Abstract
We studied Holocene paleoenvironmental changes in the Soya Kaigan of East Antarctica inferred from the analyses of Lake Oyako-ike sediment core (Ok4C-01, length 135 cm) , along with sedimentary facies and AMS 14C dating. The Ok4C-01 core was composed of clayish mud containing laminae between 135-65.5 cm. This was overlain by organic sediments containing algal mats between 65.5-0 cm. The mean sedimentation rate and uplifting rate were estimated to be 0.69 mm/y and 2.2 mm/y, respectively. The low biological production with diatom in coastal marine environments (135-74.75 cm, ca.2,170-1,300 cal BP), changes into green sulfur bacteria in stratified saline lake in 74.75-60.95 cm (ca.1,300-1,100 cal a BP), and then high biological production with cyanobacteria and green algae in lacustrine environments (60.95-0 cm, ca.1,100-220 cal BP). The ongoing retreat of glaciers and ongoing isostatic uplift during the mid-Holocene Hypsithermal (4.5-2.8 cal ka BP) and thereafter are the main reasons for this isolation, whereas eustatic sea level change is believed to have played only a minor role.
