Both the physical geologists and paleontologists could point to evidence that much more time was needed to produce what they saw in the stratigraphic and fossil records.As one answer to his critics, Kelvin produced a completely independent estimate -- this time for the age of the Sun.After its introductionto the scientific community in 1950, it quickly became the method most frequently used to determine the age of organic materials.
Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominin footprints, preserved in volcanic ash.
The site of the Laetoli footprints (Site G) is located 45 km south of Olduvai gorge.
Relative dating methods were the first dating techniques to be developed, and are still widely used.
The radiocarbon dating method was developed in the late 1940's by Dr. Libby, who later won a Nobel Prize in chemistry for this work.
Terry Harrison of New York University, leading to the recovery of more than a dozen new hominin finds, Dated to 3.7 million years ago, they were the oldest known evidence of hominin bipedalism at that time.
Subsequently, older Ardipithecus ramidus fossils were found with features that suggest bipedalism.
The location and tracks were discovered by archaeologist Mary Leakey in 1976, and were excavated by 1978.
Based on analysis of the footfall impressions "The Laetoli Footprints" provided convincing evidence for the theory of bipedalism in Pliocene hominins and received significant recognition by scientists and the public.
With the footprints there were other discoveries excavated at Laetoli including hominin and animal skeletal remains.
Analysis of the footprints and skeletal structure showed clear evidence that bipedalism preceded enlarged brains in hominins.
Radiocarbon dating is based on the fact that a radioactive isotope of carbon( Potassium argon dating is an absolute dating technique that can be used on volcanic rocks.