Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis

Pigati et al. 2012: 'impact markers' accumulate in ordinary wetlands

what the source states

Measurements in desert-wetland sequences of multiple ages found that candidate impact markers (including magnetic spherules) accumulate in such settings through ordinary processes, concentrated by the wetland environment, and concluded these materials and black mats are not uniquely diagnostic of an impact horizon.

what we infer

A background-rate result: the materials the hypothesis counts as event markers occur, and concentrate, without any event. Any boundary claim must therefore beat the wetland background — which returns the burden to sampling designs that measure background at all.

limitations

• Proponents dispute whether the wetland-accumulated materials are equivalent to their best boundary markers.