wide orogeny in the middle to late Proterozoic. Following results have been obtained so far ; 1) The Rayner Complex and the Lutzow-Holm Complex (LHC) show similar metamorphic history of the clockwise retrograde P-T paths. 2) Tonalitic rocks in the Sor Rondane Mountains and metatrondjhemite in LHC have similar geochronological and geochemical characteristics. The petrogenesis for these p.lutonic rocks is interpreted by the melting of hot slabs which were transformed into garnet amphibolite. 3) Detailed petrographic study on the sapphirine-and osumilite-bearing paragenesis in the Napier Complex revealed that the physical condition of ultra-high temperature metamorphism reached more than 1000C and 7-8 kbar. Moreover, two-stage P-T paths were found, suggesting the intrusion of hot pluton into the middle crust as the heat source.

变质质P-T路径与年代学的对应关系是讨论大陆形成演化中最重要的问题。南极洲东部的恩德比地是这项研究的合适地区之一。本研究旨在重新检查恩德比地及其周边地区的地质框架。这些结果将限制前寒武纪超级大陆的形成，特别是有望揭示格伦维尔事件，即中元古代中晚期的世界性造山运动。目前已取得以下成果； 1) Rayner 复合体和 Lutzow-Holm 复合体 (LHC) 显示出类似的顺时针逆行 P-T 路径的变质历史。 2）Sor Rondane山脉的英英闪长岩和大型强子对撞机中的变辉长铁矿具有相似的地质年代学和地球化学特征。这些成岩成因是通过热板片的熔化转化为石榴石角闪岩来解释的。 3）对Napier杂岩中含蓝宝石和锇石共生的详细岩相研究表明，超高温变质作用的物理条件达到1000C以上和7-8 kbar。此外，还发现了两阶段的P-T路径，表明热岩体侵入中地壳作为热源。

项目成果

Ikeda.Y.: "Petrogenesis of the meta-trondhjemites from Cape Hinode,East Antactica." Proc.NIPR Symp.Antarct Geosci.10. 102-110 (1997)

Ikeda.Y.：“来自东安塔利卡日出岬的meta-trondhjemites的岩石成因。”

Hiroi, Y., Motoyoshf, Y., Ellis, D.J., Shiraishi, K.and Kondo, Y.: "The significance of phosphorous zonation in garnet from high grade pelitic rocks : a new indicator of partial melting." The Antarctic Region. 73-77 (1997)

Hiroi, Y.、Motoyoshf, Y.、Ellis, D.J.、Shiraishi, K. 和 Kondo, Y.：“高品位泥质岩石榴石中磷分带的意义：部分熔融的新指标。”

白石和行: "南極から見たゴンドワナ" 月刊地球. 18. 404-409 (1996)

白石和之：“从南极洲看到的冈瓦纳大陆”月刊地球。 18. 404-409 (1996)

Shaw, R.: "Proterozoic events in the Eastern Ghats granulite belt,India:Evidence from Rb-Sr,Sm-Nd systematics,and SHRIMP dating." Jour.Geology. 105. 645-656 (1997)

Shaw, R.：“印度东高止麻粒岩带的元古代事件：来自 Rb-Sr、Sm-Nd 系统学和 SHRIMP 测年的证据。”

Shiraishi, K.: "Re-examination of the metamorphic and protolith ages of the Rayner complex.Antarctica:Evidence for the Cambrian(Pan-African)" The Antarctic Region. 79-88 (1997)

Shiraishi, K.：“重新审视雷纳杂岩的变质和原岩年龄。南极洲：寒武纪（泛非）的证据”南极地区。