Evaluation of Phytolith Production and Preservation in an Oxisol in Western Paraná, Brazil

Abstract

Phytoliths are plant micro-remains found in soils and sediments. Their durability, abundance and diagnostic morphologies make them reliable environmental proxies, especially when associated with other biological, chemical, or physical indicators. However, in some cases, phytoliths are the only biological proxy available on the soil for paleoenvironmental studies, therefore, it requires extra attention to taphonomic processes affecting these silica bodies’ assemblage. The preservation and conservation of this markers in the soil is directly linked to the edaphic conditions to which it is subjected over time. Hence, the application of this proxy requires care in order to avoid misinterpretations, since phytoliths are subject to degradation and movement within the soil due to soil-plant-water interactions, soil hydrological processes a/nd bioturbation. In this article we examine the diversity and taphonomic evidence found in an Oxisol’s phytolith assemblage in search to better our understanding of this silica bodies preservation in tropical soils. The result shows that the assembly found is very resistant to tropical edaphic conditions, displaying taphonomic signs such as breakage and corrosion across the profile, with significant increase with depth, pointing to the phytolith’s early deposition. Also, results suggest that Grass Silica Short Cell Phytolith tend to present more breakage than corrosion due to its smaller size when compared to bigger morphotypes, which have corrosion features more often.

Keywords:
Phytoliths; Taphonomy; Tropical Soils

HIGHLIGHTS

The rate of phytolith taphonomization within the soil profile tends to increase with depth.

Greater rates of non-identified taphonomized phytoliths might be associated with soil compaction.

Taphonomy effects are different on Grass Silica Short Cell Phytoliths and on larger morphotypes.