Lithostratigraphy and planktonic foraminifera of the uppermost cretaceous-upper palaeocene strata of the tavas nappe of the Lycian nappes (SW Turkey)

Abstract

The Lycian nappes lying on top of the para-autochthonous metamorphosed Menderes and un-metamorphosed Bey Dağları successions in SW Anatolia belong to the Tauride segment of the Anatolide-Tauride Block. The Tavas nappe is one of several nappe slices of the Lycian nappes and forms structurally the lowermost tectono-stratigraphic unit. The upper part of the Tavas nappe succession is represented by planktonic foraminifera-bearing uppermost Cretaceous cherty micritic limestones and calciturbidites of the Babadağ Formation and Lower Palaeogene micritic limestones and calciclastic rocks of the Faralya Formation in the study area. Lithostrati-graphic characteristics and planktonic foraminiferal assemblages of the two formations in the Bozburun hill locality (S of Köyceğiz) are documented for the first time in three stratigraphic sec-tions in this study. The uppermost part of the Babadağ Formation mainly comprises of alternating calciclastic and micritic limestones, which include diverse planktonic foraminiferal assem-blages of mainly keeled morphotypes. The presence of Racemiguembelina fructicosa and Abathomphalus mayaroensis within the assemblages indicates a late Maastrichtian age for the uppermost part of the succession. Two sections of the overlying Faralya Formation comprise mainly planktonic foraminifera-bearing laminated micritic limestones, brecciated limestones and mudstones. Planktonic foraminiferal assemblages of the laminated micritic limestones are domi-nated by keeled Late Palaeocene morphotypes. The occurrence of Morozovella acuta and Globanomalina planoconica at the base of two sections suggests a Thanetian age for the deposits. The boundary between the Babadağ and Faralya formations is characterized by a stratigraphic gap ranging from the latest Maastrichtian to the earliest Selandian. The gap was linked with the first of the three main events, when ophiolite obduction and incorporation of the Köyceğiz Thrust Sheet into the Lycian allochthon occured. Cretaceous limestone clasts and foraminifers within the Thanetian calciclastic rocks of the Faralya Formation could be clues to that exposure and erosion.