Early plant organics increased global terrestrial mud deposition through enhanced flocculation

Abstract

What matters for mudrocks Rock such as slate and shale, which form from mud, suddenly start appearing in the geologic record around 450 million years ago. Their appearance at about the same time as certain plants seems to implicate plant roots in the formation of these ubiquitous rocks. Zeichner et al. found a different route for creating the flocculation required for mudrock. Using analog experiments, the authors found that organic matter from plants alone was sufficient for the formation of flocs—aggregates of small silt and clay particles—which are required to deposit mudrock. This observation could explain the appearance of these rocks in places where the plants did not have deep roots. Science , this issue p. 526