Unit dating controversy
This question is addressed starting with a reconsideration of rock varnish chronometrics as applied to Great Basin, eastern California, petroglyphs.
A key attribute of archaeological modernity is the ability to conceptualize and employ symbols, including the capacity to make and use art .One result is the fact that this widespread corpus is sometimes labeled the “Great Basin Archaic Style” (e.g., ) although, as we shall see, it was neither solely nor predominantly produced during the Great Basin Archaic period (circa 5000–1000 YBP).Any discussion of potential early art requires a consideration of dating; in this case, rock art chronometrics and much of the early rock art chronometrics research was conducted in the Coso Range and Mojave Desert (e.g., [24–28]).Although rarely considered, early art has the potential to provide insight into questions that may be obscured by other kinds of evidence, particularly stone tools.What part did art play in the peopling of the Americas?By the mid-1990s, three independent rock varnish dating techniques had been developed and applied to petroglyphs: cation-ratio (CR) dating, varnish microlamination (VML) dating, and AMS ; one result of which is the widespread but incorrect assumption among archaeologists that rock varnish dating as a whole is no longer viable .
Although AMS-WRO dating is in fact currently unusable [33, 34], the controversy strictly had no implications for the other techniques, and significant geomorphological research on them has occurred in the interim.
This necessarily requires a discussion of recent advances in petroglyph dating techniques before turning to the larger issues at hand.
Great Basin petroglyphs are well known due to influential early syntheses of this art [11, 12].
These studies are summarized below with the intent of providing a hemisphere-wide overview of early symbolic behavior.
My point of departure in this discussion is a chronometric reanalysis of Great Basin petroglyphs (rock engravings), directed specifically at identifying the earliest art in far western North America.
Figure 1: Mojave Desert, California, rock engravings are predominated by images of bighorn sheep, followed numerically by anthropomorphic figures and next by a variety of geometric forms.