冲击岩石学和数值建模对南非莫洛克文(Morokweng)撞击结构的形态和大小的制约因素

IF 2.2 4区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS
Roger L. Gibson, S'lindile S. Wela, Auriol S. P. Rae, Marco A. G. Andreoli
{"title":"冲击岩石学和数值建模对南非莫洛克文(Morokweng)撞击结构的形态和大小的制约因素","authors":"Roger L. Gibson,&nbsp;S'lindile S. Wela,&nbsp;Auriol S. P. Rae,&nbsp;Marco A. G. Andreoli","doi":"10.1111/maps.14275","DOIUrl":null,"url":null,"abstract":"<p>The 369 m deep M4 drill hole, located ~18 km NNW of the center of the 146 Ma Morokweng impact structure (MIS), intersects shocked Archean granitoid gneisses and subsidiary dolerite intrusions that are cut by faults, cataclasites and mm- to m-wide suevitic and pseudotachylitic breccia dikes. The shock features in quartz in the gneisses and breccia dikes include decorated planar deformation features (PDFs), planar fractures, feather features, and toasting. Other minerals show features that may be shock-related, such as multiple sets of planar features and alternate twin ladder structures in feldspars, kink bands in biotite, and planar features in titanite, apatite, and zircon; however, these are variably annealed and/or overprinted by hydrothermal alteration effects, and confirmation of their origin awaits further study. Universal Stage measurements of PDF sets in quartz from 12 gneissic target rocks and from lithic and mineral clasts in three suevitic and three pseudotachylitic breccia dikes reveal four dominant sets: (0001), {<span></span><math>\n <mrow>\n <mn>10</mn>\n <mover>\n <mn>1</mn>\n <mo>¯</mo>\n </mover>\n <mn>3</mn>\n </mrow></math>}, {<span></span><math>\n <mrow>\n <mn>10</mn>\n <mover>\n <mn>1</mn>\n <mo>¯</mo>\n </mover>\n <mn>4</mn>\n </mrow></math>} and {<span></span><math>\n <mrow>\n <mn>10</mn>\n <mover>\n <mn>1</mn>\n <mo>¯</mo>\n </mover>\n <mn>2</mn>\n </mrow></math>}. Based on these observations, the average peak shock pressure in these rocks is estimated at ≤16 GPa, which supports the original proximity (within one transient cavity radius) of these rocks to the point of impact. No discernible depth-dependent shock attenuation was noted in the core. These shock levels and the elevated structural position of the rocks in the M4 core relative to the impact melt sheet intersected in drill holes closer to the center of the MIS suggest that the M4 lithologies represent part of the parautochthonous peak ring volume that subsequently experienced 1.5–2 km of post-impact erosion before it was buried beneath younger sediments. Numerical modeling using the iSALE-2D code suggests that the original Morokweng crater had a rim-to-rim diameter of between 70 and 80 km, and that the rocks in the M4 core were originally located at a depth of 7–8 km and a radial distance of 8–9 km from the point of impact.</p>","PeriodicalId":18555,"journal":{"name":"Meteoritics & Planetary Science","volume":"59 12","pages":"3250-3281"},"PeriodicalIF":2.2000,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14275","citationCount":"0","resultStr":"{\"title\":\"Shock petrographic and numerical modeling constraints on the morphology and size of the Morokweng impact structure, South Africa\",\"authors\":\"Roger L. Gibson,&nbsp;S'lindile S. Wela,&nbsp;Auriol S. P. Rae,&nbsp;Marco A. G. Andreoli\",\"doi\":\"10.1111/maps.14275\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The 369 m deep M4 drill hole, located ~18 km NNW of the center of the 146 Ma Morokweng impact structure (MIS), intersects shocked Archean granitoid gneisses and subsidiary dolerite intrusions that are cut by faults, cataclasites and mm- to m-wide suevitic and pseudotachylitic breccia dikes. The shock features in quartz in the gneisses and breccia dikes include decorated planar deformation features (PDFs), planar fractures, feather features, and toasting. Other minerals show features that may be shock-related, such as multiple sets of planar features and alternate twin ladder structures in feldspars, kink bands in biotite, and planar features in titanite, apatite, and zircon; however, these are variably annealed and/or overprinted by hydrothermal alteration effects, and confirmation of their origin awaits further study. Universal Stage measurements of PDF sets in quartz from 12 gneissic target rocks and from lithic and mineral clasts in three suevitic and three pseudotachylitic breccia dikes reveal four dominant sets: (0001), {<span></span><math>\\n <mrow>\\n <mn>10</mn>\\n <mover>\\n <mn>1</mn>\\n <mo>¯</mo>\\n </mover>\\n <mn>3</mn>\\n </mrow></math>}, {<span></span><math>\\n <mrow>\\n <mn>10</mn>\\n <mover>\\n <mn>1</mn>\\n <mo>¯</mo>\\n </mover>\\n <mn>4</mn>\\n </mrow></math>} and {<span></span><math>\\n <mrow>\\n <mn>10</mn>\\n <mover>\\n <mn>1</mn>\\n <mo>¯</mo>\\n </mover>\\n <mn>2</mn>\\n </mrow></math>}. Based on these observations, the average peak shock pressure in these rocks is estimated at ≤16 GPa, which supports the original proximity (within one transient cavity radius) of these rocks to the point of impact. No discernible depth-dependent shock attenuation was noted in the core. These shock levels and the elevated structural position of the rocks in the M4 core relative to the impact melt sheet intersected in drill holes closer to the center of the MIS suggest that the M4 lithologies represent part of the parautochthonous peak ring volume that subsequently experienced 1.5–2 km of post-impact erosion before it was buried beneath younger sediments. Numerical modeling using the iSALE-2D code suggests that the original Morokweng crater had a rim-to-rim diameter of between 70 and 80 km, and that the rocks in the M4 core were originally located at a depth of 7–8 km and a radial distance of 8–9 km from the point of impact.</p>\",\"PeriodicalId\":18555,\"journal\":{\"name\":\"Meteoritics & Planetary Science\",\"volume\":\"59 12\",\"pages\":\"3250-3281\"},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2024-11-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1111/maps.14275\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Meteoritics & Planetary Science\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1111/maps.14275\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Meteoritics & Planetary Science","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/maps.14275","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0

摘要

本文章由计算机程序翻译,如有差异,请以英文原文为准。

Shock petrographic and numerical modeling constraints on the morphology and size of the Morokweng impact structure, South Africa

Shock petrographic and numerical modeling constraints on the morphology and size of the Morokweng impact structure, South Africa

The 369 m deep M4 drill hole, located ~18 km NNW of the center of the 146 Ma Morokweng impact structure (MIS), intersects shocked Archean granitoid gneisses and subsidiary dolerite intrusions that are cut by faults, cataclasites and mm- to m-wide suevitic and pseudotachylitic breccia dikes. The shock features in quartz in the gneisses and breccia dikes include decorated planar deformation features (PDFs), planar fractures, feather features, and toasting. Other minerals show features that may be shock-related, such as multiple sets of planar features and alternate twin ladder structures in feldspars, kink bands in biotite, and planar features in titanite, apatite, and zircon; however, these are variably annealed and/or overprinted by hydrothermal alteration effects, and confirmation of their origin awaits further study. Universal Stage measurements of PDF sets in quartz from 12 gneissic target rocks and from lithic and mineral clasts in three suevitic and three pseudotachylitic breccia dikes reveal four dominant sets: (0001), { 10 1 ¯ 3 }, { 10 1 ¯ 4 } and { 10 1 ¯ 2 }. Based on these observations, the average peak shock pressure in these rocks is estimated at ≤16 GPa, which supports the original proximity (within one transient cavity radius) of these rocks to the point of impact. No discernible depth-dependent shock attenuation was noted in the core. These shock levels and the elevated structural position of the rocks in the M4 core relative to the impact melt sheet intersected in drill holes closer to the center of the MIS suggest that the M4 lithologies represent part of the parautochthonous peak ring volume that subsequently experienced 1.5–2 km of post-impact erosion before it was buried beneath younger sediments. Numerical modeling using the iSALE-2D code suggests that the original Morokweng crater had a rim-to-rim diameter of between 70 and 80 km, and that the rocks in the M4 core were originally located at a depth of 7–8 km and a radial distance of 8–9 km from the point of impact.

求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
Meteoritics & Planetary Science
Meteoritics & Planetary Science 地学天文-地球化学与地球物理
CiteScore
3.90
自引率
31.80%
发文量
121
审稿时长
3 months
期刊介绍: First issued in 1953, the journal publishes research articles describing the latest results of new studies, invited reviews of major topics in planetary science, editorials on issues of current interest in the field, and book reviews. The publications are original, not considered for publication elsewhere, and undergo peer-review. The topics include the origin and history of the solar system, planets and natural satellites, interplanetary dust and interstellar medium, lunar samples, meteors, and meteorites, asteroids, comets, craters, and tektites. Our authors and editors are professional scientists representing numerous disciplines, including astronomy, astrophysics, physics, geophysics, chemistry, isotope geochemistry, mineralogy, earth science, geology, and biology. MAPS has subscribers in over 40 countries. Fifty percent of MAPS'' readers are based outside the USA. The journal is available in hard copy and online.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信