Pan-African event in the East Antarctica : significance in the formation of the Gondwana

东南极洲泛非事件：对冈瓦纳大陆形成的意义

基本信息

批准号：
06640591
负责人：
SHIRAISHI Kazuyuki
金额：
$ 1.15万
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 General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640591/
关键词：
East Antarctica Geochronology Metamorphism Ion Microprobe SHRIMP Gondwana Pan-African Proterozoic

项目摘要

1. The metamorphic and protolith ages of the Rayner Complex(RC) have been examined using SHRIMP U-Pb zircon ages in combination with Sm-Nd and Rb-Sr mineral and whole rock isochron ages. Within the RC we have determined distinct Proterozoic to Cambrian events ; -520-540 Ma at the coastal outcrops, -900-1000 Ma in more inland outcrops. These ages are considered to represent two high-grade metamorphic events. Another grouping of U-Pb zircon ages at -780-800 Ma is consistent with previously reported 770 Ma igneous activity. we intend to further examine the extent and nature of this event. The new U-Pb zircon data show that part of the area formerly considered to represent the western margin of the Proterozoic Rayner Complex underwent high grade metamorphism during the Cambrian (Pan-African) and we propose that it is an eastward continuation of the Lutzow-Holm Complex (LHC).2. A Rb-Sr and Sm-Nd isotope study of meta-trondhjemites and a pelitic gneiss from Cape Hinode, LHC,has been performe … More d. Taking into account the initial ratios and the previous zircon U-Pb study, we concluded that the -1000 Ma age indicates the time of igneous crystallization of the trondhjemite. The pelitic gneiss, which probably originated from middle Proterozoic supracrustal material, is the host rock of the trondhjemite intrusion. However, the -500 Ma high grade metamorphic age, which is ubiquitous in the LHC,is not documented in these rocks, because of either the extent sample collection area or allochtonous origin of the terrane.3. Data calibration for a X-ray fluorescence analyzer which was newly intstalled at NIPR was performed and geochemical studies at the Sor Rondane Mountains, Yamato Mountains and RC were carried out using the XRF.The results are compiled in the database at NIPR.In conclusion, the Pan-African event extensively affected these terranes much more than previously considered and we presume the collisional tectonics playd an important role. Further geochemical and isotopic examination of the metamorphic and plutonic rocks from these area is ongoing. Less

1。使用虾U-PB锆石年龄与SM-ND和RB-SR矿物质和整个岩石等速体年龄相结合，研究了Rayner配合物（RC）的变质和原始石材年龄。在RC中，我们确定了寒武纪事件的不同元古代。 -520-540 MA在沿海露头，-900-1000 MA的内陆露头中。这些年龄被认为代表了两个高级变质事件。 -780-800 Ma的另一组U-PB锆石年龄与先前报道的770 MA火成活性一致。我们打算进一步研究此事件的程度和性质。新的U-PB锆石数据表明，以前认为代表的区域的一部分代表了寒武纪（Pan-African）期间的proterokoic rayner络合物的西部边缘进行了高级变质，我们建议它是Lutzow-Holm-Holm Complex（LHC）的向东延续。2。已经执行了元trondhjemites和来自LHC的Hinode Cape Hinode的脑片片的RB-SR和SM-ND同位素研究……更多。考虑到初始比率和先前的锆石U -PB研究，我们得出的结论是-1000 MA年龄表明Trondhjemite的火成岩结晶时间。鞘岩片麻岩可能起源于中生古代材料，是trondhjemite侵入的宿主岩石。但是，在这些岩石中未记录在LHC中无处不在的-500 MA高级变质年龄，因为样品收集面积或地形的同种源3。进行了X射线荧光分析仪的数据校准，该X型荧光分析仪已在NIPR上进行了新插入，并在Sor Rondane山脉，大山脉，大和山脉进行地球化学研究，并使用XRF进行了结果。结果是在NIPR.IN的数据库中汇编的。角色。从这些区域进行的变质和丘脑岩的进一步地球化学和同位素检查正在进行中。较少的