Jean-Baptiste P. Koehl, Gard Christophersen, M. Collombin, Christoffer Taule, Eirik M.B. Stokmo, Lis Allaart
{"title":"斯匹次卑尔根中部Billefjorden地区元古界基底中受西北西东向构造颗粒控制的泥盆纪-密西西比期断裂","authors":"Jean-Baptiste P. Koehl, Gard Christophersen, M. Collombin, Christoffer Taule, Eirik M.B. Stokmo, Lis Allaart","doi":"10.1344/geologicaacta2023.21.7","DOIUrl":null,"url":null,"abstract":"In Billefjorden, central Spitsbergen, Devonian collapse and Carboniferous rift-related sedimentary strata were deposited unconformably over Proterozoic basement rocks displaying well developed N-S-trending Caledonian grain. Caledonian structures and fabrics are thought to have controlled the location and trend of subsequent Devonian and Carboniferous basin-bounding faults like the Billefjorden fault zone and Lemströmfjellet–Løvehovden fault. However, fieldwork and interpretation of aerial photographs in Proterozoic basement rocks reveal the existence of steep, abundant, WNW-ESE-striking brittle faults that are sub-orthogonal to known major Caledonian and post-Caledonian structures in Billefjorden, but that do not extend into adjacent-overlying, rift-related, Pennsylvanian rocks of the Gipsdalen Group. Structural analysis of field data and aerial photographs suggest that WNW-ESE-striking faults in basement rocks in Billefjorden formed as (sinistral) strike-slip and normal faults during Devonian-Mississippian extension in agreement with previously inferred models of sinistral transtension. The abundance of these faults suggest that their formation was controlled by analogously trending, preexisting structural grain (planar anisotropies) at depth, and their pronounced WNW-ESE strike suggest that the strike of preexisting anisotropies were comparable to recently identified, crustal-scale, WNW-ESE-striking Timanian thrust systems in Svalbard and the northern Barents Sea.","PeriodicalId":55107,"journal":{"name":"Geologica Acta","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Devonian-Mississippian faulting controlled by WNW-ESE-striking structural grain in Proterozoic basement rocks in Billefjorden, central Spitsbergen\",\"authors\":\"Jean-Baptiste P. Koehl, Gard Christophersen, M. Collombin, Christoffer Taule, Eirik M.B. Stokmo, Lis Allaart\",\"doi\":\"10.1344/geologicaacta2023.21.7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"In Billefjorden, central Spitsbergen, Devonian collapse and Carboniferous rift-related sedimentary strata were deposited unconformably over Proterozoic basement rocks displaying well developed N-S-trending Caledonian grain. Caledonian structures and fabrics are thought to have controlled the location and trend of subsequent Devonian and Carboniferous basin-bounding faults like the Billefjorden fault zone and Lemströmfjellet–Løvehovden fault. However, fieldwork and interpretation of aerial photographs in Proterozoic basement rocks reveal the existence of steep, abundant, WNW-ESE-striking brittle faults that are sub-orthogonal to known major Caledonian and post-Caledonian structures in Billefjorden, but that do not extend into adjacent-overlying, rift-related, Pennsylvanian rocks of the Gipsdalen Group. Structural analysis of field data and aerial photographs suggest that WNW-ESE-striking faults in basement rocks in Billefjorden formed as (sinistral) strike-slip and normal faults during Devonian-Mississippian extension in agreement with previously inferred models of sinistral transtension. The abundance of these faults suggest that their formation was controlled by analogously trending, preexisting structural grain (planar anisotropies) at depth, and their pronounced WNW-ESE strike suggest that the strike of preexisting anisotropies were comparable to recently identified, crustal-scale, WNW-ESE-striking Timanian thrust systems in Svalbard and the northern Barents Sea.\",\"PeriodicalId\":55107,\"journal\":{\"name\":\"Geologica Acta\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2023-07-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geologica Acta\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1344/geologicaacta2023.21.7\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geologica Acta","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1344/geologicaacta2023.21.7","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOLOGY","Score":null,"Total":0}
Devonian-Mississippian faulting controlled by WNW-ESE-striking structural grain in Proterozoic basement rocks in Billefjorden, central Spitsbergen
In Billefjorden, central Spitsbergen, Devonian collapse and Carboniferous rift-related sedimentary strata were deposited unconformably over Proterozoic basement rocks displaying well developed N-S-trending Caledonian grain. Caledonian structures and fabrics are thought to have controlled the location and trend of subsequent Devonian and Carboniferous basin-bounding faults like the Billefjorden fault zone and Lemströmfjellet–Løvehovden fault. However, fieldwork and interpretation of aerial photographs in Proterozoic basement rocks reveal the existence of steep, abundant, WNW-ESE-striking brittle faults that are sub-orthogonal to known major Caledonian and post-Caledonian structures in Billefjorden, but that do not extend into adjacent-overlying, rift-related, Pennsylvanian rocks of the Gipsdalen Group. Structural analysis of field data and aerial photographs suggest that WNW-ESE-striking faults in basement rocks in Billefjorden formed as (sinistral) strike-slip and normal faults during Devonian-Mississippian extension in agreement with previously inferred models of sinistral transtension. The abundance of these faults suggest that their formation was controlled by analogously trending, preexisting structural grain (planar anisotropies) at depth, and their pronounced WNW-ESE strike suggest that the strike of preexisting anisotropies were comparable to recently identified, crustal-scale, WNW-ESE-striking Timanian thrust systems in Svalbard and the northern Barents Sea.
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