Bureau scientists Nels Iverson and Nelia Dunbar were co-authors on two papers published in early October that examine volcanic markers in the new South Pole Ice Core (SPICEcore) collected in Antarctica from 2014-2016.
A new Geosphere paper by Peter Lipman of the USGS and Matthew Zimmerer of the NM Bureau of Geology is now available online. The article discusses an enormous dike swarm that originates from the mid-Tertiary Platoro Caldera in southern CO. The dikes propagate southward from the caldera and are exposed up to 125 kilometers away in the San Juan basin of northern NM. The study has implications for regional magmatism and tectonics, as well as possible hazards at younger caldera systems.
This research, published on-line by Geosphere, describes the Laramide (Late Cretaceous to Eocene) fluvial evolution of the San Juan Basin of northwestern New Mexico. It focuses primarily on the Paleocene Nacimiento and Animas formations, using paleocurrent analysis and 40Ar/39Ar geochronology. The paper shows the Laramide fluvial evolution was complex and responded primarily to variations in subsidence rates within the basin.
The authors are Steve Cather (recently retired Bureau Field Geologist), Matt Heizler (Bureau geochronologist), and Tom Williamson (paleontologist at the New Mexico Museum of Natural History and Science).