Nova unidade litoestratigráfica registra glaciação ediacarana em Mato Grosso: formação Serra Azul

Chapter 46 The Serra Azul Formation, Paraguay Belt, Brazil

“…This unit comprises a reddish laminated siltstone that in places contains sparse granules (2 -3 mm) of quartzite and quartz (Figueiredo et al 2008). Towards the top, this reddish siltstone grades into rhythmites that are about 150 m thick (Figueiredo et al 2008). At the base of this succession, there are alternating clayey and silty plane-parallel laminae with intercalations of sandstone layers (5 -10 cm thick) showing small hummocky lamination that indicates oscillatory flow events.…”

“…The clast size ranges from granules, pebbles (c. 5%) and cobbles (c. 1%) to boulders (1%), with a few reaching 30 cm in diameter (Figueiredo et al 2008). Their shape also varies from well rounded to highly angular; some are faceted, polished and striated.…”

“…This unit comprises a reddish laminated siltstone that in places contains sparse granules (2 -3 mm) of quartzite and quartz (Figueiredo et al 2008). Towards the top, this reddish siltstone grades into rhythmites that are about 150 m thick (Figueiredo et al 2008).…”

“…The contact with the Serra Azul Fm. is gradational in the Azul Range region and erosive in other localities (Figueiredo et al 2008), where the Nobres Fm. is in sharp contact with the Raizama Fm.…”

Sedimentação autigênica neoproterozóica e mineralizações associadas: um registro não uniformitarista

“…). Na região de Serra Azul, foi observado corpo restrito de diamictios, posicionado acima do Grupo Araras, com blocos e seixos de dolomito silicificado do Grupo Araras e blocos de quartizito estriados, interpretados como glaciais e relacionados à glaciação Ediacarana -Gaskier (Almeida 1964b, Alvarenga et al 2007, Figueiredo et al 2008 …”