The Serra Grande Group represents the first transgressive - regressive megacycle deposited in the Parnaíba Basin during the silurian, Gondwana supercontinent's western region. Ipu Formation (sandstones and conglomerates), Tianguá Formation (shale, siltstone and sandstones) and Jaicós Formation (siltstone and sandstone) are inserted in Serra Grande Group and they consist in a succession of until 125 m, which are exposed in excellent sections in Ibiapaba's Serra, Ipueiras region, State of Ceará. Previous stratigraphic and facies association studies of this succession indicates that Ipu Formation represents braided fluvial system influenced by glacial processes on top. The abrasion of the crystalline basement rocks generated sediments rich in lithic fragments and rich in sandy- clay matrix. The post - glacial period was marked by deposition of transgressive marine siltstones of Tianguá Formation initially influenced by clasts influx and sand coming from icebergs. Later, there was the progradation of fluvial-deltaic system of Jaicós Formation characterized by sands rich in quartz. Petrographically the Ipu’s Formation sandstones consist, predominantly in quartz arenites, subarkoses and litharenites while quartz arenites characterize Jaicós Formation. In stages eo- and mesodiagenetic occurred deformation of grains, the primary porosity (?) of sandstones was obliterated by authigenic constituents that also occurs in the form of cement (carbonate and quartz), which also filled fractures. The textural and compositional aspects of sandstones of Serra Grande Group suggest different source areas for this succession. Lithic sands of Ipu Formation were replaced by predominantly quartz sands of Jaicós Formation indicating the end of glacial erosion on the basement rocks related to the Borborema Province, the eastern portion of the Parnaíba Basin. The textural and compositional indications obtained in this work about the Serra Grande Group assist futures sedimentological studies focusing on provenance and contribute to sediment west Gondwana evolution during the Silurian.
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