Tam Pà Ling Cave | 01 Jul 2023
Why in News?
Tam Pà Ling Cave in the Annamite Mountain range in Northern Laos has recently provided groundbreaking insights into the timeline of human arrival in Southeast Asia.
- Tam Pà Ling Cave features a sloping structure formed by periodic slope wash deposition.
What are the Key Findings in Tam Pa Ling Cave?
- Prolonged Human Presence: The excavation revealed evidence suggesting that humans have inhabited the vicinity of Tam Pà Ling Cave for approximately 56,000 years, challenging previous assumptions.
- Steady Sediment Accumulation: Contrary to earlier beliefs, the site's sediment layers accumulated steadily over an estimated period of 86,000 years, rather than through rapid sedimentation events.
- Arrival Timeline: The discovery of a leg bone fragment, found seven meters deep, indicates that modern humans arrived in the region between 86,000 and 68,000 years ago.
- The evidence from Tam Pà Ling has pushed back the timing of Homo sapiens' arrival in Southeast Asia.
- Denisovan Connection: Remarkably, a tooth, estimated to be 150,000 years old, was found in the Cave, linking it to the presence of Denisovans, an extinct human relative.
Denisovans:
- Extinct Human Relatives: Denisovans represent a distinct human lineage, primarily known from remains discovered in Siberia and Tibet.
- Interbreeding and Coexistence: They lived hundreds of thousands of years ago, overlapped with Neanderthals in some regions, and interbred with early modern humans, leaving traces of their genetic heritage in present-day human populations.
- Denisovan Cave: The identification of Denisovans was made following the discovery of fragmentary finger bone and teeth dating back approximately 40,000 years, found in the Denisovan Cave in Siberia.
What are the Dating Methods Used in Tam Pà Ling Cave?
- Luminescence Dating: Utilizes light-sensitive signals in buried sediment. It relies on minerals like quartz and feldspar.
- Quartz used to date the younger levels (top three meters of sediment).
- Feldspar is used for dating the lower levels (four to seven meters) where quartz is limited.
- Uranium Series Dating: Measures uranium and its decay products within a tooth or other samples.
- Electron Spin Resonance (ESR) Dating: Measures the number of electrons in tooth enamel which provides numerical age for the fossil based on the accumulation of trapped electrons over time.
- Sediment Dating: Determines the age of the sediment layers themselves, providing a framework for understanding the fossils found within. It relies on techniques like luminescence dating, uranium series dating, and micromorphology analysis (examines sediments under a microscope to establish the integrity of the layers).