REFLECTIVE SPECTROSCOPY STUDY OF SELECTED SOILS FROM THE U.S. – MEXICO BORDER REGION IN TEXAS AND NEW MEXICO: PROVIDING CONTEXT FOR SEARCH AND RESCUE AND CRIMINAL INVESTIGATIONS

Hyperspectral remote sensing can be a powerful tool for large scale observations of border environments. The U.S. – Mexico border is an important political boundary with well-recognized human migration issues associated with it. Human trafficking, drug trafficking and weapons trafficking are common border activities that occur against the backdrop of soils. These activities therefore have the potential to disturb or use soils in various scenarios. Reflective spectra were collected from soil samples in New Mexico and Texas near border areas under both dry and wet conditions using an ASD FieldSpec 4. Bulk chemical data, scanning electron microscopy data, and powder X-ray diffraction data aid in the interpretation of reflective spectra. Absorption and topological features related to iron, silica content, and hydroxyls dominate most spectra, with lesser contributions from organic material and carbonate. Spectra of soils are largely distinct from items that are associated with human trafficking, drug trafficking and weapons trafficking, such as human blood, clothing, plastic, and metal from firearms. Results from this study provide some context for age estimation studies of items related to trafficking. Data can also be used to aid hyperspectral remote sensing efforts in locating and recovering persons in remote areas near the U.S. – Mexico border, such as migrants that are lost or in medical distress, lost hikers, and injured law enforcement personnel. Data can also be used for investigative purposes into acts of violence, especially when there may be situations involving areal denial, mass casualties, and mass graves. This study provides some framework for future studies of both the U.S. – Mexico border and other arid and semiarid settings where there is a high incidence of migration, violence, conflict, or illicit trade such as the Sahel.