Deformation-induced right-side-up pseudo-stratigraphy of the early Paleozoic Joseon Supergroup in the southeastern Danyang area, South Korea

IF 1 4区 地球科学 Q4 GEOSCIENCES, MULTIDISCIPLINARY Geosciences Journal Pub Date : 2024-04-18 DOI:10.1007/s12303-024-0008-2
Tae-Hoon Uhmb, Jin-Han Ree, Hyeong Soo Kim
{"title":"Deformation-induced right-side-up pseudo-stratigraphy of the early Paleozoic Joseon Supergroup in the southeastern Danyang area, South Korea","authors":"Tae-Hoon Uhmb, Jin-Han Ree, Hyeong Soo Kim","doi":"10.1007/s12303-024-0008-2","DOIUrl":null,"url":null,"abstract":"<p>The formations in the early Paleozoic Joseon Supergroup (mainly carbonates with subordinate siliciclastics) within the Taebaeksan Basin in the Danyang area, South Korea, show an apparent right-side-up homoclinal stratigraphy without repetition or omission of any formation, and it was therefore thought that the NW-dipping formation boundaries are primary depositional contacts. Our detailed examination revealed, however, that the formation boundaries are reverse-slip shear zones parallel to the second-generation foliation (<i>S</i><sub><i>2</i></sub>) crenulating transposed <i>S</i><sub>0</sub>//<i>S</i><sub>1</sub> foliation and that WNW-dipping bedding planes (<i>S</i><sub><i>0</i></sub>) are only locally preserved. The most penetrative regional planar structure in the area is the NNW-dipping first-generation foliation (<i>S</i><sub><i>1</i></sub>) that is defined by compositional layering and is parallel to the axial planes of isoclinal <i>F</i><sub><i>1</i></sub> folds. Isoclinal to close <i>F</i><sub><i>1</i></sub> folds occur on both the mesoscopic and macroscopic scale, whereas tight to close <i>F</i><sub><i>2</i></sub> folds occur locally only on the mesoscopic scale. <i>D</i><sub><i>1</i></sub> deformation presumably involved a NNW-SSE horizontal contraction and resulted in the buckle folding and transposition of <i>S</i><sub><i>0</i></sub>. <i>D</i><sub><i>2</i></sub> deformation involved a NW-SE contraction, probably at a high angle to the <i>S</i><sub>0</sub>//<i>S</i><sub>1</sub> transposed layers, and produced passive shear folding of <i>S</i><sub>0</sub>//<i>S</i><sub>1</sub> with <i>S</i><sub><i>2</i></sub> crenulation cleavages as discrete shear surfaces. Shearing deformation was strongly localized along some <i>S</i><sub><i>2</i></sub> foliation planes, resulting in reverse shear zones that represent the current ‘pseudo’-formation boundaries. Based on zircons U-Pb ages, we suggest that the Okdong Fault was initiated from an unconformable boundary between the Precambrian basement gneiss and overlying sediments of the Paleozoic Taebaeksan Basin, probably during the Middle Jurassic.</p>","PeriodicalId":12659,"journal":{"name":"Geosciences Journal","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geosciences Journal","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s12303-024-0008-2","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0

Abstract

The formations in the early Paleozoic Joseon Supergroup (mainly carbonates with subordinate siliciclastics) within the Taebaeksan Basin in the Danyang area, South Korea, show an apparent right-side-up homoclinal stratigraphy without repetition or omission of any formation, and it was therefore thought that the NW-dipping formation boundaries are primary depositional contacts. Our detailed examination revealed, however, that the formation boundaries are reverse-slip shear zones parallel to the second-generation foliation (S2) crenulating transposed S0//S1 foliation and that WNW-dipping bedding planes (S0) are only locally preserved. The most penetrative regional planar structure in the area is the NNW-dipping first-generation foliation (S1) that is defined by compositional layering and is parallel to the axial planes of isoclinal F1 folds. Isoclinal to close F1 folds occur on both the mesoscopic and macroscopic scale, whereas tight to close F2 folds occur locally only on the mesoscopic scale. D1 deformation presumably involved a NNW-SSE horizontal contraction and resulted in the buckle folding and transposition of S0. D2 deformation involved a NW-SE contraction, probably at a high angle to the S0//S1 transposed layers, and produced passive shear folding of S0//S1 with S2 crenulation cleavages as discrete shear surfaces. Shearing deformation was strongly localized along some S2 foliation planes, resulting in reverse shear zones that represent the current ‘pseudo’-formation boundaries. Based on zircons U-Pb ages, we suggest that the Okdong Fault was initiated from an unconformable boundary between the Precambrian basement gneiss and overlying sediments of the Paleozoic Taebaeksan Basin, probably during the Middle Jurassic.

查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
韩国丹阳东南部早古生代朝鲜超群的变形诱导右旋假地层学
韩国丹阳地区太白山盆地内早古生代朝鲜超群的地层(主要为碳酸盐岩,其次为硅质岩)显示出明显的右旋同向地层,没有重复或遗漏任何地层,因此人们认为西北倾的地层边界是主要的沉积接触点。然而,我们的详细研究发现,地层边界是与第二代折线(S2)平行的反向滑动剪切带,该剪切带呈圆弧状转置 S0//S1 折线,仅在局部地区保留了向西北倾斜的基底面(S0)。该地区最具穿透力的区域平面结构是北西倾第一代褶皱(S1),它是由成分层理确定的,与等轴F1褶皱的轴向平面平行。等卷至闭合的F1褶皱出现在中观和宏观尺度上,而紧密至闭合的F2褶皱仅出现在局部中观尺度上。D1 变形可能涉及 NNW-SSE 水平收缩,并导致 S0 的倒扣褶皱和转位。D2变形涉及西北-东南收缩,可能与S0//S1转位层呈高角度,并产生了S0//S1的被动剪切褶皱,S2的齿状裂隙成为离散的剪切面。剪切变形沿着一些 S2 褶皱平面强烈局部化,形成了代表当前 "伪 "构造边界的反向剪切带。根据锆石的 U-Pb 年龄,我们认为 Okdong 断层是由前寒武纪基底片麻岩与古生代太白山盆地上覆沉积物之间的不整合边界引发的,可能发生在中侏罗世。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 去求助
来源期刊
Geosciences Journal
Geosciences Journal 地学-地球科学综合
CiteScore
2.70
自引率
8.30%
发文量
33
审稿时长
6 months
期刊介绍: Geosciences Journal opens a new era for the publication of geoscientific research articles in English, covering geology, geophysics, geochemistry, paleontology, structural geology, mineralogy, petrology, stratigraphy, sedimentology, environmental geology, economic geology, petroleum geology, hydrogeology, remote sensing and planetary geology.
期刊最新文献
Study and application of wide-azimuth seismic anisotropy analysis and correction in shale reservoir in Gulong Sag, Songliao Basin, China First evidence of magmatic Ni-Cu sulfides and hydrothermal Zn mineralization in Jumun Island, central-western Korean peninsula He-Ar isotopic signatures of the Mesozoic granitoids in South Korea: implications for genesis of the granitic magma and crustal evolution in NE continental margin of the Eurasian plate Segmentation geometry of strike-slip fault systems in slow-deforming regions: a proposed method and case study of the Yangsan Fault, South Korea Age and relative uplift of marine terraces controlled by fault activities along the eastern coast of Korea
×
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
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 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 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1