Comment Re:Yellowstone hotspot/McDonalds/Impact Crater (Score 1) 65
Three prominent closed gravity minima along the south edge of the study area may reveal underlying calderas, which are masked by younger Tertiary rocks. The largest possible caldera is about 10.52 by 15.5 mi (17 by 25 km) in size, and, if the assumed underlying tuffaceous sedimentary rocks are, on the average, 0.2 g/cm3 less dense than the surrounding volcanic rocks, the caldera extends to a depth of about 1.7 mi (2.7 km). The areas along the edges of the postulated calderas are considered sites for possible future mineral exploration.
and
In the southwestern part of the Range, gravity and magnetic anomalies of substantial size suggest the possible existence of a caldera or buried pluton. The widespread geochemical anomalies in this area are similar in size and magnitude to the mineralized McDermitt Caldera approximately 82 mi (132 km) to the northwest in the Opalite mining district. Whether a caldera or buried pluton is present in the area, the geochemical data suggest that area C shown on figure 2 has a possible potential for concealed mercury and complex precious metal sulfide deposits.
Also, the link to the McDonalds reference is: http://www.datapointed.net/201...