GLACIAL-INTERGLACIAL CYCLES AND HOMINID DEVELOPMENT IN NORTH CHINA DURING EARLY PLEISTOCENE

The hominid development in East Asia is key in understanding the hypothesis of dispersion of early human following the “Out of Africa” stage in the Early Pleistocene but has long been disputed. A crucial question is whether hominid can survive the harsh climate during glacial periods at high latitudes (e.g., 40°N). To resolve the question, we reconstruct the paleoclimatic histories in the Nihewan Basin of North China in the Early Pleistocene. We study a drill core adjacent to the classical Paleolithic Majuangou Section (about 15 meters to the drill core), which contains five horizons of human civilization. The drill core has been constrained by magnetostratigraphy to the interval of 1.2-2.1 Ma. To correlate the drill core to the Majuangou section, we conducted magnetic susceptibility analysis. The Paleolithic layers in the section and core show low magnetic susceptibility. We then apply the compound-specific hydrogen and carbon isotope analyses to terrestrial long-chain n-alkanes in the drill core sediments. The δD values fluctuate between –230.7 ‰ and –157.3‰. The δ¹³C values fluctuate between –31.2‰ and –27.0‰. Typically, low δD values and high δ¹³C values appear at the Paleolithic layers. Multiple lines of evidence suggest that before 1.2 Ma, hominid occupied Nihewan Basin in the warm interglacial periods: (1) low-magnetic units are linked to high lake level and enhanced organic productivity in interglacial periods. (2) Strong East Asia summer monsoon during interglacial periods causes low n-alkane δD values. (3) The warm climate was favorable for thermophilic conifers and C₄ plants which contribute to higher n-alkanes δ¹³C values. In combination with previous studies which suggest that hominid occupied Nihewan Basin in both glacial and interglacial periods after 1.1 Ma, our research indicates a shift of hominid adaptation at ca. 1.1 Ma, which is in step with the progress of technology in stone tools.