Tectonic and stratigraphic evolution of the Punta del Este and Pelotas basins (offshore Uruguay)

Morales, Ethel; Chang, Hung Kiang; Soto, Matías; Corrêa, Fernando Santos; Veroslavsky, Gerardo; Ana, Héctor de Santa; Conti, Bruno Martarello De; Daners, Gloria

doi:10.1144/petgeo2016-059

Cited by 32 publications

(32 citation statements)

References 24 publications

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“…Four main sedimentary megasequences are identified offshore Uruguay: (a) a Paleozoic pre‐rift sequence, (b) a Jurassic‐Early Cretaceous syn‐rift sequence, (c) a Barremian‐Aptian transition sequence and (d) a Aptian‐Holocene post‐rift sequence (Morales et al, ). This study focuses on the up to 3 km thick, Neogene to Holocene post‐rift sequence.…”

Section: Geological Settingmentioning

confidence: 99%

“…(a) Dip seismic section, (b) geosection, through the central Uruguay margin spanning the continental to transitional crust with significant volcanic components including SDRs, a high density underplating zone and intrusives. Stratigraphic ages are estimated from (Morales et al, ) and ANCAP. Note the study area, located down‐dip from a large prograding clinoform system…”

Section: Geological Settingmentioning

confidence: 99%

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Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

et al. 2019

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Strain style, magnitude and distribution within mass‐transport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and well‐imaged MTC, offshore Uruguay using a high‐resolution (12.5 m vertical and 15 × 12.5 m horizontal resolution) three‐dimensional seismic‐reflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismic‐attribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of sub‐orthogonal shear zones, and fold‐thrust systems within the basal shear zone beneath rafted‐blocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intra‐MTC rafted‐blocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain difference between extension (1.6–1.9 km) and contraction (6.7–7.3 km) is calculated. We attribute this to a combination of distributed, sub‐seismic, ‘cryptic’ strain, likely related to de‐watering, grain‐scale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits.

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Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

et al. 2019

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“…The horizons which bound the base and top of the Paleocene sequence are those named H.8 and H.9 by Morales et al (2017a). According to Conti et al (2017) and Creaser et al (2017), the ages of these horizons are top Cretaceous and top Paleocene, respectively (Fig.…”

Section: Methodsmentioning

confidence: 99%

Paleocene Seismic Facies in the Continental Margin of Uruguay (South America)

et al. 2019

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In this contribution seismic facies of the Paleocene sequence are characterized in offshore basins of Uruguay through the study of a 2D seismic database. Seven seismic horizons were identified, limiting six sedimentary intervals with different characteristics. Hence, the complexity of the Paleocene sequence is greater than suggested by other studies. Seismic facies located in the basis of the sequence can be interpreted as sandy deposits related to the action of both turbidity and bottom currents. The identification of these deposits agrees with the expected Cretaceous source rocks, in addition to the importance of the overlying Paleocene shales as a regional seal. The results of this work open interesting exploratory perspectives in the continental margin of Uruguay. FACIES SÍSMICAS DO PALEOCENE NA MARGEM CONTINENTAL DO URUGUAI (AMÉRICA DO SUL) ResumoNesta contribuição, as fácies sísmicas da sequência do Paleoceno são caracterizadas em bacias offshore do Uruguai através do estudo de uma base de dados sísmica 2D. Foram identificados sete horizontes sísmicos, limitando seis intervalos sedimentares com diferentes características. Neste estudo verifica-se que a complexidade da seqüência do Paleoceno é maior do que a sugerida por outros estudos. A fácies sísmicas localizadas na base da sequência podem ser interpretadas como sendo depósitos arenosos resultantes da ação de correntes de turbidez e de fundo. Estes depósitos correspondem a rochas-fonte cretáceas, estando cobertas regionalmente por importantes rochas selantes correspondentes a folhelhos do Paleoceno. Os resultados deste trabalho abrem interessantes perspectivas exploratórias na margem continental do Uruguai.Palavras-chave: Paleoceno. Facies Sísmicas. Margem Continental do Uruguai.

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“…For each well, its stratigraphy was defined on the basis of the stratigraphic analysis developed by Morales et al (2017). For each depositional sequence, the relative abundance of lithologies was estimated (Tabs.…”

Section: Methodsmentioning

confidence: 99%

Speculative petroleum systems of the Punta del Este Basin (offshore Uruguay)

et al. 2017

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The Uruguayan continental margin was generated as the result of the breakup of Gondwana and, later, the opening of the South Atlantic Ocean, which began in the Jurassic. Three major areas of Meso-Cenozoic sedimentation are located in the Uruguayan offshore: the Punta del Este Basin, the southernmost sector of the Pelotas Basin and the Oriental del Plata Basin. These basins share the classical stages of tectono-sedimentary evolution of the other Atlantic basins, including the prerift (Paleozoic), rift (Jurassic-Early Cretaceous), transition (Barremian-Aptian) and postrift (Aptian-present) phases. Based on the analysis of basin evolution through seismic sections and well data as well as on the establishment of analogies with productive Atlantic basins, four speculative petroleum systems are proposed for the Punta del Este Basin: 1) Marine petroleum system of the prerift stage: Devonian/Permian-Devonian/Permian(?), 2) Lacustrine petroleum system of the synrift stage: Neocomian-Neocomian(?), 3) Marine petroleum system of the Cretaceous postrift: Aptian-Late Cretaceous(?), 4) Marine petroleum system of the Cenozoic postrift: Paleocene-Paleogene/Neogene(?).

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Tectonic and stratigraphic evolution of the Punta del Este and Pelotas basins (offshore Uruguay)

Cited by 32 publications

References 24 publications

Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

Paleocene Seismic Facies in the Continental Margin of Uruguay (South America)

Speculative petroleum systems of the Punta del Este Basin (offshore Uruguay)

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