More confidently, there is a consensus that the initial immigrants where behaviorally modern, in the archaeological sense of these terms (e.g., ).
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]).
But simple and complex geometric designs are typical (roughly one-third of the total) and are frequently intermingled with the ostensibly identifiable images.
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.
The CR technique was developed by Dorn and first applied to petroglyphs in the early 1980s [24–27, 29–31, 35–38].
Though initially employed in the Americas, it was subsequently used in South America, Africa, Asia, and Australia (discussed below).
The result is evidence for the development of regional cultural diversity in the Americas by Paleoindian times.