Archaeologists excavating Tam Pà Ling (Cave of Monkeys) in northeastern Laos have recovered fossil evidence for some of the earliest Homo sapiens presence in mainland Southeast Asia.
Excavations in Tam Pà Ling, northeastern Laos. Image credit: Hernandez et al., doi: 10.1016/j.quascirev.2024.108982.
“Using a technique known as microstratigraphy, we were able to reconstruct the cave conditions in the past and identify traces of human activities in and around Tam Pà Ling,” said Flinders University Ph.D. candidate Vito Hernandez.
“This also helped us to determine the precise circumstances by which some of the earliest modern human fossils found in Southeast Asia were deposited deep inside.”
Microstratigraphy allows scientists to study dirt in its smallest detail, enabling them to observe structures and features that preserve information about past environments and even traces of human and animal activity that may have been overlooked during the excavation process due to their minuscule size.
The human fossils discovered by the archaeologists were deposited in the Tam Pà Ling cave between 86,000-30,000 years ago.
However, until now, they had not conducted a detailed analysis of the sediments surrounding these fossils to gain an understanding of how they were deposited in the cave or the environmental conditions at the time.
The new findings reveal conditions in the cave fluctuated dramatically, going from a temperate climate with frequent wet ground conditions to becoming seasonally dry.
“This change in environment influenced the cave’s interior topography and would have impacted how sediments, including human fossils, were deposited within the cave,” said Flinders University’s Dr. Mike Morley.
“How early Homo sapiens came to be buried deep within the cave has long been debated, but our sediment analysis indicates that the fossils were washed into the cave as loose sediments and debris accumulating over time, likely carried by water from surrounding hillsides during periods of heavy rainfall.”
The reseacrhers also identified preserved micro-traces of charcoal and ash in the cave sediments, suggesting that either forest fires occurred in the region during the drier periods, or that humans visiting the cave may have used fire, either in the cave or near the entrance.
“This research has allowed our team to develop unprecedented insights into the dynamics of our ancestors as they dispersed through the ever-changing forest covers of Southeast Asia, and during periods of variable regional climate instability,” said Dr. Fabrice Demeter, a paleoanthropologist at the University of Copenhagen.
The results were published October 10 in the journal Quaternary Science Reviews.
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V.C. Hernandez et al. Late Pleistocene-Holocene (52-10 ka) microstratigraphy, fossil taphonomy and depositional environments from Tam Pà Ling cave (northeastern Laos). Quaternary Science Reviews, published online October 10, 2024; doi: 10.1016/j.quascirev.2024.108982
