Hyperspectral Remote Sensing Data and a Multi-proxy Investigation for Characterizing Mineral Resource Deposits in Alaska
Alaska is considered one of the premier locations in the world for mineral exploration and for discovery of world-class mineral resources. However, Alaska is one of the most sparsely mapped regions of the world and extensive ongoing efforts are underway to discover areas for potential development. In Alaska, both geologic mapping and minerals exploration are challenging for the same reasons: the state’s large size, limited transportation infrastructure, harsh climate, steep terrain, and an extensive cover of dense vegetation in the lower altitudes and snow and glaciers at the higher elevations. New strategies aimed at overcoming these obstacles are needed if Alaska’s mineral endowment is to be properly evaluated. This project will use remotely sensed imaging spectroscopy data in a region of known mineralization and relief as a mineral resource assessment tool. Project objectives are to define the geologic and topographic parameters reflected in the acquired data and to gather information on the extent and type of vegetative cover. The synthesis of results from this investigation will be used to enhance geologic mapping and to develop a predictive exploration model for the identification of precious metal and critical mineral deposits that can be used in Alaska and replicated in other parts of the world.
This work will provide the framework for determining the relationship of an area’s surface materials with its underlying geology. Geologic mapping, ground geochemistry, geobotany, geophysics, and multiple types of remotely sensed data will be used to define potential zones of mineralization based on host rock lithology, surface chemistry, weathering products, and zonation patterns. In heavily vegetated areas, links between the underlying lithogeochemistry and the spectral characteristics of associated vegetation types will be established. Data collection will be focused on areas of mutual interest beneficial to on-going USGS investigations.
The USGS will partner with the State of Alaska, other Department of Interior agencies, contracting officials, contractors, and other interested parties in order to complete this large-scale data acquisition project. Data for known zones of mineralization will serve as test and validation sites for new mapping algorithms, and data collection protocols for new targets will be prioritized based on the known or expected deposit type, size of the target and accessibility from home base, weather patterns, and the likelihood of a successful outcome. Priorities will include both primary and secondary targets and will take into consideration the interests of collaborators.
Data Integration and Synthesis
By using a zone of known mineralization to establish how remote sensing data reflects the links between surface and underlying materials, researchers integrate geology, geochemistry, geophysics, and botany of a region to form a cohesive picture of the area’s geologic system and associated environmental footprint. Markers from this system can then be compared to other areas to determine if significant mineralization is present. Geological, geochemical, geophysical, and derivative maps will be developed for each deposit studied.