227 D22. Recent Advances in Precambrian Geology (Posters)

Wednesday, 13 October 2021
9:00 AM - 1:00 PM
Exhibit Hall A

MULTI-DIMENSIONAL SCALING OF DETRITAL ZIRCON GEOCHRONOLOGY CONSTRAINS BASIN EVOLUTION OF THE LATE MESOPROTEROZOIC PARANOÁ GROUP, CENTRAL BRAZIL

Paper number: 227-7
Program: Technical Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

Proterozoic basin data are commonly difficult to access due to the complexity of tectonic processes and lack of volcanic rocks and fossil record. The Mesoproterozoic Paranoá Basin, in Central Brazil, was investigated through stratigraphic framework integration, depositional environmental analysis and with detrital zircon and statistical data. Paranoá Group was evolved in three phases: i) Proto-Basin Stage represents the basal succession, including the transition from the continental environment (alluvial fans) to shallow water platform conditions; ii) Expansion Basin Stage, which includes the most significant sediment thickness and the essential contrasting depositional environment, including tide-dominated platform, storm dominated platform, supratidal and foreshore conditions and iii) Final Basin Stage represents the shallower environment condition, including mixture siliciclastic - carbonate succession. The stages are related to different depositional space creation mechanisms: mechanical subsidence to the Proto-Basin Stage, thermo-flexural subsidence to the Expansion Basin Stage, and flexural subsidence to the Final Basin Stage. The detrital zircon data allied with MDS (multidimensional scale) were crucial to constrain the basin's tectonic evolution. For the basal succession, the maximum depositional age is ~1.5 Ga with the local crystalline basement (Aurumina Suite tonalitic and granodioritic gneiss). The source areas changed during the expansion stage, in which the sedimentary successions accumulated during this stage present maximum depositional age of ~1.3 Ga and a widespread distribution pattern. In the final phase, the maximum depositional age is ~1.1 Ga, including a complex distribution of ages representative of different source areas.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-369781

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