• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>South African Journal of Geology: Being the Transaction of the Geological Society of South African: Syndie die Verhandelinge van die Geologiese Vereniging van Suid-Afrika >Stratigraphy and Geochemistry of the Goedgenoeg and Makwassie Formations, Ventersdorp Supergroup, in the Bothaville area of South Africa
【24h】

Stratigraphy and Geochemistry of the Goedgenoeg and Makwassie Formations, Ventersdorp Supergroup, in the Bothaville area of South Africa

机译：Stratigraphy和地球化学的良好和Makwassie地层，Ventersdorp Supergroup，位于南非的Bothaville地区

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Neoarchaean Ventersdorp Supergroup represents a fully evolved bimodal volcano-sedimentary succession on the Kaapvaal Craton. Stratigraphic information was mainly derived from exploration drilling for gold in the underlying Witwatersrand Supergroup. Following the basal flood basalts of the Klipriviersberg Group, the Platberg Group mostly comprises extensive and voluminous intermediate to felsic volcanics of the Goedgenoeg and Makwassie Formations. Detailed stratigraphic and geochemical reports of these two formations were previously mostly restricted to the so-called Bothaville gap, between the Free State and Klerksdorp Gold Fields. The lower part of the Goedgenoeg Formation succession consists of non-porphyritic andesitic lava flows, followed upwards by dacitic phenocryst-rich feldspar porphyries. The basal lava flows are frequently interbedded with sedimentary rocks of the underlying Kameeldoorns Formation. Andesitic lava-flow units persist upwards, occurring interbedded with the Goedgenoeg Formation feldspar porphyries. The feldspar porphyries originated as ash flows; most are highly welded. The upper feldspar porphyries in the succession are absent in large parts of the Bothaville gap. The overlying Makwassie Formation consists of quartz porphyries, also with intermittent interbedded mafic lava units throughout the succession. The upper part of the succession is composed of phenocryst-rich crystal tuffs, only preserved over limited areas of the Bothaville gap. The quartz porphyries are highly welded, high-temperature ash flows with individual flows of tens of metres in thickness, typically separated by thin tuffs and sediments. The Goedgenoeg and Makwassie interbedded andesitic lavas have similar geochemical composition (the geochemical composition of the overlying Rietgat Formation lavas is also similar to that). The Goedgenoeg dacitic feldspar porphyries are separated into two geochemical groups: a lower high-Zr group and an upper low-Zr group. The Makwassi
机译：NeoAthaean Ventersdorp Supergroup代表了Kaapvaal Craton上的完全发展的双峰火山沉积连续。地层信息主要来自潜在的Witwatersrand Superrom中的黄金勘探钻探。在Klipriiviersberg组的基础洪水沼气之后，Platberg组主要包括Goedgenoeg和Makwassie地层的肠道肠蠕动的广泛且大量的中间体。这些两个地层的详细地层和地球化学报告以前受到自由州和Klerksdorp金田之间所谓的Spothaville差距。 Goedgenoeg形成继承的下半部分包括非卟啉和岩熔岩流动，由富巨虫富含富含的富含富巨裂的长石卟啉。基底熔岩流量经常与底层kameeldorns形成的沉积岩石堵塞。安耶捷熔岩流量单位坚持向上，随着Goedgenoeg形成长石卟啉骨灰覆盖。长石卟啉源于灰烬;大多数都是高焊接的。在佩拉维尔差距的大部分中，继承中的上部长石卟啉不存在。覆盖的Makwassie形成包括石英斑岩，也包括间歇性互联的MAFIC LAVA单元。连续的上部由富有的富苯基杂交的水晶牙龈组成，仅保存在Hothaville间隙的有限区域上。石英卟啉是高度焊接的，高温灰度流动，厚度的各个流量，通常用薄的凝灰岩和沉积物分开。 Goedgenoeg和Makwassie互粘土的山羊座具有类似的地球化学组成（覆盖的Rietgat形成熔岩的地球化学组成也与此类似）。 Goedgenoeg Dacitic Feldspar卟啉卟啉分为两个地球化学基团：较低的高Zr组和上低Zr组。 makwassi.

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号