Early Man - Summer 2020

1. MEXICO Mexican Cave Find Hints That People Lived in North America 30,000 Years AgoIn a lofty cavern, archaeologists discover spear points, other implements that indicate people were living in North America earlier than previously believed Scientists said they unearthed hundreds of unusual green limestone spear points, blades and other implements from the Chiquihuite Cave.By Robert Lee Hotz Wall Street Journal July 22, 2020 11:00 am ET Archaeologists in Mexico found stone tools and other signs that people were living in North America 30,000 years ago, much earlier than widely believed, according to new research reshaping the debate over the origins of people in the Americas.In a study reported Wednesday, scientists led by archaeologist Ciprian Ardelean at Mexico’s University of Zacatecas said that they had unearthed hundreds of unusual green limestone spear points, blades and other implements from a lofty cavern in the central Mexican highlands. For wandering hunter-gatherers, the cave served as a makeshift tool shed possibly beginning as early as about 33,000 years ago, the scientists said.These new finds at Chiquihuite Cave, located almost 9,000 feet above sea level and about 400 miles northwest of Mexico City, are the latest in a series of discoveries across North and South America that have archaeologists pushing humankind’s entrance into the Americas deeper into antiquity. The discoveries in Mexico were published in the journal Nature.“It is a fundamental change in our way of thinking,” said anthropologist Ruth Gruhn, an emeritus professor at the University of Alberta who helped pioneer studies of early migrations into North and South America. She wasn’t involved in the find. “Dates of around 30,000 years ago indicate that people have been on both continents twice as long as generally believed.” Migration into the Americas Recent excavations at a cave in Mexico add to evidence that settlement of the American continent began some 10,000 years earlier than previously thought Sources: the journal Nature (Chiquihuite cave, early human settlements); Geological Survey of Canada (ice sheets); Paleoindian Database of the Americas (late Pleistocene coastline)For most of the 20th Century, archaeologists were convinced that big-game hunters known as the Clovis people, identified by the fluted flint spear points they made, were the first Americans, arriving about 12,000 to 13,000 years ago. More recent finds from Oregon to Chile, though, showed that other groups had arrived 16,000 years ago or more.In fact, a new analysis of 42 early archaeological sites by radiocarbon dating expert Lorena Becerra-Valdivia at the University of New South Wales in Australia, also published Wednesday in Nature, established that North America was widely settled by 15,000 years ago.“Humans were present in North America a lot earlier than we thought,” Dr. Becerra-Valdivia said. “It points to a complex and really interesting peopling process.”To have reached Mexico by around 30,000 years ago, however, the footloose first Americans must have traveled from Asia into North America thousands of years earlier, either across a land bridge or by sea along the coast, several scientists said. It is considered unlikely they came directly across the open ocean. ”I think we are looking at the first people coming by 40,000 years ago or so,” Dr. Gruhn said.For a decade, Dr. Ardelean searched the state of Zacatecas for evidence of such early human settlement. He explored 35 sites with no luck. In 2010, local villagers told him of the remote Chiquihuite Cave. When Dr. Ardelean and his colleagues first ventured into its inky interior, he expected little more than a coyote den.He was surprised to discover two vast vaulted interconnected chambers steeply sloping down into the heart of the mountain. “We were shocked by the size of everything,” he said.In 2012, they dug a test pit in the loosely compacted gravel, sand and fragmented rock about 150 feet from the cave entrance. The deeper they dug, the harder it was to keep the walls of the pit from collapsing. “When I left the cave, I was convinced I had nothing,” he said. “I had several bags of rocks with me that somehow looked suspicious.”The Chiquihuite Cave served as a makeshift tool shed possibly beginning as early as about 33,000 years ago, scientists said.PHOTO: DEVLIN A. GANDYIn the laboratory, they identified three hand-flaked stone chips created during toolmaking, the charred remains of palm plants and the bone from a bear’s penis. Radiocarbon dating of the bone and charcoal suggested they might be around 27,000 years old, he said.“That rang the alarm,” he said.In three years of fieldwork, they recovered more than 1,900 tools made from small distinctive chunks of greenish limestone not normally found inside the cave. The sharpened points, blades and scrapers had been crafted with soft hammer blows, likely from a wooden or bone striker, Dr. Ardelean said. They looked like nothing else he had seen in the Americas.The researchers found ample genetic evidence of plants and animals in the mix of sediments, but no human DNA. “Without DNA, I cannot say who they are or who they are related to, whether they are from the north or from the south,” Dr. Ardelean said.To estimate the age of the cave finds, the scientists conducted 46 radiocarbon tests using samples of bone, charcoal and plant matter, and six tests with a technique called optically stimulated luminescence that can date minerals. The most recent tool-bearing level was about 13,000 years old. The oldest layer was between 33,150 and 31,405 years old, the scientists said.At least three different groups migrated to the Americas in the first waves of settlement, scientists said. But these earliest inhabitants of central Mexico seem to have little in common with them, because they lived at such high altitude, which the other three didn’t, and because their tools were so different. Indeed, there may have been many other as yet undiscovered groups among these earliest Americans who don’t fit academic preconceptions about our past, Dr. Ardelean said.“They were much more diverse culturally and probably genetically than we are eager to accept today,” said Dr. Ardelean. “There may be a great diversity of people hiding under our misconceptions. .”https://www.wsj.com/articles/mexican-cave-find-hints-that-people-lived-in-north-america-30-000-years-ago-11595430002?st=rv8it2thbyjoy5f&reflink=article_email_share