Provenance and paleogeographic reconstruction of a mesoproterozoic intracratonic sag basin (Upper Espinhaço Basin, Brazil)
Date
2015
Authors
Santos, M. N
Chemale, F
Dussin, I. A
Martins, M. S
Queiroga, G
Pinto, R. T. R
Santos, A. N
Armstrong, Richard
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The Mesoproterozoic Conselheiro Mata Group is the uppermost sequence of the Proterozoic intracontinental
Espinhaço basin that developed on the Congo-São Francisco Paleoplate. This sequence is represented by a marine
shallow-water platform that experienced a sag phase followed by a rift phase in the Upper Espinhaço. We used
combined sedimentological-stratigraphic descriptions of sections, whole-rock (WR) geochemistry and U-Pb
detrital zircon dating to develop a regional paleogeographic evolution model of the sag phase. The succession
corresponds to transgressive-regressive cycles in the following ascending order: 1) offshore to lower shoreface
facies represented by quiescent periods and episodic sediment supply (Santa Rita Formation); 2) upper shoreface
to foreshore and coastal desert facies with a reworking of the underlying units (Córrego dos Borges Formation);
3) lower shoreface with fallout of suspended fine sediments and a combination of unidirectional and oscillatory
flows generated by storm waves (Córrego da Bandeira Formation); 4) tidal-influenced upper shoreface to
foreshore facies with the migration of subaqueous dunes, wave swash in a beach environment and cycles of
neap-spring tides (Córrego Pereira Formation); and 5) the resumption of lower-shoreface sedimentation and
the subsequent development of a stromatolitic carbonate-siliciclastic platform (Rio Pardo Grande Formation).
The geochemical data indicate that the studied units contain input from felsic rocks and sedimentary rocks.
The basal marine to eolian sediments of the Galho do Miguel Formation are dominated by Rhyacian sources
(2.1 Ga). The basal and intermediate units of the Conselheiro Group contain Archean, Rhyacian, Statherian and
Calymmian-Ectasian (1.6–1.33 Ga) zircon grains, whereas Orosirian (1.9–2.0 Ga) sources dominate in the
upper strata of the group. The study of this Stenian (Mesoproterozoic) intracratonic sequence provides clues
to understanding the history of sedimentation and the potential source areas on the São Francisco Craton and
adjacent areas, which are very useful for comparison to Phanerozoic intracratonic basins and the reconstruction
of Paleoproterozoic and Mesoproterozoic supercontinents.
Description
Keywords
Stenian, Espinhaço basin, U-Pb zircon geochronology, São Francisco craton
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Source
Sedimentary Geology
Type
Journal article