Start Rock varnish dating

Rock varnish dating

Arrowsmith described his project, started last autumn, as “a quick way” of trying to “show these particles could be found” in rock.

The rock-dating techniques developed by a geographer at Arizona State University (ASU) have again been called into question as a detailed analysis published last week strongly suggested that some of the results may have been fabricated.

Although these changes were attributed to the preferential leaching of Ca and K from varnish, the existence of such leaching has not been demonstrated.

In varnish collected from the Cima volcanic field, California, distributions of the minor elements used in cation-ratio (CR) dating reflect varnish stratigraphy as defined by the major elements Mn, Fe, and Si.

The article in Science revealed that an analysis by two AMS laboratories found pieces of coal and/or charcoal-like material in about 80 of Dorn's samples from previous projects.

The coal and charcoal have widely disparate radiocarbon dates, say the scientists, who also are from Columbia University's Lamont Doherty Earth Observatory, Northern Arizona University and Eidgenössische Technische Hochschule in Switzerland.“If you have a sample mixture of two different ages, it will not yield a reliable age, just a measure of a ratio for the age of the two components,” says J.

In particular, Dorn cites an unpublished article by ASU geologist J.

Ramon Arrowsmith, who Dorn writes “replicated in an independent study” his work after being “trained in sample collection and preparation procedures”.

The Arizona scientists say they found pieces as large as 1 mm across.