{"title":"Volcaniclastic rocks and reconstruction of a volcanosedimentary paleoenvironment in Campos Basin, SE Brazil","authors":"Yara Veloso Magalhães Frank, S. Valente","doi":"10.1590/2317-4889202320220089","DOIUrl":null,"url":null,"abstract":"Santonian-Campanian tuffaceous siltstone, epiclastic siltstone, arkose, and fossiliferous mudstone occur in a 45-m-thick section of well 1-BR-SA-37-RJS drilled in the southern Campos Basin, offshore SE Brazil. Well log data and petrographic and lithogeochemical data obtained from cutting samples were used to propose a schematic model of the volcano’s sedimentary paleoenvironment. The volcaniclasts in the tuffaceous siltstone and epiclastic siltstone are scoria basalts, typical of spatter cones associated with monogenetic fields worldwide. The combination of these features with the petrographic ones of the arkoses found in the same well interval is likely to be related to volcaniclastic processes taking place on the continental shelf. Ratios between the immobile trace elements of the volcaniclastic rocks can be explained by mixing between sources in the upper continental crust adjacent to southern Campos and the scoria basalts extruded in the monogenetic fields. The little differentiated, olivine-rich basalts extruded from the scoria and spatter cones suggest a rising asthenosphere mantle extending from hundreds of kilometers eastwards till southern Campos in the Santonian-Campanian. This may have resulted in regional discordances in the Santonian, both in the Campos and Santos basins, and also places the petroleum systems in the southern Campos Basin under the thermal influence of such a rising asthenosphere in the Santonian-Campanian.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"30 1","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Brazilian Journal of Geology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1590/2317-4889202320220089","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Santonian-Campanian tuffaceous siltstone, epiclastic siltstone, arkose, and fossiliferous mudstone occur in a 45-m-thick section of well 1-BR-SA-37-RJS drilled in the southern Campos Basin, offshore SE Brazil. Well log data and petrographic and lithogeochemical data obtained from cutting samples were used to propose a schematic model of the volcano’s sedimentary paleoenvironment. The volcaniclasts in the tuffaceous siltstone and epiclastic siltstone are scoria basalts, typical of spatter cones associated with monogenetic fields worldwide. The combination of these features with the petrographic ones of the arkoses found in the same well interval is likely to be related to volcaniclastic processes taking place on the continental shelf. Ratios between the immobile trace elements of the volcaniclastic rocks can be explained by mixing between sources in the upper continental crust adjacent to southern Campos and the scoria basalts extruded in the monogenetic fields. The little differentiated, olivine-rich basalts extruded from the scoria and spatter cones suggest a rising asthenosphere mantle extending from hundreds of kilometers eastwards till southern Campos in the Santonian-Campanian. This may have resulted in regional discordances in the Santonian, both in the Campos and Santos basins, and also places the petroleum systems in the southern Campos Basin under the thermal influence of such a rising asthenosphere in the Santonian-Campanian.
期刊介绍:
The Brazilian Journal of Geology (BJG) is a quarterly journal published by the Brazilian Geological Society with an electronic open access version that provides an in-ternacional medium for the publication of original scientific work of broad interest concerned with all aspects of the earth sciences in Brazil, South America, and Antarctica, in-cluding oceanic regions adjacent to these regions. The BJG publishes papers with a regional appeal and more than local significance in the fields of mineralogy, petrology, geochemistry, paleontology, sedimentology, stratigraphy, structural geology, tectonics, neotectonics, geophysics applied to geology, volcanology, metallogeny and mineral deposits, marine geology, glaciology, paleoclimatology, geochronology, biostratigraphy, engineering geology, hydrogeology, geological hazards and remote sensing, providing a niche for interdisciplinary work on regional geology and Earth history.
The BJG publishes articles (including review articles), rapid communications, articles with accelerated review processes, editorials, and discussions (brief, objective and concise comments on recent papers published in BJG with replies by authors).
Manuscripts must be written in English. Companion papers will not be accepted.