scholarly journals PALEOCENE SEISMIC FACIES IN THE CONTINENTAL MARGIN OF URUGUAY (SOUTH AMERICA)

2019 ◽  
Vol 4 (3) ◽  
pp. 263-275 ◽  
Author(s):  
Matías Soto ◽  
Belén Viera ◽  
Ethel Morales ◽  
Bruno Conti ◽  
Francisco Javier Hernández-Molina
Keyword(s):  
South America ◽  
Continental Margin ◽  
Source Rocks ◽  
Seismic Facies ◽  
Bottom Currents ◽  
Different Characteristics

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.

Anorogenic magmatism and the Grenvillian Orogeny

1989 ◽  
Vol 26 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Brian F. Windley
Keyword(s):  
United States ◽  
South America ◽  
Continental Margin ◽  
South Atlantic ◽  
Island Arc ◽  
The South ◽  
The West ◽  
Continental Block ◽  
Grenvillian Orogeny ◽  
Alkaline Complexes

The Grenvillian Orogeny was preceded by extensive anorogenic volcanism and plutonism in the period 1500–1300 Ma in the form of rhyolites, epizonal granites, anorthosites, gabbros, alkaline complexes, and basic dykes. An analogue for the mid-Proterozoic anorogenic complexes is provided by the 2000 km by 200 km belt of anorogenic complexes in the Hoggar, Niger, and Nigeria, which contain anorthosites, gabbros, and peralkaline granites and were generated in a Cambrian to Jurassic rift that farther south led to the formation of the South Atlantic. An analogue for the 1 × 106 km2 area of 1500–1350 Ma rhyolites (and associated epizonal granites) that underlie the mid-continental United States is provided by the 1.7 × 106 km2 area of Jurassic Tobifera rhyolites in Argentina, which were extruded on the stretched continental margin of South America immediately preceding the opening of the South Atlantic. The mid-Proterozoic complexes were intruded close to the continental margin of the Grenvillian ocean and were commonly superimposed by the craton-directed thrusts that characterized the final stages of the Grenvillian Orogeny. The bulk of the Keweenawan rift and associated anorogenic magmatism formed about 1100 Ma at the same time as the Ottawan Orogeny in Ontario, which probably resulted from the collision of the island arc of the Central Metasedimentary Belt attached to the continental block in the east with the continental block to the west. The most appropriate modern equivalent would be the Rhine Graben, which formed at the same time as the main Alpine compression.

SEISMIC FACIES OF SHELFEDGE DEPOSITS, U.S. PACIFIC CONTINENTAL MARGIN

1983 ◽  
pp. 299-313 ◽  
Author(s):  
MICHAEL E. FIELD ◽  
PAUL R. CARLSON ◽  
ROBERT K. HALL
Keyword(s):  
Continental Margin ◽  
Seismic Facies

Dynamics and evolution of continental margin clinoform systems

2020 ◽  
Author(s):  
Gerben de Jager ◽  
Dicky Harishidayat ◽  
Benjamin Emmel ◽  
Ståle Emil Johansen
Keyword(s):  
Sea Level ◽  
Continental Margin ◽  
Water Depth ◽  
Large Scale ◽  
Barents Sea ◽  
Source Rocks ◽  
Sea Level Changes ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Geological Processes

<p>Clinoforms are aquatic sedimentary features commonly associated with strata prograding from a shallower water depth into a deeper water depth. They are very sensitive to changes in water depth, rapidly moving along the shelf in response to sea level changes.  By reconstructing the initial clinoform geometry of buried clinoforms, an estimate of the paleo water depth (PWD) can be made. When this is done for several subsequent clinoform sets the amounts and rates of bathymetric changes can be calculated.</p><p>Here we present a novel approach to estimate clinoform parameters and depositional depths for continental margin clinoforms using seismic reflections, wellbore and biostratigraphy data. Seismic interpretation of three relatively east-west regional full-stack seismic reflection data from the continental margin of the western Barents Sea revealed twelve Late Cenozoic horizons. The clinoform shapes have been restored by removing the effects of compaction and flexural isostasy (backstripping). This includes the effects of glacial/interglacial scenarios on horizons with strong glaciomarine seismic indications.</p><p>Based on the reconstructed clinoform geometries we use empirical relationships from literature between clinoform geometry and depositional depth to estimate PWD values. In these analyses it is possible to estimate the PWD of the upper rollover point and the toe point by measuring the bottomset height, foreset height and topset height. A sensitivity analysis study has also been done on several different scenarios, varying elastic thickness, decompaction and net to gross ratio. Comparison with biostratigraphic water depth estimates indicate that PWD estimates revealed from clinoform parameters give reliable results.</p><p>Any mismatch between the backstripped PWD values and the PWD values derived from the clinoform geometry can then be attributed to geological processes not included in the backstripping process. Among others, these could be explained by rifting, thermal effects in the lithosphere, faulting or eustatic sea level changes. This allows the quantification of the magnitude of these large-scale crustal processes through time.</p><p>We will demonstrate that this method can further constrain the PWD on the continental margin clinoform system and thus can help to improve the understanding of the interplay between sedimentary processes and large-scale crustal processes. Furthermore, the PWD estimates will be a reliable input for further analysis of source-to-sink and stratigraphic forward modeling studies as well as reservoir and source rocks prediction on the petroleum development and exploration.</p><p> </p>

scholarly journals Palaeoenvironment and Its Control on the Formation of Miocene Marine Source Rocks in the Qiongdongnan Basin, Northern South China Sea

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Wenhao Li ◽  
Zhihuan Zhang ◽  
Weiming Wang ◽  
Shuangfang Lu ◽  
Youchuan Li ◽  
...  
Keyword(s):  
South China Sea ◽  
Continental Margin ◽  
South China ◽  
Northern South China Sea ◽  
Qiongdongnan Basin ◽  
Source Rocks ◽  
Hydrocarbon Potential ◽  
China Sea ◽  
Marine Source ◽  
Main Factors

The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter.

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