DATE2016-05-30 14:27:16
IDABSTRACT20160530142716-1017
CONTACTbora.on@gmail.com
PRESENTATIONPOSTER
INVITED0
IDSESSION3
TITLEEXTRACTING THE PRECIPITATION AND TEMPERATURE PROXIES FROM LAKE HAZAR (SE ANATOLIA) M-XRF CORE DATA, BY USING INDEPENDENT COMPONENT ANALYSIS
AUTHORSZ Bora Ön (1,2), Sena Akçer-Ön (1), M Sinan Özeren (2), K Kadir Eris(3), Alan M Greaves (4), M Namik Cagatay (3)
AFFILIATIONS
  1. Mugla Sk Ãœniversitesi, Jeoloji Mugla (Turkey)
  2. ItÜ, Avrasya Yer Bilimleri Enstitüsü Istanbul (Turkey)
  3. ItÜ, Emcol Istanbul (Turkey)
  4. University Of Liverpool, Archaeology Liverpool (United Kingdom)
ABSTRACTPast climate proxies are typically nonlinear combinations of statistically independent or quasi-independent processes, and are thus indirect indicators. In this study, we propose the method of Independent Component Analysis (ICA) as a tool to extract statistically independent climate signals from m-XRF core data. ICA's advantage over traditional dimension reduction methods is that, rather than uncorrelatedness, it aims to achieve maximal independence which is a stronger statistical statement. In 2011, a 3.5 m long Hz11-P03 core was recovered at a water depth of 54 m from Lake Hazar,SE Anatolia. According to our age model, it spans the last 17.8 ka. A hiatus at 270 cm reveals that the lake level must have dropped by at least 54 m below its current level between 12.46 ka and 11.76 ka BP, which effectively masks any data for the Younger Dryas stadial. Applying the ICA method, we selected two out of six independent components using the distance correlation similarity measure. We propose that one of the selected components can be read as a proxy for temperature and the other for precipitation in this region. Our results indicate that the region was cold and humid between 17.8 ka and 14.8 ka BP but wet and warm during the Bølling-Allerød. . At the start of the Holocene, while precipitation values were high, the temperature gradually increased until 9 ka BP. Between 8 ka and 5 ka BP, the region was warm but extremely dry. Around 3.5 ka BP, temperatures dropped suddenly and three abrupt dry phases are observed at around 3.5 ka, 2.8 ka and 1.8 ka BP. The project is supported by the Scientific and Technological Research Council of Turkey (TUBITAK) project no. (111Y045).
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