南极半岛海洋气候区的土壤 Ⅶ.矿物学特性

SOILS IN THE MARITIME ANTARCTIC Ⅶ. MINERALOGY

南极海洋气候区岩石风化和土壤形成过程中有明显的原生矿物蚀变作用和自生矿物成矿作用。本文以粗骨寒冻灰化土和石灰性扰动冻土两种有代表性的土壤类型为例,阐述了本区土壤矿物学特征。指出铝氧化物、绿泥石、碳酸盐是本区玄武岩类风化物质上发育土壤中的主要自生矿物类型,蒙脱石、特别是绿泥-蒙脱石混层矿物是南极海洋气候区土壤粘粒部分的特征矿物。不同土壤由于成土环境、成土过程、成土历史的差异,其土壤物质的矿物学组成、含量、形态、分布具有明显不同。土壤发生性铁氧化物与成土作用和土壤过程密切相关,其矿物类型、含量、形态特征、分布模式在不同的土壤中明显不同,是表征土壤发育程度与剖面形态表达的有效指标。

In the maritime Antarctic region, alteration of primary minerals and formation of authigenic minerals evidently occur in the soils during rock weathering and soil-forming processes. Taking two representative types of soils, skeleti-gelic podzol and calcari-turbic cryosol, as examples, the paper addresses characteristics of soil mineralogy. It was pointed that secondary Fe-, Al-oxides in a variety of chemical compositions and morphological features, chlorites, carbonates were dominant authigenic minerals of the soil material. And, in the clay fractions of the soils, mineralogy was characterized by smectite and smecite-chlortie (I/S mixed minerals). It was stated that, due to variation of pedogenic environmental factors and differences in soil-forming processes and soil evolution history, mineralogical attributes of different soils, such as mineral constitutions, content levels and distribution patterns, varied significantly. Finally, pedogenic Fe-oxide formation was thought to be tightly linked with soil-forming processes, and therefore could be used as an effective index indicating genesis and development of soils.