--> --> Paleoenvironmental, Paleoecological and Tectonic Considerations from Onshore Mucuri Member, Neo-Aptian, Espirito Santo Basin, Brazil, Tokutake, Lucio R.; Stirling, Robert A.; Zambonato, Eveline E.; Anaisse, Jose; Souza, Paulo A.; Dutra, Tania L., #90100 (2009)
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Previous HitPaleoenvironmentalNext Hit, Paleoecological and Tectonic Considerations from Onshore Mucuri Member, Neo-Aptian, Espirito Santo Basin, Brazil

Tokutake, Lucio R.1
 Stirling, Robert A.1
 Zambonato, Eveline E.1
 Anaisse, Jose2
 Souza, Paulo A.3
 Dutra, Tania L.4

1UN-ES/EXP/SE, PETROBRAS, Vitoria, Brazil.
2
UN-ES/EXP/ABIG, PETROBRAS,
Vitoria, Brazil.
3
IG/DPE, UFRGS,
Porto Alegre, Brazil.
4
UNISINOS,
São Leopoldo, Brazil.

The neo-Aptian Mucuri Member of Mariricu Formation, in
Espirito Santo Basin, SE Brazilian continental margin is an exploratory target since 1960’s. Many studies on sedimentology, petrology, biostratigraphy were carried out along these years. As the studied area was in a non-marine section, only palinology was carried out, but just for biostratigraphic purposes.
The main well was in a very proximal area in neo-Aptian morphology, with continuous cored section that made possible to carry out many accurate Previous HitanalysisNext Hit.

Sandstones are predominant in Mucuri member along these cores, which are divided into two depositional sequences: one basal with fluvial facies and another characterized by alluvial facies.
Petrographical Previous HitanalysisNext Hit shows very immature facies (textural and mineralogical) in both sections, with grains just a little better sorted in the fluvial section.

Structural aspects make the main well remarkably different from the others. Placed in the very border of the basin, with a relative high basement plateau showing a hinge line to the east. This hinge line is locally parallel to the Cedro Paleocanyon border and shows fractures such as positive flower and pinnacles due to meso-eocenic reactivation.

The palynological assemblages are marked by continental elements, with a considerable amount of opaque and non-opaque phytoclasts and rare cuticles. Pollen grains of Classopolis (Cheiropidiaceae) constitute the predominant group, commonly recorded in form of tetrads, as well as Gnetales. Pollen grains of Araucariacites australis are less abundant, but important.
The good preservation and the high frequency of tetrads (mainly Classopolis classoides) indicate a very short transport and a very short fossil exposition.

The predominance Cheirolepideaceae and Gnetales suggests a hot and dry paleoclimate. Beside Araucariacites australis suggests highlands very close to depositional site.
The other wells are in a less proximal area, without cores. The palinological content shows Classopolis classoides predominance too, but tetrads are less common, with Gnetales, spores and rare but constant Aruacariacites australis.
Integration of the available data allows an interpretation of a depositional site in low area with non perennial rivers, under hot and arid climate, receiving alluvial fan influx from a rise beside. The integration of different data sets and knowledge allowed a more accurate interpretation of the Previous HitpaleoenvironmentalTop context.

AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil