GEOLOGY, November 2011 1051 INTRODUCTION After millennia of generally cold but vari- able climate, the warming trend at the end of the Pleistocene epoch led to the establishment of a warm climate of the Holocene epoch (the past 11.6 k.y.). Ice-core data suggest that the Holocene was climatically stable (Dansgaard et al., 1993), but other paleoclimate proxy data (e.g., Bond et al., 1997; de Menocal et al., 2000) show clear variations. Understanding climatic changes during the Holocene provides long-term context for the assessment of the nature of the climate change today. The global temperature rise of the past century (Folland et al., 2001) could be considered unique within the Holocene under the assumption of a rela- tively stable climate of the Holocene (Dans- gaard et al., 1993), but unexceptional under the assumption of large climatic variations (de Menocal et al., 2000). In this paper we pres- ent new results that indicate an extensive late Pleistocene-early Holocene glaciation from south-central Turkey, from which we infer the magnitude and pace of glacial and climatic changes. Glaciers are not among the first things usu- ally associated with Turkey, but glaciers exist in Turkey today (Çiner, 2004; Sarıkaya et al., 2011), and, as noted first by Palgrave (1872), glacial geological evidence shows that much bigger glaciers existed in Turkey in the past, providing information on former climate changes (Erinç, 1952). Temperate mountain glaciers are sensitive to changes in climate (Oerlemans, 2001), mainly temperature and precipitation, because their temperature is close to the melting point of ice (Nesje, 2005; Ohmura et al., 1992). Variations in glacier size provide some of the clearest natural signals of climate change today (Nesje, 2005). By anal- ogy, dating of moraines provides information on past climates. GEOLOGIC SETTING We dated moraines in the Aladağlar (in Turkish, “ala” means speckled, “dağlar” means mountains) (37°8′N, 35°2′E) of the Central Taurus Mountains of Turkey. The highest part of the mountain range consists of Mesozoic carbonates with extensive karst that limits sur- face drainage (Tekeli et al., 1984; Klimchouk et al., 2006). The modern climate is a mixture of Mediterranean and continental type, with hot and dry summers and wet and cold win- ters. The Aladağlar bear conspicuous evidence of former glaciers (Klaer, 1962; Klimchouk et al., 2006; Tekeli et al., 1984). Former gla- ciers developed in cirques above 3000 m and flowed down deeply incised valleys. Numerous morphological features record former glacia- tions in the Yedigöller (Seven Lakes) Plateau, a large depression just below the summits of the Aladağlar, and in the Hacer (Rock) Val- ley, a deep, U-shaped glacial valley, the largest in the Aladağlar (14 km long), located on the east side of the mountains (Fig. 1). Features of glacial erosion, i.e., cirques, glacially scoured bedrock, striations, trim lines, aretes, and horns, are common in the Yedigöller area and in the upper valley, above 2000 m (Klimchouk et al., 2006). Features of glacial deposition (moraines, glacial lakes, and outwash deposits) are present at all elevations. In the Hacer Val- ley and in the Yedigöller Plateau, we mapped seven moraines at elevations from ~3100 m to ~1100 m (A-G in Fig. 1; Table DR1 in the Geology, November 2011; v. 39; no. 11; p. 1051–1054; doi:10.1130/G32097.1; 3 figures; Data Repository item 2011308. © 2011 Geological Society of America. For permission to copy, contact Copyright Permissions, GSA, or editing@geosociety.org. *E-mail: mehmetakifsarikaya@gmail.com. Remarkably extensive glaciation and fast deglaciation and climate change in Turkey near the Pleistocene-Holocene boundary Marek Zreda 1 , Attila Çiner 2 , Mehmet Akif Sarıkaya 1,3 *, Chris Zweck 1 , and Serdar Bayarı 2 1 Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721, USA 2 Department of Geological Engineering, Hacettepe University, 06800 Beytepe, Ankara, Turkey 3 Department of Geography, Fatih University, 34500 Büyükçekmece, Istanbul, Turkey ABSTRACT Moraines in the Taurus Mountains of south-central Turkey, dated to latest Pleistocene or earliest Holocene, show that glaciers were extraordinarily large, typical of the Last Glacial Maximum (21 ka), and that rates of glacier retreat and temperature rise exceeded those of the past century. Surface exposure ages of 7 moraines in a valley at altitudes between 1100 m and 3100 m above sea level range from 10.2 ± 0.2 ka to 8.6 ± 0.3 ka, computed using our own production rates and spatiotemporal scaling factors. Hitherto unresolved differences in cosmogenic 36 Cl production-rate estimates can make these ages significantly older, and therefore the analysis presented here focuses on the rate of change and not on the absolute chronology. During deglaciation, the equilibrium line altitude ascended 1430 m and the air temperature rose by 9 °C. Deglaciation occurred in two phases. During the second, faster phase, which lasted 500 yr, the glacier length decreased at an average rate of 1700 m/100 yr, implying a warming rate of 1.44 °C/100 yr, indicating a rapid climate shift marking the onset of the Holocene in Turkey. Figure 1. A: Location map of Aladag ˘lar. B: View of Hacer Valley (looking to northwest). C: Moraine and sample locations in Yedigöller Plateau and Hacer Valley. Separate moraines are labeled from A (highest elevation) to G (lowest). Central flow line is shown in 1-km-long segments. Asterisks indicate bedrock samples.