Grain size and heavy mineral distribution as related to hinterland and environmental conditions for modern beach sediments from the Gulfs of Antalya and Finike, eastern Mediterranean Mustafa Ergin a,b, ⁎ , Şeref Keskin c , A. Umran Doğan b , Yusuf Kaan Kadıoğlu b , Zehra Karakaş a,b a Ankara University, F.L. Marine Geological Research Center (AGDEJAM), Tandogan, Ankara, 06100, Turkey b Ankara University, Faculty of Engineering, Department of Geological Engineering, Tandogan, Ankara, 06100 Turkey c Niğde University, Faculty of Engineering, Department of Geological Engineering, Niğde, 51100 Turkey Received 24 October 2005; received in revised form 5 February 2007; accepted 16 February 2007 Abstract Backshore sediment samples from 22 beaches along the Antalya and Finike Gulfs have been studied for their grain size, chemical and heavy mineral composition. Data presented here suggest that well- to moderately-sorted (0.41 Φ–0.92 Φ) medium sand (1 Φ–2 Φ) represents dominant mean grain size in most beaches. In contrast, some beaches from the western part of the Gulf of Antalya (Göynük, Kemer-Kiriş and Beldibi) are composed of pebble- to boulder-size grained beaches which are located close to mouths of short and steep-gradient ephemeral rivers entering the sea from the Western Taurus Mountains. The heavy mineral assemblages are dominated by detrital opaque minerals (14–58% magnetite, chromite, and hematite), pyroxene (8–65% augite), amphibole (3–15% tremolite and actinolite), epidote (3–25%), garnet (2–9% pyrope and almandine) and micas (3–20 biotite, muscovite and chlorite). The very high concentrations of heavy minerals (up to 86% of bulk sediment) together with the significant concentrations of some elements found in beach sediments from the Gulf of Finike and western Gulf of Antalya (Fe: 18.40%; Cr: 10.00%; and Ti: 1.32%) are indicative of ultramafic origin, mainly derived from the ophiolitic rocks of the Antalya–Tekirova nappe on coastal hinterland. © 2007 Elsevier B.V. All rights reserved. Keywords: grain size; heavy minerals; beach; sediment; geochemistry; Gulf of Antalya; Gulf of Finike; southern Turkey; eastern Mediterranean 1. Introduction Recent studies have shown (e.g., Dill, 1998) that distribution of heavy minerals in marine beach sediments is primarily a function of the interaction between the extrabasinal such as source area weathering and in- trabasinal processes (e.g., hydraulic processes). For example, Rigler and Collins (1984),Anfuso et al. (1999), Hoffman et al. (1999),Frihy and Dewidar (2003) suggested that heavy mineral assemblages supply valuable information to understand erosional, grain motion, littoral dynamic, and longshore drift processes in coastal zone. Other studies have attempted to dis- tinguish heavy mineral provinces and related source rocks in a given region (Mange-Rajetzky, 1983; Grigsby, Marine Geology 240 (2007) 185 – 196 www.elsevier.com/locate/margeo ⁎ Corresponding author. Ankara University, F.L. Marine Geological Research Center (AGDEJAM), Tandogan, Ankara, 06100, Turkey. Tel.: +90 312 215 0487. E-mail address: ergin@eng.ankara.edu.tr (M. Ergin). 0025-3227/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.margeo.2007.02.006