Archaeologist Barry Clifford believes he has discovered the remains of Christopher Columbus's ship, the Santa Maria, which was lost at sea more than 500 years ago, off the coast of Haiti.
Clifford first visited the site of the wreck in 2003, but didn't suspect its identity at the time. It took years and a number of unrelated investigations to allow Clifford to say with confidence that he believes he's found the long-gone vessel.
Dashed lines are approximate boundaries of the extent of settlement based on dated archaeological sites, and solid arrows are hypothesized population movements. A) The initial expansion into southern Siberia from central Asia is relatively uncontroversial. B) Similarly, the expansion from southern Siberia to far-western Beringia by ~30k calBP is uncontroversial. C) Three proposed pre-LGM colonization routes include coastal, terrestrial, and trans-Arctic routes, however, currently there are no archaeological sites beyond western Beringia to support these routes. D) Post-LGM models include the traditional trans-Beringian route, and a coastal route. The trans-Beringian route is the best supported by current archaeological data, and there is no archaeological evidence to suggest the coastal route was a major factor in colonization, albeit complicated by Holocene sea level rise along the Pacific Rim. However, it is entirely feasible that as colonists expanded across the Beringian mainland local groups close to the southern coast may have included aquatic resources in the diet. However, there is no evidence of full maritime cultures anywhere along the Pacific Rim until well into the Holocene.
Authors:1. Marcus J. Hamilton2. Briggs BuchananAffiliations:a. Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of Americab. Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, United States of Americac. Santa Fe Institute, Santa Fe, New Mexico, United States of Americad. Department of Archaeology, Simon Fraser University, Burnaby, Canadae. Department of Anthropology, University of Missouri, Columbia, Missouri, United States of AmericaAbstract:Understanding the dynamics of the human range expansion across northeastern Eurasia during the late Pleistocene is central to establishing empirical temporal constraints on the colonization of the Americas [1]. Opinions vary widely on how and when the Americas were colonized, with advocates supporting either a pre- or post- last glacial maximum (LGM) colonization, via either a land bridge across Beringia, a sea-faring Pacific Rim coastal route, a trans-Arctic route, or a trans-Atlantic oceanic route. Here we analyze a large sample of radiocarbon dates from the northeast Eurasian Upper Paleolithic to identify the origin of this expansion, and estimate the velocity of colonization wave as it moved across northern Eurasia and into the Americas.
The lines represent the closest path for connecting all samples according to the morphological distances between them. Red dots represent samples with Paleoamerican morphology and the brown dot represents the specimens from Zhoukoudian Upper Cave. Blue dots indicate the Late Holocene samples from East Asia, the Americas and Australo-Melanesia.
Authors:1. Mark Hubbe (a)2. Walter A. Neves (b)2. Katerina Harvati (c)Affiliations:a. Instituto de Investigaciones Arqueológicas y Museo, Universidad Católica del Norte, San Pedro de Atacama, Chileb. Laboratório de Estudos Evolutivos Humanos, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazilc. Paleoanthropology Section, Institut für Uhr- und Frühgeschichte und Archaeologie des Mittelalters and Senckenberg Center for Human Evolution and Paleoecology, University of Tübingen, Tübingen, GermanyAbstract:Discussion surrounding the settlement of the New World has recently gained momentum with advances in molecular biology, archaeology and bioanthropology. Recent evidence from these diverse fields is found to support different colonization scenarios. The currently available genetic evidence suggests a “single migration” model, in which both early and later Native American groups derive from one expansion event into the continent. In contrast, the pronounced anatomical differences between early and late Native American populations have led others to propose more complex scenarios, involving separate colonization events of the New World and a distinct origin for these groups.
The uplift of the Isthmus of Panama 2.6 million years ago formed a land-bridge that has long thought to be the crucial step in the interchange of animals between the Americas, including armadillos and giant sloths moving up into North America and relatives of modern horses, rabbits, foxes, pigs, cats, dogs, and elephants down into South America.
However, in the March 2013 issue of the Journal of Vertebrate Paleontology, researchers from the University of Florida and the Smithsonian Tropical Research institute describe fossil crocodilians that shed a surprising new light on the history of interchange and animal distributions between the Americas.
The fossils are partial skulls of two new species of caiman, relatives of alligators, who live exclusively in South America today. They were discovered in rocks dated from 19.83 and 19.12 million years old and that were exposed by excavations associated with the expansion of the Panama Canal.
"These are the first fossil crocodilian skulls recovered from all of Central America. They fill a gap in evolution between the alligators of North America and the caimans of South America. It's quite incredible." states lead author Alex Hastings, a fossil crocodilian specialist at Georgia Southern University.
The presence of the fossils in Panama indicates that caimans dispersed North from South America by the early Miocene, which is over ten million years earlier than the spread of mammals. This discovery is additionally important because caimans lack the ability to excrete excess salt from their bodies and are restricted to freshwater environments. As a result, they could have only dispersed a short distance across sea water, which supports a recent hypothesis that Central and South America were much closer to each other 19 million years ago than previously thought, and paints a new picture of the past histories of American animals.
Says co-author Jonathan Bloch, a vertebrate paleontologist at the Florida Museum of Natural History, "We are starting to understand that while the mammals in Panama 19-21 million years ago were very similar to those found in Mexico, Texas, and Florida at that time, the reptiles tell a different story. Somehow, they were able to cross over from South America when it was completely isolated by seaways—this is one of the mysteries that will drive future inquiry and research in this region."
A new study of Oregon's Paisley Caves confirms that humans used the site as early as 12,450 radiocarbon years ago, and the projectile points they left behind were of the "Western Stemmed" tradition and not Clovis – which suggests parallel technological development of early inhabitants to the Americas.
The study, published this week in the journal Science, could have a major impact on theories of how the Western Hemisphere was populated. The research was funded by multiple organizations, including the National Science Foundation.
Lead author Dennis Jenkins, from the University of Oregon, and second author Loren Davis, from Oregon State University, were part of a large multidisciplinary team that spent much of the past two years combing through deposits and collecting more than 100 high-precision radiocarbon dates from Paisley Caves, located in south-central Oregon's Summer Lake basin.
What cemented the authors' findings was a thorough examination of the stratigraphy in the caves, which confirmed that coprolites containing human DNA were definitely associated with layers of sediment ranging in age from 2,295 to 12,450 years ago – and were not contaminated by humans or animals at later dates. The researchers last year also found additional Western Stemmed projectile points.
"The Western Stemmed and Clovis traditions include different technological strategies," said Davis, an associate professor of anthropology in OSU's School of Language, Culture and Society. "The Western Stemmed artifacts from Paisley Caves are at least as old – and may predate – the oldest confirmed Clovis sites, indicating that the peopling of the Americas was at least technologically divergent, if not genetically divergent."
The projectile points were found in deposits dating back to 11,070 to 11,340 radiocarbon years ago, and thus were not quite as old as the oldest coprolites. But DNA from coprolites of that era was similar to that found in the oldest coprolites, Davis pointed out. "They were from the same genetic group," he said.
The difference in technology between Clovis and Western Stemmed projectile points revolves around how they were attached to spears, which relates to the strategy of finding and shaping pieces of rock in the first place. Clovis artifacts have a distinct notch at the base, where a piece has been removed. The tool builder starts with a large rock and reduces it considerably.
Western Stemmed points and Clovis points primarily differ in the construction of their hafting portions, Davis said. Stemmed points bear constricted bases, while the hafting element of a Clovis point is thinned through the removal of a large flake from the base. Western Stemmed points are also often made by modifying smaller flakes in a different way than Clovis peoples manufactured their spear points.
"These two approaches to making projectile points were really quite different," Davis said, "and the fact that Western Stemmed point-makers fully overlap, or even pre-date Clovis point makers likely means that Clovis peoples were not the sole founding population of the Americas."
Clovis technology has only been found in the New World, while Western Stemmed technology can be related to archaeological patterns seen in northeastern Asia.
"We seem to have two different traditions co-existing in the United States that did not blend for a period of hundreds of years," said the University of Oregon's Jenkins.
Past studies of Paisley Caves also have reported on human coprolites with ancient DNA, but questions arose about whether those samples could have been contaminated, and whether they were found in context with artifacts from the same era. So the researchers did an exhaustive examination of the stratigraphy, which is one of Davis' specialties.
Davis conducted microscopic analysis of the soil structure using a petrographic microscope to eliminate signs of liquid – such as water or urine from humans or animals – moving downward through the soil. The team also carefully analyzed the silt lens where the stem points were found and bracketed above and below those layers to see if radiocarbon dates synchronized.
"The stemmed points were in great context," Davis said. "There is no doubt that they were in primary context, associated with excellent radiocarbon dates."
The earliest models for peopling of the Americas suggest that the first inhabitants arrived from Asia via a land bridge at the end of the last Ice Age and fanned out across the continent. However, those models can't explain the presence of two separate and distinct stone tool technologies at the end of the last glacial period.
"Given these recent results from Paisley Caves, it's clear that we need to come up with some better models," Davis said.
Ancient trash heaps gave rise to Everglades tree islands
Garbage mounds left by prehistoric humans might have driven the formation of many of the Florida Everglades' tree islands, distinctive havens of exceptional ecological richness in the sprawling marsh that are today threatened by human development.
Tree islands are patches of relatively high and dry ground that dot the marshes of the Everglades. Typically a meter (3.3 feet) or so high, many of them are elevated enough to allow trees to grow. They provide a nesting site for alligators and a refuge for birds, panthers, and other wildlife.
Scientists have thought for many years that the so-called fixed tree islands (a larger type of tree island frequently found in the Everglades' main channel, Shark River Slough) developed on protrusions from the rocky layer of a mineral called carbonate that sits beneath the marsh. Now, new research indicates that the real trigger for island development might have been middens, or trash piles left behind from human settlements that date to about 5,000 years ago.
These middens, a mixture of bones, food discards, charcoal, and human artifacts (such as clay pots and shell tools), would have provided an elevated area, drier than the surrounding marsh, allowing trees and other vegetation to grow. Bones also leaked phosphorus, a nutrient for plants that is otherwise scarce in the Everglades.
"This goes to show that human disturbance in the environment doesn't always have a negative consequence," says Gail Chmura, a paleoecologist at McGill University in Montreal, Canada, and one of the authors of the study.
Chmura will be presenting her research tomorrow, Tuesday 22 March, at the American Geophysical Union's Chapman Conference on Climates, Past Landscapes, and Civilizations. About 95 scientists have converged on Santa Fe this week to discuss the latest research findings from archeology, paleoclimatology, paleoecology, and other fields that reveal how changes in regional and global climate have impacted the development and fates of societies.
Study shows Native Americans modified American landscape years prior to arrival of Europeans
A new study by Baylor University geology researchers shows that Native Americans' land use nearly a century ago produced a widespread impact on the eastern North American landscape and floodplain development several hundred years prior to the arrival of major European settlements.
The study appears on-line in the journal Geology.
Researchers attribute early colonial land-use practices, such as deforestation, plowing and damming with influencing present-day hydrological systems across eastern North America. Previous studies suggest that Native Americans' land use in eastern North America initially caused the change in hydrological systems, however, little direct evidence has been provided until now.
The Baylor study found that pre-European so-called "natural" floodplains have a history of prehistoric indigenous land use, and thus colonial-era Europeans were not the first people to have an impact on the hydrologic systems of eastern North America. The study also found that prehistoric small-scale agricultural societies caused widespread ecological change and increased sedimentation in hydrologic systems during the Medieval Climate Anomaly–Little Ice Age, which occurred about 700 to 1,000 years ago.
"These are two very important findings," said Gary Stinchcomb, a Baylor doctoral candidate who conducted the study. "The findings conclusively demonstrate that Native Americans in eastern North America impacted their environment well before the arrival of Europeans. Through their agricultural practices, Native Americans increased soil erosion and sediment yields to the Delaware River basin."
The Baylor researchers found that prehistoric people decreased forest cover to reorient their settlements and intensify corn production. They also contributed to increased sedimentation in valley bottoms about 700 to 1,000 years ago, much earlier than previously thought. The findings suggest that prehistoric land use was the initial cause of increased sedimentation in the valley bottoms, and sedimentation was later amplified by wetter and stormier conditions.
