摘要
根据元素含量、K2O/Na2O、K2O/CaO、Al2O3/Na2O、CIA及ACNK图解等指标对长江下游地区下蜀土的化学风化作用进行了研究。下蜀土比西北黄土经历了较强的化学风化过程,Ca、Sr、Na和Mg大量迁移淋失,不仅表现为碳酸盐矿物的迅速风化,而且硅酸盐矿物如斜长石也明显风化,脱Ca、Na过程显著,而钾长石的风化很弱,脱K不明显。下蜀土与西北黄土的原始沉积物具有相似的化学组成。下蜀土较强的化学风化过程可能受长江下游地区较强的季风性气候控制。
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.
出处
《地球化学》
CAS
CSCD
北大核心
2001年第4期402-406,共5页
Geochimica
基金
国家自然科学基金(49976016)
