b'AEM 2023Short abstractsframework of the regional fluid flow system. In 2022-23, threeflank, and along both the flanking rift zones that have sourced focus areas with proven lithium resources or considered highlylavas from fissure eruptions over the past two centuries. Work at prospective for lithium are being surveyed. Results from thisboth volcanoes is ongoing of merging AEM and MT data sets to effort can help to improve our understanding of the geologicimage these systems from the base of the crust to the surface.conditions and geophysical signatures associated with known resource regions and benefit future lithium resourceAirborne electromagnetic imaging for critical-minerals assessments by identifying regions with similar geophysical and geologic characteristics. resource assessmentPaul Bedrosian, Lyndsay Ball, Chloe Gustafson and Quantifying salinity in the layered coastal aquifersPatriciaMacQueenunderlying and adjacent to Delaware Bay USA using United States Geological Survey, Denver, COLORADO, United StatesAEM-derived resistivityMineral resource assessments are fundamentally grounded in Lyndsay Ball1, Burke Minsley1, Gavin Wilson1, Holly Michael2,dataspecifically data that differentiate regions prospective for Douglas Burns3, Mark Nardi4 and Emmanuel Charles5 a resource from those that are not. The Earth Mapping Resources 1. U.S. Geological Survey, Denver, CO, United States Initiative is collecting baseline geophysical data over targeted 2. University of Delaware, Newark, DE, USA areas of the United States to support upcoming critical mineral 3. U.S. Geological Survey, Troy, NY, USA assessments. Approximately 30 000 line-km per year of airborne 4. U.S. Geological Survey, Dover, DE, USA electromagnetic (AEM) data are being collected as part of this 5. U.S. Geological Survey, Lawrenceville, NJ, USA effort. In the first year, surveys in Nevada, Alabama and Alaska will be carried out to inform national-scale graphite and lithium Airborne electromagnetic (AEM) methods are particularly wellassessments. AEM surveying for graphite is one of the few cases suited to coastal aquifer salinity studies, yet the quantitativewhere geophysics can directly map the resource of interest; translation from bulk resistivity to fluid salinity carrieswe describe AEM surveys to be flown over two of the primary uncertainty that can impact mapped salinity distributionsgraphite resources in the nation. We also describe a regional and interpretations of the freshwater-saline interface andsurvey focused on lithium brines and clays, where AEM models hydrostratigraphic layers. A recent AEM survey of the regionwill be used to constrain deposit genesis models and to narrow near the Delaware Bay, USA highlights several challengesthe currently vast region considered prospective for lithium. We common to coastal hydrogeologic settings that may influencehighlight aspects of the survey design and show preliminary both qualitative and quantitative interpretation. We useresults for those surveys that have already begun flying.a Bayesian inversion to estimate geophysical parameter uncertainty, and results are integrated with hydrogeologicHelitem2System updates for broadband AEM datameasurements to develop quantitative interpretations of salinity across the freshwater-saline interface in stacked aquifers. Darren Burrows, David Murray and Graham KoniecznyInvestigating volcanic systems via multi-scaleXcalibur Multiphysics, Mississauga, ONTARIO, Canadaelectromagnetic imaging In the last five years, advances in receiver suspension and receiver construction have made airborne electromagnetic low-Paul A Bedrosian1, Carol A Finn1, Jade W Crosbie1, Dana E Peterson1,base frequency operation possible and greatly improved the James Kauahikaua2 and Patricia G Macqueen1 ability to explore in conductive environments. We discuss the 1. United States Geological Survey, Denver, COLORADO, United States changes made to the Xcalibur Helitem2, helicopter time domain 2. Hawaiian Volcano Observatory, United States Geological Survey,EM, system to enable low base frequency operation - first at 15 / Hilo, Hawaii, United States 12.5 Hz, and then at 7.5 / 6.25 Hz.Electromagnetic imaging provides a wealth of informationThe transmitter has also been redesigned to now use a square about the structure, composition, and processes withininput waveform at 50% duty cycle, with a rapid turn-off. At low volcanic systems. While deep-sensing techniques suchbase frequencies this results in a long, high powered transmitter as magnetotellurics (MT) focus on the magmatic system,pulse that still creates high frequency signal.airborne electromagnetics (AEM) is capable of mapping activeVarious data examples will be shown to illustrate the practical hydrothermal cells and their alteration products, faults, lavaadvantages of the system updates. This includes an example flows, water-saturated zones, and perched aquifers. All thesefrom Nevada where various Helitem2 system configurations components are important to improving volcanic hazardwere flown over a line of ground TDEM data at different heights, assessments and understanding magmatic and hydrothermalas well as a Nickel exploration project.processes at work beneath active volcanoes.We present two recent AEM studies at Yellowstone and KlaueaFree AEM data over NSW, Australiavolcanoes. At Yellowstone, AEM studies map conduits that connect heat and deep thermal fluids to surface thermalAstrid Carltonfeatures. We further identify a distinct electrical signature overDepartment of Regional NSW, Geological Survey of NSW, Maitland, hydrothermal domes which sheds light on their formationNSW, Australiaand potential for hydrothermal explosions. At Klauea, AEM models image the structural backbone of this complex volcano,The Geological Survey of New South Wales (GSNSW) in the including elevated conductivity over the summit lava lake,Department of Regional NSW, Mining Exploration & Geoscience, along faults accommodating collapse of the volcanos southhas an online application, called MinView, which allows 53 PREVIEW AUGUST 2023'