Age constraints on crystal-tuff from the Espinhaco Supergroup - Insight into the Paleoproterozoic to Mesoproterozoic intracratonic basin cycles of the Congo-Sao Francisco Craton

作者：Guadagnin Felipe^*; Chemale Farid Jr; Magalhaes Antonio J C; Santana Ana; Dussin Ivo; Takehara Lucy

来源：Gondwana Research, 2015, 27(1): 363-376.

DOI：10.1016/j.gr.2013.10.009

• Espinhaco Supergroup
• Congo-Sao Francisco Craton
• U-Pb and Lu-Hf zircon dating
• Precambrian intracratonic sequences

The U-Pb data from the volcanic and detrital zircon grains of the Tombador Formation in Chapada Diamantina, Bahia, provide the depositional age of the top of this unit and define the main sedimentary sources of the Archean, Paleoproterozoic and Mesoproterozoic Eras. The lithofacies, petrographic and geochemical data from crystal-tuff samples indicated that a volcanic source was located to the east of the Chapada Diamantina region. The available zircon data defined three first-order intracratonic basinal cycles, including the Lower (Statherian), Middle (Calymmian) and Upper (Stenian-early Tonian) Espinhaco basins. These sequences are well exposed at the Espinhaco Supergroup type-section in the Chapada Diamantina region. The zircon Hf isotope data from the 1.4 Ga crystal-tuff in the Middle Espinhaco and the 12 Ga tuffaceous rock in the Upper Espinhaco suggested different sources, with model ages of 2.1 to 1.9 Ga and <1.9 Ga, respectively. The tectonic development of these Paleoproterozoic to Mesoproterozoic intracratonic basins can be explained by the far-field stress at the paleoplate margins, which has been shown in other Phanerozoic intracratonic basins. The data presented here support a tectonic scenario in which the Congo-Sao Francisco paleoplate interior recorded the main global events related to the geodynamic processes after the Columbia supercontinent collage and the formation and fragmentation of the Rodinia supercontinent.

• 出版日期2015-1