High-frequency/low amplitude eustatic parasequences in Neoproterozoic Alto Paraguai basin (Mato Grosso, Brazil)

Abstract

The tectono-sedimentary evolution of the Itararé Subgroup (Late Paleozoic) in the southern flank of the Ponta Grossa arch, States of Santa Catarina and Paraná, Brazil, is interpreted through stratigraphic analysis of outcropping beds. Its evolution seems to have been influenced by faulting causing rising and falling of the arch. The section analyzed runs some 50 km SE-NW, from Mafra (SC)-Rio Negro (PR) to Lapa (PR) and includes about 700 m thickness of glacio-clastic beds assigned to the Campo do Tenente and Mafra formations.

Low‐latitude and multiple geomagnetic reversals in the Neoproterozoic Puga cap carbonate, Amazon craton

“…The presence of aragonite‐pseudomorph crystal fans and crusts directly precipitated on the seafloor is striking evidence for the anomalously high temperatures at the end of the Neoproterozoic ice ages (Sumner, 2002). In the Puga cap carbonates these typical associations are replaced upsection by other strata with structures that also indicate warm conditions (Nogueira and Riccomini, 2001). Metre‐scale shallowing/brining‐up cycles of arid tidal flat and sabkha occur at the top of the sequence, presenting fenestral and birdseye laminations, desiccation cracks, rip‐up clasts, pseudomorphs of nodular gypsum and tepee structures (e.g.…”