Site ul gratuit de dating in Madagascar
It is considered as one of the most significant records of Late Quaternary environmental and climatic change in the region. Age information for the sequence was previously obtained through time—depth modeling of magnetic susceptibility data and optically stimulated luminescence dating OSL of fine silt-sized 4—11 μm quartz. This study documents the granulometric properties of the sequence, and compares the OSL characteristics and age of fine sand-sized 63—90 μm quartz to those of silt-sized quartz.
OSL signals from both sand and silt-sized quartz are dominated by a thermally-stable fast decaying component. A suite of laboratory test confirms that the single-aliquot regenerative dose SAR protocol is suitable for these samples.
Each grain-size fraction yields a set of optical ages that is consistent with the stratigraphic position of the samples. The discrepancy in age results is not understood as, according to procedural tests, the OSL signal from both fractions should be suitable for dating the deposits.
Both sets of ages do confirm, however, that the first well-developed palaeosol S1 is of Last Interglacial age.