Central Asia has long been considered an important region for the study of human evolution. Many early human ancestors, including homo erectus and homo heidelbergensis, have been found in the region, which is believed to have been a key area of human evolution and migration due to its location at the crossroads of Europe, Asia, and Africa. Additionally, the region is home to a number of important archaeological sites, such as the Denisova Cave in Siberia, which have yielded valuable insights into human evolution and behavior.
According to a new study on early human migration, semi-arid and desert zones of Central Asia may have played an important role in the dispersal of hominins into Eurasia during the Middle Pleistocene. Central Asia is located at a crossroads that connects several zones important for hominin dispersal during this time period, but much evidence from this region lacks context for dating and climate conditions, making it difficult to understand these dynamics.
A new study led by Dr. Emma Finestone, Assistant Curator of Human Origins at the Cleveland Museum of Natural History and Research Affiliate of the Max Planck Institute for Science of Human History, has identified the interior of Central Asia as a key route for some of the earliest hominin migrations across Asia.
The study’s findings indicate that the steppe, semi-arid and desert zones of Central Asia were once favorable environments for hominins and their dispersal into Eurasia.
An interdisciplinary team of scholars from institutions that span four continents set out to expand the limited knowledge of early hominin activity in the Central Asian lowlands. The team included Dr. Paul Breeze and Professor Nick Drake from Kings College London, Professor Sebastian Breitenbach from Northumbria University Newcastle, Professor Farhod Maksudov from the Uzbekistan Academy of the Sciences, and Professor Michael Petraglia from Griffith University in Queensland, Australia.
Central Asia connects several zones that played important roles in hominin dispersals out of Africa and through Asia. Yet we know comparatively little about the early occupation of Central Asia.Dr. Finestone
“Central Asia connects several zones that played important roles in hominin dispersals out of Africa and through Asia” Dr. Finestone said. “Yet we know comparatively little about the early occupation of Central Asia. Most of the archaeological material is not dated and detailed paleoclimate records are scarce, making it difficult to understand early hominin dispersal and occupation dynamics in that region.”
The researchers gathered and analyzed Pleistocene (ca. 2.58 million to 11,700 years ago) paleoclimatic and archaeological data from Central Asia. This included creating a database of Paleolithic stone tools and analyzing a mineral deposit (a stalagmite) that formed in a cave in southern Uzbekistan. Making and modifying tools is critical to humans’ ability to adapt to new environments and overcome environmental challenges. As ancient hominins dispersed, they took their tools with them. The researchers looked at the location of stone tools and the environmental conditions reflected in the stalagmite as it grew around 400,000 years ago, at the end of the Marine Isotope Stage 11 (a warm period between glacials MIS 12 and MIS 10).
Dr. Maksudov from the Uzbekistan Academy of the Sciences said relatively little is known about the region’s earliest toolmakers because the majority of Lower Paleolithic (the earliest subdivision of Paleolithic stone tools) occurrences in Central Asia lack reliable context for dating and environmental reconstruction.
“Despite the potential importance of Central Asia in early dispersals, we know very little about the Lower Paleolithic in this vast and diverse landscape. We compiled data on Paleolithic discoveries from across Central Asia, resulting in the largest dataset of its kind, with 132 Paleolithic sites” Professor Petraglia, a senior author on the study, elaborated. “This allowed us to consider the distribution of these sites in the context of a new high-resolution speleothem-based multi-proxy record of Middle Pleistocene hydrological changes in southern Uzbekistan.”
“Cave deposits are incredible archives of the environmental conditions that existed at the time of their formation. We gain insights into seasonal to millennial-scale changes in moisture availability and the climatic dynamics that governed rain and snowfall by using geochemical data from stalagmites. Our findings indicate that local and regional conditions were highly variable, rather than following simple long-term trends” Professor Breitenbach, who led the stalagmite-based analysis, explained.
“We argue that Central Asia was a favorable habitat for Paleolithic toolmakers when warm interglacial phases coincided with periods of consistently high Caspian Sea water levels, resulting in greater moisture availability and more temperate conditions in otherwise arid regions,” Dr. Finestone said. “The patterning of stone tool assemblages backs this up.”
The local environment of arid Central Asia may have been a favorable habitat during periodic warmer and wetter intervals and was frequented by Lower Paleolithic toolmakers producing bifaces (stone tools that have been worked on both sides).
“Interdisciplinary work that connects archaeology and paleoclimate models is becoming increasingly important for understanding human origins,” Dr. Finestone said. “The databases generated in this study will continue to allow us to ask questions about the context of hominin dispersals in the future.”