Geochemical records of chemical weathering of the Xiashu Loess in the lower reaches of the Changjiang River

Chemical weathering of the Xiashu Loess at three localities in the lower r eaches of the Changjiang River is studied in detail on basis of eleme ntal contents,K 2 O /Na 2 O,K 2 O /CaO  ,Al 2 O 3 /Na 2 O,CIA and A 2 CN 2 K dia-gram.The results show that chemical weathering underwent by the Xiashu L oess is much stronger than that by the typical loess in Northwest China,an d Ca,Sr,Na and Mg are much leached out .Chemical weathering indexes prove that not only carbonates in the Xiashu Loess underwent rapid weathering,but also silicate minerals,su ch as plagioclase,experienced obvious weathering with much leach of Ca and Na ,whereas K-feldspar went through we ak weathering and K was less leached.We athering trends of the Xiashu Loess a nd the loess in NW China are very similar,reflecting close chemical compositions of their weathering mo ther materials.Strong chemical weathering underwent by the Xiashu loess might be related to strong monsoon climate i n the lower reaches of the Changjiang River.