Age and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36Cl and 14C in rock varnish

Using cosmogenic ³⁶Cl buildup and rock varnish radiocarbon, we have measured the exposure age of rock surfaces at Meteor Crater, Arizona. Our ³⁶Cl measurements on four dolomite boulders ejected from the crater by the impact yield a mean age of 49.7 ± 0.85 ka, which is in excellent agreement with an average age of 49 ± 3 ka obtained from thermoluminescence studies on shock-metamorphosed dolomite and quartz. These ages are supported by undetectably low ¹⁴C in the oldest rock varnish sample.