Özet:

This paper discusses formation environment of beachrock exposed on Kumlimani Beach west coast of Gelibolu Peninsula, Turkey, based on field observations, petrographic thin section and scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDX) analyses. The studied beachrock is a poorly-sorted coastal conglomerate composed of radiolarite and limestone gravels. Quartz and carbonate grains form the predominant components. Based on EDX analysis results, the composition of beachrock cement is dominated by various elements, ranging in decreasing order of O>C>Ca>Si>Cl>Na>Mg>S>Al>Fe and K. We identified different types of cements of intertidal origin, dominated by micrite envelops, bladed isopachous high magnesium calcite rims, and, less importantly, meniscus bridges. High-magnesium calcite is preponderant within intertidal cements in proportion to those in meniscus bridges, containing low magnesium calcite. The results suggest the characteristics of early phases of carbonate cementation in the studied beach. Keywords: Beachrock, cementation, intertidal zone, supratidal zone, Gelibolu Peninsula, Turkey.

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