Chlorine 36 dating method
The surface one to two metres of rock shield underlying rock from most types of cosmic radiation.When rock is plucked by a glacier from below this depth range and subsequently deposited on the surface, it begins to accumulate chlorine-36 produced by the cosmic radiation.We then examine how pre-exposure and exposure histories of fault-zone materials are expressed in [Cl approach allows unambiguous discrimination of sporadic slip versus continuous creep on these faults.It allows identification of the large slip events that have contributed to the scarp exhumation, and provides their displacement with an uncertainty of ±∼25 cm and their age with an uncertainty of ±0.5–1.0 kyr.
The quartzite that composes the erratics is extremely tough and resistant with little evidence of spalling along bedding planes.
The chlorine-36 method for surface exposure dating relies on the accumulation of the isotope chlorine-36 produced by reactions of cosmic rays with the nuclei of K, Ca, and Cl atoms.
It is one of several methods based on the accumulation of cosmogenic nuclides.
As is indicated in Table 1, some erratics did receive some pre-exposure but the resulting cosmogenic ages significantly post date the penultimate glaciation of the region.
Their large heights and the generally low relief and precipitation of the windy and treeless eastern Foothills also make it unlikely that they were initially buried and subsequently exhumed and minimize the degree to which snow or vegetation has shielded the erratics from cosmic rays.