The Fazenda Largo off-craton kimberlites of Piauí State, Brazil

Kaminsky, Felix V.; Sablukov, S. M.; Sablukova, L. I.; Zakharchenko, Olga D.

doi:10.1016/j.jsames.2009.06.003

Cited by 9 publications

(12 citation statements)

References 13 publications

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“…Similarly, although our rotations suggest that the lineament would have experienced extension across its axis, there is no evidence for concomitant sedimentary basin formation. The presence of Cretaceous kimberlites and other alkaline volcanic centers along the lineament's length can, on the other hand, be seen as consistent with small degrees of partial melting during limited extensional thinning of the lithosphere [ Sonoki and Garda , ; Silva et al ., ; Pereria and Fuck , ; Kaminsky et al ., ]. Similar interpretations can be made concerning alkaline volcanism along lineaments in South America such as the Ponta Grossa and Ponta Porã arches [ Gomes et al ., , ] and Asunción Rift [ Velázquez et al ., ] and in Africa, such as the Lucapa graben [ De Boorder , ; Pereira et al ., ].…”

Section: Discussionsupporting

confidence: 64%

Constraining South Atlantic growth with seafloor spreading data

2014

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Recent models of South Atlantic opening history focus on early plate divergence by incorporating intracontinental deformation, which is poorly constrained. Aiming to avoid the uncertainties in this approach, we model the entire divergence history with a joint inversion for seafloor spreading data. For this history, the pre-Campanian motion parameters are the first to feature formal uncertainty estimates. We date the onset of spreading at 138 Ma, with movement along intracontinental accommodation zones leading to the assembly of South America by 123 Ma and Africa by 106 Ma. Part of the ridge in the Agulhas Basin jumped westward soon afterward toward the Bouvet plume, initiating the motion of a short-lived Malvinas Plate. The NE Georgia and Maud rises and Agulhas Plateau formed as a large igneous province over the plume. Farther north, part of the ridge jumped eastward toward the Tristan plume around 94-93 Ma but seems not to have resulted in independent plate motion. Our results show that the South Atlantic grew by diachronous breakup of continents on just two plates. Cretaceous intracontinental deformation in South America and Africa can be interpreted in terms of the accommodation of stress associated with northward propagation of this process. The pattern of accommodation is usually envisaged as focusing all of the strain in narrow belts. With our rotations, a commonly used set of such belts accounts instead for just 42-67% of the implied total strain. We suggest that the remainder was accommodated at all scales within the continental interiors and the extended continental margins.

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Section: Discussionsupporting

confidence: 64%

Constraining South Atlantic growth with seafloor spreading data

2014

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“…In the Sao Francisco craton, the known kimberlites have Neoproterozoic ages [51] but most kimberlites occur in off craton settings [52] and are common of low diamond grade.…”

Section: South Americamentioning

confidence: 99%

Thermobarometry of Diamond Inclusions: Evidence Mantle Evolution beneath Siberian Craton and Archean Cratons Worldwide.

Ashchepkov¹,

Logvinova²,

Spetsius³

et al. 2021

Preprint

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Thermobarometric calculations for mineral inclusions in diamonds provide a systematic comparison of PTXFO2 conditions for different cratons worldwide, using a database of 4440 mineral EPMA analyses. Beneath all cratons, the cold branch of the mantle geotherm (35-32 mWm−2) relates to the sub-Ca garnets and rarely omphacitic diamond inclusions, referring to major continental growth events in Archean. High-temperature plume-related geotherms are common in Proterozoic kimberlites such as Premier, Mesozoic – Roberts Victor etc. and are common in Slave and Siberian cratons. In mobile belts: Limpopo, Magondi, Ural Ural, Khapchan belts and in the marginal parts of cratons like Kimberly Australia pyroxenitic and eclogitic pyroxenes and garnets prevail. The pyropes in the mobile belts are more Fe- and Ca-rich, in central parts of cratons, the peridotitic associations with sub- Ca pyropes prevail. The accretionary complexes like Khapchan and Magondi belts a thick eclogite-pyroxenite lens is highly diamondiferous. Comparison by minerals shows that the PT estimates for clinopyroxenes and orthopyroxene from peridotites and eclogites are representing mainly the middle part of the sub-lithospheric mantle while garnets gives more high-pressure estimates. refer to eclogites and reflect the processes of the differentiation during migration of partial melts. This produces the trends of joint decreasing Mg’ and pressures. The PT for the chromites reflect conditions just above the lithosphere-asthenosphere boundary and mainly were formed due to interaction with the hydrous plume protokimberlite melts. Archean diamond inclusions from Wawa province Canada are represented by Ca-enrich pyropes giving low-temperature conditions. Inclusions from younger kimberlites in Superior and Slave (and Siberian and East European ) cratons show complex high-temperature geotherms due to plumes influence. Peridotite garnets beneath the Amazonian craton indicate complex layering in the lithosphere base and a pyroxene layer in the middle part of SCLM. Diamond inclusions from the Kimberley craton of Australia show the greatest variations in the temperatures and composition.

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“…Na Província Parnaíba, ocorrem ainda intrusões kimberlíticas controladas pelo LTB, como as de Redondão, Gilbués e Fazenda Largo (Kaminsky et al 2009).…”

Section: Consideram O Lineamentounclassified

Tectônica intraplaca e deformação sinsedimentar induzida por abalos sísmicos: o Lineamento Transbrasiliano e estruturas relacionadas na Província Parnaíba, Brasil

Chamani¹

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Concluir uma dissertação de mestrado é um processo longo e complexo, e ninguém chega ao final sem a ajuda de muita gente. Toda lista de agradecimentos tem no fundo uma dose de deselegância: sempre deixamos inadvertidamente muita gente que nos ajudou de fora. Por isso, peço desculpas antecipadas a todos àqueles que eu porventura omitir aqui. Um dos grandes prazeres da geologia como ciência são os papos de boteco; conversamos várias coisas, é claro, mas a própria geologia é um tema recorrente nessas conversas, e esses papos muitas vezes sobrevivem à ressaca e se desenvolvem em coisas úteis. Seria impossível enumerar todo mundo com que eu tive conversas interessantes em bares, festas e defesas de mestrados ou doutorados nesses vinte e tantos anos de geologia, mas vou lembrar aqui especialmente algumas pessoas com quem eu tive várias conversas pertinentes aos temas desta tese, como os colegas Melado, Borboleta, Falcon, Frutinha e outros que eu certamente estou esquecendo. Agradecimentos especiais ao Sagüi, pelas coordenadas de alguns afloramentos e pontos de interesse na área (entre eles o essencial afloramento de Novo Acordo e os não menos essenciais bares do Totó e do Camilo); ao Guano, pela grande força que me deu nos trabalhos de campo e de escritório; e ao Marciano, nosso tão competente piloto nos trabalhos de campo. Agradeço também à Ana Góes, que me deu algumas informações valiosas à respeito da Província Parnaíba, que ela redefiniu e conhece tão bem. Agradeço ao CNPQ pela concessão da bolsa de mestrado. Agradecimentos muito especiais ao Riccomini, não só por ter sido um excelente orientador e companheiro de campo, mas pela paciência que demonstrou ao esperar por quase vinte anos que eu enfim me formasse para fazer o mestrado. Por último (mas não menos importante), agradeço aos meus irmãos Marise, Marta e Mauro por todo o apoio e ajuda que me deram ao longo de todos esses anos; sem esse apoio, a geologia seria para mim só uma velha história.

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The Fazenda Largo off-craton kimberlites of Piauí State, Brazil

Cited by 9 publications

References 13 publications

Constraining South Atlantic growth with seafloor spreading data

Constraining South Atlantic growth with seafloor spreading data

Thermobarometry of Diamond Inclusions: Evidence Mantle Evolution beneath Siberian Craton and Archean Cratons Worldwide.

Tectônica intraplaca e deformação sinsedimentar induzida por abalos sísmicos: o Lineamento Transbrasiliano e estruturas relacionadas na Província Parnaíba, Brasil

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