Sedimentary characteristics of the Hüdaý Formation (Early Cambrian) within the Aydincik (ÝÇEL) area, S Turkey

The study area is located in Aydincik area where Early Cambrian rocks are represented by the Hiidai Formation. The formation represents three different parts in the vertical sequence which has a thickness of approximately 830 metres. The basal part of the formation consists of a rhytmic alternation of horizontal laminated sandstone, ripple trough cross-laminated sandstone, mixed sandstone-shale, and rarely metashales. The middle part comprises dominantly metashales. The upper part is made up by an alternation of horizontal laminated sandstone, mixed sandstone-shale and rarely metashales. Vertical variations in the formation is caused by marine transgressious and regressious, and by fluctuations in sediment supply. Lower to middle parts of the formation characterize a fining-upward sequence, and middle to upper parts display a coarsening-upward sequence. In the Hiidai Formation, four lithofacies are recognized based on lithology and sedimentary structures. These are (1) horizontal laminated sandstone (predominantly quartzarenite) indicating deposition from tidal currents during the high velocity phases of tidal cycles; (2) ripple cross-laminated sandstone (predominantly quartzwacke) deposited in lower part of intertidal (sand-flat) environment; (3) mixed sandstone-shale revealing deposition in mid-intertidal flat environment; and (4) shale (or metashale) deposited mainly in upper intertidal (mudflat) environment.