Sulfur isotopic compositions of individual sulfides in Martian meteorites ALH84001 and Nakhla: implications for crust¯regolith exchange on Mars

Here, we present a refined timescale for the entire sequence of Quaternary Chinese loess, which relies upon the correlation of detailed monsoon records to the astronomical solution of Laskar (1990) and the oceanic ODP677 delta18O record of Shackleton et al. (1990). The chronological scheme considers in detail the relative structures of the palaeoclimatic and palaeomagnetic records to produce an accurate timescale that is consistent with the current understanding of loess depositional and post-depositional processes. Analysis of this chronological framework demonstrates downward displacement of the palaeomagnetic horizons with respect to the climatic record.