Influences of Climate and Tectonic on the Middle to Late Holocene Deltaic Sedimentation in Lake Hazar, Eastern Turkey

Analyses of two piston cores from Lake Hazar together with high-resolution seismic data provide unique evidence of complex interaction of tectonics and lake level changes during the mid-to-late Holocene. This period is associated with stacked shelf-edge deltaic units at the mouth of the Kurk double dagger ayA +/- River at the western extreme of the lake. Despite the general dry climate during the middle Holocene (between 8.2 and 5.1 cal ka BP), transgressive and landward retreating deltaic successions developed due to the deepening of the lake that induced by transtentional activity of the East Anatolian Fault Zone. The arid climate during 5.1-2.6 cal ka BP is supported by the multi-proxy analyses of the cores. This period coincides with the late Bronze age deforestation, which probably provided the sediment supply by soil erosion for the deltaic deposition at the mouth of the paleo-Kurk double dagger ayA +/- River. On the other hand, the flooding of the youngest deltaic unit in the lake took place under a general wet climate after 1.4 cal ka BP. The seismic architecture and the core sedimentology indicate that the existing hydrological regime with the latest deltaic deposition started 2.6 cal ka BP was accompanied by a hyperpycnal mixing

Authigenic carbonate mineral formation in the Pagassitikos palaeolake during the latest Pleistocene, central Greece

The Pagassitikos Gulf in Greece is a semi-enclosed bay with a maximum depth of 102 m. According to the present-day bathymetric configuration and the sea level during the latest Pleistocene, the gulf would have been isolated from the open sea, forming a palaeolake since ~32 cal. ka b.p. Sediment core B-4 was recovered from the deepest sector of the gulf and revealed evidence of a totally different depositional environment in the lowest part of the core: this contained light grey-coloured sediments, contrasting strongly with overlying olive grey muds. Multi-proxy analyses showed the predominance of carbonate minerals (aragonite, dolomite and calcite) and gypsum in the lowest part of the core. Carbonate mineral deposition can be attributed to autochthonous precipitation that took place in a saline palaeolake with high evaporation rates during the last glacial–early deglacial period; the lowest core sample to be AMS 14C dated provided an age of 19.53 cal. ka b.p. The palaeolake was presumably reconnected to the open sea at ~13.2 cal. ka b.p. during the last sea-level rise, marking the commencement of marine sedimentation characterised by the predominance of terrigenous aluminosilicates and fairly constant depositional conditions lasting up to the present day