CAN SEDIMENT PROVENANCE ANALYSIS FINGERPRINT ILLICIT SAND SUPPLY NETWORKS?

Global demand for construction aggregates - mostly, sand and gravel - has exponentially increased throughout the developed and developing world over the last century and their production is projected to grow from 35 Gt/year in 2011 to 82 Gt/year in 2060. Regionals shortages of reserves of the appropriate quality due to overexploitation or increasing socioecological constraints and an increasing awareness of the environmental impacts of indiscriminate sand mining has generated a scenario in which demand continues to go up yet responsibly sourced supply is increasingly difficult to come by, particularly in fast developing regions. This scenario has led to the emergence in certain areas of sophisticated illicit supply networks of sand. The societal and environmental implications of the local development of these illicit networks have cascading negative externalities yet the networks are inherently difficult to regulate and track. Single grain detrital provenance analysis may offer an avenue to provide a fingerprint for illicitly derived sand that relies on the composition of the sediment itself without having to directly observe the supply chain. Sedimentology studies of modern rivers across many locations globally show that single grain provenance techniques can discern sediment derived from different individual rivers and streams even at a local scale. Where illicit sand mining occurs in geologically complex regions, such as south and southeast Asia (among others), these techniques should be able to fingerprint the anthropogenic extraction and dispersal of mined sediment in the same way sedimentologist fingerprint natural sediment dispersal patterns. We present here an outline of a series of potential case studies from Asia in which local geology and sediment composition suggest that illicitly derived sediment should have a distinct signature that could be used to track its extraction and trade. Such techniques could in the future assist local authorities in regulating the extraction of this valuable natural resource.