Turki K. Alshammasi, Sian L. Evans, Christopher A.-L. Jackson
{"title":"墨西哥湾北部绿峡谷地区树冠推进和缩短过程中的盐焊接","authors":"Turki K. Alshammasi, Sian L. Evans, Christopher A.-L. Jackson","doi":"10.1306/01192321170","DOIUrl":null,"url":null,"abstract":"Welds form due to tectonically induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few published examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding and to test analytical models of the underlying mechanics. In this study, we integrate three-dimensional seismic reflection and borehole data from the Green Canyon area of the northern Gulf of Mexico, United States, to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show that although appearing complete in seismic reflection data, the weld contains 124 ft (38 m) of relatively pure halite. This thickness is consistent with the predictions of analytical models and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units, if originally present, are typically stranded within the deeper, autochthonous level trapped in primary welds or near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.","PeriodicalId":7124,"journal":{"name":"AAPG Bulletin","volume":"22 1","pages":""},"PeriodicalIF":2.7000,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Salt welding during canopy advance and shortening in the Green Canyon area, northern Gulf of Mexico\",\"authors\":\"Turki K. Alshammasi, Sian L. Evans, Christopher A.-L. Jackson\",\"doi\":\"10.1306/01192321170\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Welds form due to tectonically induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few published examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding and to test analytical models of the underlying mechanics. In this study, we integrate three-dimensional seismic reflection and borehole data from the Green Canyon area of the northern Gulf of Mexico, United States, to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show that although appearing complete in seismic reflection data, the weld contains 124 ft (38 m) of relatively pure halite. This thickness is consistent with the predictions of analytical models and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units, if originally present, are typically stranded within the deeper, autochthonous level trapped in primary welds or near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.\",\"PeriodicalId\":7124,\"journal\":{\"name\":\"AAPG Bulletin\",\"volume\":\"22 1\",\"pages\":\"\"},\"PeriodicalIF\":2.7000,\"publicationDate\":\"2023-12-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"AAPG Bulletin\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1306/01192321170\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"AAPG Bulletin","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1306/01192321170","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Salt welding during canopy advance and shortening in the Green Canyon area, northern Gulf of Mexico
Welds form due to tectonically induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few published examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding and to test analytical models of the underlying mechanics. In this study, we integrate three-dimensional seismic reflection and borehole data from the Green Canyon area of the northern Gulf of Mexico, United States, to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show that although appearing complete in seismic reflection data, the weld contains 124 ft (38 m) of relatively pure halite. This thickness is consistent with the predictions of analytical models and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units, if originally present, are typically stranded within the deeper, autochthonous level trapped in primary welds or near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.
期刊介绍:
While the 21st-century AAPG Bulletin has undergone some changes since 1917, enlarging to 8 ½ x 11” size to incorporate more material and being published digitally as well as in print, it continues to adhere to the primary purpose of the organization, which is to advance the science of geology especially as it relates to petroleum, natural gas, other subsurface fluids, and mineral resources.
Delivered digitally or in print monthly to each AAPG Member as a part of membership dues, the AAPG Bulletin is one of the most respected, peer-reviewed technical journals in existence, with recent issues containing papers focused on such topics as the Middle East, channel detection, China, permeability, subseismic fault prediction, the U.S., and Africa.