Surface microtextures of quartz grains and minor sedimentary components across the Paleolithic Jeongok-ri sediments, Yeoncheon, South Korea

초록

The Jeongok-ri Paleolithic site in the central Korean peninsula is known as the first findspot of Acheulean-type hand axes in East Asia. Although many previous studies have investigated the depositional environments of Jeongok-ri sediments across the Paleolithic occupation, they remain controversial. In this study, we collected an 11-m-long core to obtain evidence from systematic surface microtextures of quartz grains (SMQs) concerning depositional environments in the Jeongok-ri archeological site. SMQs in the Jeongok-ri sediments are characterized by dominant angular to subangular outlines and small to large conchoidal fractures with arcuate steps, as well as sparse V-shaped percussion cracks; these features suggest short distances and subaqueous transportation with grain-to-grain collisions and violent impacts of quartz grains. On the basis of simultaneous sedimentation of the hosting silt deposits, our SMQ results suggest that Jeongok-ri sediments were originally fluvial, regardless of their intermediate sedimentary history. This evidence from quartz grain microtextures is consistent with minor sedimentary components found in the Jeongok-ri core sediments, such as diatom grains as microfossil constituents, along with macroscopic charcoals and titanium-bearing detrital magnetite grains. The geological and geomorphological conditions of the Jeongok-ri site are also favorable for floodplain environments given the position adjacent to river terraces formed by the previous lateral erosion of a meandering channel in the nearby Hantan River. Our findings will help to understand environmental conditions during the development of Paleolithic cultures in East Asia. (c) 2023 John Wiley & Sons, Ltd.

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