Usselo is the type site for the 'Usselo Soil', which is also known as either the 'Usselo horizon' or 'Usselo layer'. It is a distinctive and widespread
Weichselian (Lateglacial) buried soil,
paleosol, that is found within Lateglacial
eolian sediments known as 'cover sands' in the Netherlands, western Germany, and western Denmark. This paleosol is classified as either a weakly podzolized Arenosol or as a weakly podzolized Regosol. Numerous
radiocarbon dates,
optically stimulated luminescence dates,
pollen analyses, and archaeological evidence from a number of locations have been interpreted to show that the Usselo Soil formed as the result of
pedogenesis during a period of landscape stability during the
Allerød oscillation. Locally, the period of landscape stability and pedogenesis associated with the formation of the Usselo Soil continued into the
Younger Dryas stadial. The 'Usselo Soil' is an extremely important and very useful
marker bed that is used by European archaeologists and geologists in their research. Proponents of the widely disputed
Younger Dryas impact hypothesis (YDIH) proposed that the abundant
charcoal, which is found in the Usselo Soil, and contemporaneous Lateglacial paleosols and organic sediments across Europe, may have been created by wildfires caused by a large bolide impact. This conclusion is based upon the reported occurrence of alleged extraterrestrial impact indicators and hypothetical correlations with
Clovis-age organic beds in North America. However, many geologists and geomorphologists wholly dispute the contemporaneous nature of the Usselo Soil with Clovis-age organic beds in North America, the presence of impact indicators within it, and the impact origin of the charcoal. The
YDIH has now been refuted comprehensively by earth scientists and planetary impact specialists. ==References==