Cation-ratio Dating of Petroglyphs Using Pixe
نویسندگان
چکیده
A central problem in archaeological research has been the chronometric dating of petroglyphs (rock engravings). Recent improvements in the understanding of the chemistry of rock varnish (or patina) that develops on rock surfaces in arid regions has resulted in the development of a calibrated dating technique, cation-ratio (CR) dating. This is based on calibrating chemical changes in minor and major trace elements in the varnish over time. PIXE is used to determine the bulk chemical constituents of small samples of varnish mechanically removed from within petroglyphs. Recent applications in western North America have yielded petroglyph dates of great importance in understanding the origins of art and the antiquity of human settlement in the western hemisphere. In particular the CR dates on petroglyphs suggest that humans moved into the New World about 10 K yrs earlier than previously believed, and that the making of petroglyphs was one of the most ancient and long-lived cultural traditions in aboriginal North America
منابع مشابه
Dating Petroglyphs from Fugoppe Cave, Japan
For over 20 years, I have tried to establish a relative date for petroglyphs in Fugoppe Cave, Japan. Unsuspected amidst debris accumulating from about 1300 years ago, the petroglyphs were rediscovered accidentally in 1950. From an analysis of petroglyphs on fallen rocks scattered randomly on the site floor, I argue that the artworks date from ca.1900 years ago. The cave itself, formed by wave a...
متن کاملPetroglyphs in Petrified Forest National Park: Role of Rock Coating in as Agents of Sustainability and as Indicators of Antiquity
Rock coatings formed on petroglyphs at Petrified Forest National Park both preserve the art from erosional processes and provide tools to understand the art’s chronology. Erosional processes of rock fall from fissuresol wedging, splintering of sandstone, and flaking are somewhat offset by case hardening surfaces by addition of rock coatings. 20th century graffiti can be distinguished from truly...
متن کاملCation-Ratio Dating: A New Rock Varnish Age-Determination Technique
Rock varnish coats many surfaces of geomorphic and archaeologic interest in arid lands. All varnish dating techniques are limited by the time lag between the exposure of a surface to subaerial processes and the onset of varnishing. They are valid only where manganese is not remobilized after deposition, for example, in most arid environments. The premise of a new age-determination method, catio...
متن کاملA pixe analysis for measuring the trace elements concentration in breast tissue of Iranian women
Background: A powerful and improved technique, Proton Induced X-ray Emission (PIXE) has been performed-yielding the elemental composition of 17 samples of surgically excised malignant and normal tumors of breast tissue. The samples without any further process as thick targets were put on capton foil backing. There are no homogenizing processes. The PIXE spectra analysis was performed using he n...
متن کاملUse of PIXE–PIGE under variable incident angle for ancient glass corrosion measurements
Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive to this problem. The glass surface absorbs moisture from its environment and the contact with CO2 causes Na2O and NaOH to convert to Na2CO3, which is extremely hygroscopic. The subsequent unst...
متن کامل