Texas A&M anthropologist studies ancient human footprints

November 30, 2005

COLLEGE STATION, Nov. 30, 2005 - An article published in the prestigious science journal Nature and co-authored by a Texas A&M University researcher places the age of rocks found in Mexico containing possible human footprints at over 1.3 million years. The generally accepted date for the arrival of humans in North America, across a northern land-bridge from Asia, is 11,000 years ago.

But whether humans really made the marks found in the rocks in Mexico is controversial, says Michael R. Waters, director of the Center for the Study of the First Americans and an anthropology and geography professor at Texas A&M.

"We conclude that either hominid migration into the Americas occurred very much earlier than previously believed, or that the features in question were not made by humans on recently erupted ash," the Nature article states.

Waters and a consortium of researchers from California and Mexico tested the age of the rocks using radioactive isotope dating methods and paleomagnetic data and found that the basaltic rock in which the "footprints" are found is about 1.3 million years old. The resulting Nature article does not address whether the marks in the rock were made by early ancestors of modern man, although Waters says that the extreme age of the rocks containing the marks and their similarities to impressions made by quarrying equipment such as that used in the area make him doubt that early men made these "footprints."

Waters collaborated to produce this article with Paul R. Renne, Department of Earth and Planetary Science, University of California, Berkeley and Berkeley Geochronology Center, where the dating work was done; Joaquin Arroyo-Cabrales and Mario Perez- Campa of the Mexican National Institute of Anthropology and History; Patricia Ochoa Castillo of the Mexican National Museum of Anthropology; and UC Berkeley graduate students Joshua M. Feinberg and Kim B. Knight. The Berkeley Geochronology Center, located a block from the UC Berkeley campus, is recognized as one of the world's preeminent anthropological dating laboratories.

Earlier this year, researchers in England (who have yet to publish a peer-reviewed analysis of the footprints) dated the volcanic rock containing the marks at 40,000 years old and touted the "footprints" as definitive proof that humans were in the Americas much earlier than 11,000 years ago, which is the accepted date for the arrival of humans across a northern land- bridge from Asia. They hypothesized that early hunters walked across ash freshly deposited near a lake by volcanoes that are still active in the area around Puebla, Mexico. The so-called footprints, subsequently covered by more ash and inundated by lake waters, eventually turned to rock.

The rock was dated using radioactive argon at the Berkeley Geochronology Center. The argon method reliably dates rock as young as 2,000 years or as old as 4 billion years. Corroboration of the date indicated by the argon method was sought with paleomagnetic data because many rocks retain evidence of their orientation at the moment they cool in the form of iron oxide grains magnetized in a direction parallel to the Earth's magnetic field at the time of cooling. Because the Earth's field has repeatedly flipped throughout the earth's history, it is possible to date rock based on its magnetic polarity.

Waters, Renne, Knight and Mexico City archeologists visited the site at the Toluquilla quarry last year while investigating another potential early anthropological site across the reservoir.
-end-
Contact: Michael Waters, Texas A&M, 979-845-5246, mwaters@tamu.edu;
Paul Renne, Berkeley, 510-644-1350 or prenne@bgc.org;
Joaquin Arroyo-Cabrales, Instituto Nacional de Antropologia e Historia, arromatu@hotmail.com.

Texas A&M University

Related Anthropology Articles from Brightsurf:

Study finds field of forensic anthropology lacks diversity
The field of forensic anthropology is a relatively homogenous discipline in terms of diversity (people of color, LGBTQ+ individuals, people with mental and physical disabilities, etc.) and this is highly problematic for the field of study and for most forensic anthropologists.

Neandertal gene variant increases risk of severe COVID-19
A study published in Nature shows that a segment of DNA that causes their carriers to have an up to three times higher risk of developing severe COVID-19 is inherited from Neandertals.

How do Americans view the virus? Anthropology professor examines attitudes of COVID
In her latest study, Northern Arizona University professor Lisa Hardy looks at how Americans' attitudes and responses have changed during the time of the pandemic and how to many people, the virus is not a biological agent but instead a malicious actor.

Neandertals may have had a lower threshold for pain
Pain is mediated through specialized nerve cells that are activated when potentially harmful things affect various parts of our bodies.

Running in Tarahumara culture
Running in Tarahumara (Rarámuri) Culture. The Tarahumara (Rarámuri) are a Native American people from Chihuahua, Mexico, who have long been famous for running, but there is widespread incredulity about how and why they run such long distances.

The growing pains of orphan chimpanzees
Using long-term behavioral and hormonal data from wild chimpanzees in the Taï Forest, Côte d'Ivoire, researchers from the Taï Chimpanzee Project at the Max Planck Institute for Evolutionary Anthropology, have revealed that mothers may be shaping pre-adult growth and offspring muscle mass even without direct provisioning.

Caribbean settlement began in Greater Antilles, say University of Oregon researchers
A fresh, comprehensive look at archaeological data suggests that seafaring South Americans settled first on the large northernmost islands of the Greater Antilles rather than gradually moving northward from the much closer, smaller islands of the Lesser Antilles.

Human songs share universal patterns across world's cultures
From love songs to lullabies, songs from cultures spanning the globe -- despite their diversity -- exhibit universal patterns, according to a new study.

Skull features among Asian and Asian-derived groups differ significantly
Forensic anthropologists have now discovered that several skull features in Asian and Asian-derived groups differ significantly with regard to shape, such that they can be distinguished using statistical analyses.

Skull dimensions of Dominicans and Haitians differ despite close physical proximity
Researchers from Boston University School of Medicine (BUSM) have conducted a craniometric study (measuring the main part of the skull) on understudied and marginalized groups and found that skull dimensions of Dominicans and Haitians, who occupy a relatively small island of Hispaniola, are different from each other.

Read More: Anthropology News and Anthropology Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.