Phytoliths composition

Tsutsuki, K., Kondo, R. and Shiraishi, H. (1993). Composition of lignin-degradation products, lipids and opal phytoliths in a peat profile accumulated since 32,000 years B.P. in Central Japan. Soil Science and Plant Nutrition 39 463-474. 

As must be obvious, we have only touched on the natural occurrences of crystalline fibrous Si02- For example, Si02, usually quartz, often replaces fibrous minerals of another composition as rock masses are altered. Si02 also occurs in fibrous form within some plants (phytoliths) and in the soil. To summarize, in addition to the usual and common occurrences of the mineral quartz and its varieties, several silica polymorphs occur as fibers in a variety of biologic and geologic environments. 

The diversity and abundance of phytolith assemblages can be used to determine the composition of paleoplant communities. A study across the Great Plains of the US showed that modem phytolith assemblages displayed a geographic pattern consistent with modern grassland composition (Fredlund and Tieszen, 1997a). 

Because the species composition of grasslands is observed to change systematically with environmental parameters such as temperature, the study also suggested that phytolith assemblages from prehistoric grasslands could be used to reconstmct paleoclimate conditions. 

Phytolith assemblages show a clear turnover from savanna to forest ecosystems in south central Brazil 4 kya(Alexandreeta/., 1999) and indicate that the closed forest in the Amazon Basin has existed since 4.6 kya, but prior to this time the forest composition and species abundance fluctuated widely (Piperno and Becker, 1996), leading researchers to hypothesize that climate change stabilized the vegetation during the middle Holocene. 

Kelly E. E., et al. (1998) Stable isotope composition of soil organic matter and phytoliths as paleoenvironmental indicators. Geoderma 82(1-3), 59-81. 

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