 The last speaker is Mark from New Mexico Institute of Mining and Technology. OK, I'm going to change topics a little bit and talk about really some exciting emerging studies that are being done using magnetotellurics, both in continental venues and also in marine venues, combined with mathematical modeling, to reveal new groundwater resources that have yet to be developed in some of these cases. So the first is looking at offshore groundwater, fresh offshore groundwater. In the continental shelves, it's a global phenomenon. Why is it there? Well, on average, over the last 2 million years, sea level was 40 meters lower than present. And just 21,000 years ago, sea level was 120 meters below its current elevation. And the shoreline was much further off, exposing vast quantities of the continental shelf to meteoric recharge. There's also onshore connections to aquifer systems that crop the aquifers crop out on shore. And the gradients are higher during these sea level low stands. As I said, it's a global phenomenon. This is a paper by Vincent Post and our group that tried to quantify the volumes of offshore freshwater. Within 50 kilometers of the shoreline, we estimate that there's 10 to the fifth cubic kilometers of freshwater. Globally, we've also tried to test. There's only a few sites where there's actually well data. And those estimates were based on essentially six cross sections where we could put together salinity contour maps. We've also developed models of the New England area and confirmed that between 1 and 10 cubic kilometers per lateral distance of the shoreline per kilometer shoreline, this freshwater exists. What's truly exciting is that now marine magnetotelurics are being used. This was developed to explore for oil, but is now being used to look for freshwater. This is a great study just out two weeks ago by Chloe Gustafson, Kerry Key, and Rob Evans at La Montdority and Woods Hole. The map on the right show empty images of freshwater. That's the yellow patterns. Resistive formation resistivities can be imaged on the offshore. In two sites, they looked at Martha's Vineyard in New Jersey and they deployed both marine magnetoteluric systems on the sea floor. And then they had a controlled source electromagnetic system that was towed behind a boat and they did joint inversions. But it's amazing. This is really, I think, transformative that we'll be able to map offshore freshwater. I'd like to switch topics to using MT to look at deep crystal embasement groundwater flow systems in the arid southwest. Companies, agribusinesses have been using this hot water and fresh water to grow tilapia, to heat greenhouses and actually use the water in greenhouses. New Mexico is blessed with permeable crystalline rocks and high heat flow. One specific study that we've been working on is looking at the plumbing of deep groundwater flow in the crystalline basement below the truth or consequences town. It was formerly called Hot Springs, New Mexico. There's about 12 spas. The salinity of this geothermal water that's coming right out of the crystalline basement is 42 degrees. Well, it's 1,900 milligrams per liter, 42 degrees sea. It has carbon 14 age dates of 6,000 to 11,000 years old. And we believe it's coming from deep recharge in the mountainous terrains about 60 kilometers away. But the temperatures are quite warm and shallow. CV TICE estimated that back in the 40s that the geothermal discharge was 2 million gallons per day. We estimate that's about 10% of the mountain front recharge is actually discharging through a hydrologic window where the crystalline basement is exposed essentially at the land surface. There are no confining units to block the discharge coming to the surface. The recharge rates for this mountainous terrains are probably 5 centimeters to 10 centimeters a year. This is a nice study of recharge by Fred Philip and Dan Cadall's group. We've developed this conceptual model of deep groundwater flow. We've convinced ourselves through numerical modeling that it has to be a very deep 10 kilometer deep flow system, probably with the crystalline basement permeabilities that are unheard of, 10 to the negative 12 meters squared. We conducted an empty study of this region from the recharge to the discharge area. Jeff Peppin, my grad student, led the charge on that. And here's the amazing results that in the recharge areas up in the mountains of Alamosa Creek and Chachionegro, you can see more resistive crystalline basement rocks in the recharge area around 100 o meters to 200 o meters. That's quite a bit more permeable or more conductive than typical crystalline basin rock, which is 1,000 to 10,000 o meters. But in the discharge area down by the Hot Springs districts, we see as these geothermal fluids pick up heat and salinity along the flow path, they become more conductive. And you can image the upflow zone down to 10 kilometers. And you cannot produce the thermal anomalies or the salinity without this deep flow system. You might question, well, how can you have a Darcy permeability at 10 kilometers? Well, Jim Butler helped us analyze a pumping test in the shallow crystalline basement within the Hot Springs District at TRC. And we got permeabilities. We saw inertial effects within the pump test and a permeability of three times 10 to the negative 10th meter squared. I'd just like to point out that these deep-seated crystalline basement flow systems are economically important to the local communities in the air at Southwest. In Wilcox, Arizona, there's a geothermal greenhouse that's been drilled into vitro. There's a geothermal well in vitrified tufts at about a kilometer depth that's producing over 1,000 gallons per minute and 80 degrees C water. They're using the water to grow tomatoes. There's also this amazing aquaculture facility in Lordsburg, New Mexico. These are deep flow systems with no local recharge. So I'd just like to conclude by saying that there are huge volumes of offshore freshwater are sequestered in continental shelf sands. This is a new resource potentially available to coastal mega cities. Crystalline basement and volcanic formations represent a viable resource. And for arid Southwestern communities, I call it the ultimate food, water, and energy nexus. These greenhouse operations pay for themselves. They don't need government money. They essentially have free heat and sustainable water. And I think an exciting thing to think about in the future is using magnetotoleric surveys in an Earthscope style campaign to look at deep flow systems and deep unconventional aquifers in the US and continental shelf things.