For the past quarter century, husband-and-wife paleoecologists David Burney and Lida Pigott Burney, along with dozens of colleagues and volunteers, have been digging down through the black mud that fills the sinkhole.
"Theoretical date marking the beginning of another Maha Yuga, or Great Age [traditionally a cycle of 4,320,000 years] and the beginning of the world's most recent Satya Yuga [Also: Krta Yuga, Krita Yuga], or Golden Age [traditionally a cycle of 1,728,000 years]." [- E.
The Mladeč samples date to around 31,000 years ago, reports Eva Maria Wild from the VERA (Vienna Environmental Research Accelerator) Laboratory at University of Vienna, where the radiocarbon dating has been performed.
Ideal conditions within an ancient cave system are revealing a rich history that reaches back to a time before humans settled the island and extends to the present day By ANDREW LAWLER Friday, April 03, 2015 Some six million years ago, in the middle of the North Pacific Ocean, volcanic activity bubbling up from deep beneath the Earth’s crust formed Kauai, the most ancient of Hawaii’s major islands.
Wedged in a crease of hills just above a long white-sand beach favored by sailboarders, the sinkhole sits in a setting so picturesque that Johnny Depp’s Captain Jack Sparrow leaped off the lip of one of its high cliffs in the recent .
There, everything from a 352,000-year-old lava flow to a Styrofoam cup washed in during a recent hurricane has been preserved.
It also created what would turn out to be a unique and fortuitous set of conditions that preserved a long, dramatic story of geological change and biological invasions, and of the waves of humans that successively altered the island in radical ways.
Paleoecologists and archaeologists working there, surrounded by the high, ancient limestone walls, are beginning to read that record.
Rainwater flowed down the mountains, and, as that runoff reached the Mahaulepu Valley on the island’s southeast coast, it encountered fossilized sand dunes, where, through a process called dissolution, a network of caves was formed.
As temperatures increased in the transition between the Pleistocene and Holocene eras, the glaciers melted and the oceans rose, turning big islands into small islands and shrinking animals’ habitats. Angel Soto-Centeno of the American Museum of Natural History and David Steadman, a University of Florida ornithologist, set out to unravel this story.
If extinctions were driven by climate change, they would expect to see radiocarbon-dated fossils of extinct bats from the era known as the Pleistocene-Holocene Transition, and paleoclimate evidence should clearly show changes in available habitat — like the submergence of caves.
Several previous attempts to radiocarbon date the Mladeč specimens directly have failed, but in the present attempt by using teeth as dating material reliable results were obtained.
The findings are now documented in a recent issue of Nature.