Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels

Detalhes bibliográficos
Autor(a) principal: Galasso, Francesca
Data de Publicação: 2019
Outros Autores: Fernandes, Paulo, Montesi, Giovanni, Marques, João, Spina, Amália, Pereira, Zélia
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10400.9/3517
Resumo: ABSTRACT: Kerogen concentrates obtained from Lopingian (Late Permian) to Upper Triassic mudrock lithologies of seven coal exploration boreholes, drilled in the Moatize – Minjova Coal Basin (N'Condédzi sub-basin, Mozambique), were studied by means of vitrinite reflectance (VR), spore fluorescence and spore colour, in order to constrain the thermal history and basin evolution by organic maturation levels. VR increases with depth, indicating organic maturation related to sediment burial for most of the boreholes. Modelled VR data indicate a regional palaeogeothermal gradient between 35 and 40 °C/km. Lower Jurassic doleritic intrusions observed in three boreholes had only local thermal effects without affecting the regional palaeogeothermal gradient. Two boreholes located near the basin margin show high palaeogeothermal gradients suggesting thermal processes other than heating due to burial were involved. These processes may have involved hot diagenetic fluids circulating through fault zones and/or permeable lithologies, locally elevating geothermal gradients. Circulation of these fluids was induced by lithostatic pressure due to rapid rates of sedimentation. These high sedimentation rates lead to the accumulation of a thick succession (over 2000 m) of Lopingian (Late Permian) to Upper Triassic siliciclastic sediments. All the organic maturation indices measured and the age of the successions indicate that organic maturation occurred during or after Late Triassic times. However, the presence of reworked Permian palynomorphs into Upper Triassic sediments and the absence of Middle Triassic sediments indicate an exhumation and erosion of Permian strata in Middle Triassic times. The organic maturation levels of the reworked palynomorph population are considerably higher than the indigenous Upper Triassic population, indicating that they attained higher burial temperatures prior to being reworked.
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spelling Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levelsPaleogeografiaPalinostratigrafiaPalinomorfosMaturação orgânicaVitriniteKarooMoçambiqueABSTRACT: Kerogen concentrates obtained from Lopingian (Late Permian) to Upper Triassic mudrock lithologies of seven coal exploration boreholes, drilled in the Moatize – Minjova Coal Basin (N'Condédzi sub-basin, Mozambique), were studied by means of vitrinite reflectance (VR), spore fluorescence and spore colour, in order to constrain the thermal history and basin evolution by organic maturation levels. VR increases with depth, indicating organic maturation related to sediment burial for most of the boreholes. Modelled VR data indicate a regional palaeogeothermal gradient between 35 and 40 °C/km. Lower Jurassic doleritic intrusions observed in three boreholes had only local thermal effects without affecting the regional palaeogeothermal gradient. Two boreholes located near the basin margin show high palaeogeothermal gradients suggesting thermal processes other than heating due to burial were involved. These processes may have involved hot diagenetic fluids circulating through fault zones and/or permeable lithologies, locally elevating geothermal gradients. Circulation of these fluids was induced by lithostatic pressure due to rapid rates of sedimentation. These high sedimentation rates lead to the accumulation of a thick succession (over 2000 m) of Lopingian (Late Permian) to Upper Triassic siliciclastic sediments. All the organic maturation indices measured and the age of the successions indicate that organic maturation occurred during or after Late Triassic times. However, the presence of reworked Permian palynomorphs into Upper Triassic sediments and the absence of Middle Triassic sediments indicate an exhumation and erosion of Permian strata in Middle Triassic times. The organic maturation levels of the reworked palynomorph population are considerably higher than the indigenous Upper Triassic population, indicating that they attained higher burial temperatures prior to being reworked.ElsevierRepositório do LNEGGalasso, FrancescaFernandes, PauloMontesi, GiovanniMarques, JoãoSpina, AmáliaPereira, Zélia2020-12-07T10:31:55Z2019-01-01T00:00:00Z2019-01-01T00:00:00Z2024-12-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.9/3517engGalasso, F... [et.al.] - Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels. In: Journal of African Earth Sciences, 2019, Vol. 153, p. 219-2381464-343Xcv-prod-210722210.1016/j.jafrearsci.2019.02.0202-s2.0-85062984270info:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2022-09-06T12:29:07Zoai:repositorio.lneg.pt:10400.9/3517Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T15:36:43.862946Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
title Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
spellingShingle Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
Galasso, Francesca
Paleogeografia
Palinostratigrafia
Palinomorfos
Maturação orgânica
Vitrinite
Karoo
Moçambique
title_short Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
title_full Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
title_fullStr Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
title_full_unstemmed Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
title_sort Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels
author Galasso, Francesca
author_facet Galasso, Francesca
Fernandes, Paulo
Montesi, Giovanni
Marques, João
Spina, Amália
Pereira, Zélia
author_role author
author2 Fernandes, Paulo
Montesi, Giovanni
Marques, João
Spina, Amália
Pereira, Zélia
author2_role author
author
author
author
author
dc.contributor.none.fl_str_mv Repositório do LNEG
dc.contributor.author.fl_str_mv Galasso, Francesca
Fernandes, Paulo
Montesi, Giovanni
Marques, João
Spina, Amália
Pereira, Zélia
dc.subject.por.fl_str_mv Paleogeografia
Palinostratigrafia
Palinomorfos
Maturação orgânica
Vitrinite
Karoo
Moçambique
topic Paleogeografia
Palinostratigrafia
Palinomorfos
Maturação orgânica
Vitrinite
Karoo
Moçambique
description ABSTRACT: Kerogen concentrates obtained from Lopingian (Late Permian) to Upper Triassic mudrock lithologies of seven coal exploration boreholes, drilled in the Moatize – Minjova Coal Basin (N'Condédzi sub-basin, Mozambique), were studied by means of vitrinite reflectance (VR), spore fluorescence and spore colour, in order to constrain the thermal history and basin evolution by organic maturation levels. VR increases with depth, indicating organic maturation related to sediment burial for most of the boreholes. Modelled VR data indicate a regional palaeogeothermal gradient between 35 and 40 °C/km. Lower Jurassic doleritic intrusions observed in three boreholes had only local thermal effects without affecting the regional palaeogeothermal gradient. Two boreholes located near the basin margin show high palaeogeothermal gradients suggesting thermal processes other than heating due to burial were involved. These processes may have involved hot diagenetic fluids circulating through fault zones and/or permeable lithologies, locally elevating geothermal gradients. Circulation of these fluids was induced by lithostatic pressure due to rapid rates of sedimentation. These high sedimentation rates lead to the accumulation of a thick succession (over 2000 m) of Lopingian (Late Permian) to Upper Triassic siliciclastic sediments. All the organic maturation indices measured and the age of the successions indicate that organic maturation occurred during or after Late Triassic times. However, the presence of reworked Permian palynomorphs into Upper Triassic sediments and the absence of Middle Triassic sediments indicate an exhumation and erosion of Permian strata in Middle Triassic times. The organic maturation levels of the reworked palynomorph population are considerably higher than the indigenous Upper Triassic population, indicating that they attained higher burial temperatures prior to being reworked.
publishDate 2019
dc.date.none.fl_str_mv 2019-01-01T00:00:00Z
2019-01-01T00:00:00Z
2020-12-07T10:31:55Z
2024-12-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10400.9/3517
url http://hdl.handle.net/10400.9/3517
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Galasso, F... [et.al.] - Thermal history and basin evolution of the Moatize - Minjova Coal Basin (N'Condédzi sub-basin, Mozambique) constrained by organic maturation levels. In: Journal of African Earth Sciences, 2019, Vol. 153, p. 219-238
1464-343X
cv-prod-2107222
10.1016/j.jafrearsci.2019.02.020
2-s2.0-85062984270
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dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
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