Huckleberry Ridge Tuff

Huckleberry Ridge Tuff
Name	Huckleberry Ridge Tuff
Location	Yellowstone National Park/Wyoming/Idaho/Montana
Type	Ignimbrite
Age	~2.1 Ma
Volume	>2,500 km3
Eruption	Supereruption (Mallard Lake phase)
Coordinates	44.6°N 110.5°W

Contents

Huckleberry Ridge Tuff is a vast welded ignimbrite deposit produced by one of the largest known Quaternary supereruptions. The deposit is a key stratigraphic marker across Yellowstone National Park, Grand Teton National Park, Idaho, Montana, Wyoming, and adjacent provinces, and it is central to studies by institutions such as the United States Geological Survey, University of Utah, University of Wyoming, University of California, Berkeley, and the Smithsonian Institution.

Description and composition

The Huckleberry Ridge deposit is a densely welded, crystal-rich ash-flow tuff composed predominantly of high-silica rhyolite glass and phenocrysts of sanidine, quartz, plagioclase, biotite, and accessory zircon, magnetite, and apatite; these mineral assemblages are comparable to those characterized at Lava Creek Tuff, Mesa Falls Tuff, Bandelier Tuff, Toba Caldera, and Taupo Volcano. Petrographic descriptions have been published by researchers affiliated with Stanford University, University of Cambridge, Massachusetts Institute of Technology, Caltech, and University of Oxford. Geochemical fingerprints include high silica, elevated potassium and incompatible trace elements that parallel compositions reported for eruptions documented by GNS Science, Geological Survey of Canada, and the Geological Survey of Japan.

The eruption that produced the Huckleberry Ridge deposit corresponds to a supereruption with multiple eruption pulses, including the Mallard Lake phase, inferred from field correlations used by teams from Harvard University, Princeton University, Yale University, Columbia University, and Brown University. Stratigraphic work by Montana Bureau of Mines and Geology, Idaho Geological Survey, and Wyoming State Geological Survey indicates initial Plinian columns and widespread pyroclastic density currents, similar in dynamic to documented events at Mount St. Helens, Novarupta, Krakatoa, Mount Vesuvius, and Mount Pinatubo. Historical analogs and modern monitoring by National Oceanic and Atmospheric Administration, United States Geological Survey (USGS), University of Alaska Fairbanks, and Istituto Nazionale di Geofisica e Vulcanologia inform interpretations of emplacement processes, including welding, compaction, and gas escape.

The tuff covers an area extending from the Yellowstone Plateau into eastern Idaho and southern Montana, with outcrops mapped along transects used by expeditions from Smithsonian Institution, Royal Society, Geological Society of America, American Geophysical Union, and European Geosciences Union. Tephra correlations link distal ash layers with marine and lacustrine cores studied by researchers at Lamont–Doherty Earth Observatory, National Oceanography Centre, Scripps Institution of Oceanography, Alfred Wegener Institute, and GEOMAR Helmholtz Centre. The deposit’s areal distribution was reconstructed using data from boreholes sampled by Bureau of Reclamation, National Park Service, US Forest Service, Idaho National Laboratory, and US Army Corps of Engineers.

The eruption is tied to caldera-forming processes of the Yellowstone volcanic system and is temporally and spatially associated with caldera structures investigated by USGS Yellowstone Volcano Observatory, Yellowstone Center for Resources, Grand Canyon of the Yellowstone research teams, University of Utah Seismograph Stations, and National Park Service geologists. Comparisons have been made with caldera dynamics documented at Long Valley Caldera, Campi Flegrei, Aira Caldera, Taupo Volcanic Zone, and Santorini, while crustal magmatic studies involve collaborations with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Pacific Northwest National Laboratory, Oak Ridge National Laboratory, and Montana State University.

High-precision age constraints derive from 40Ar/39Ar incremental heating of sanidine and U-Pb zircon geochronology performed by teams at California Institute of Technology, Arizona State University, University of California, Santa Barbara, Carnegie Institution for Science, and GFZ German Research Centre for Geosciences. The widely cited age of ~2.1 million years places the eruption in the Early Pleistocene, with cross-checks against paleomagnetic stratigraphy studied at Paleomagnetism laboratories at University of Oxford and ETH Zurich and by correlation with marine isotope stages used by International Ocean Discovery Program investigators.

Detailed petrologic analyses describe phenocryst populations of sanidine, plagioclase, quartz, biotite, and rare hornblende, with trace zircon populations used for provenance and storage-time studies by research groups at University of Wisconsin–Madison, Pennsylvania State University, University of Minnesota, University of Michigan, and University of British Columbia. Mineral chemistry and melt inclusions have been examined using electron microprobe and SIMS facilities at Arizona State University, University of Tokyo, Max Planck Institute for Chemistry, National Institute of Geological Sciences (Philippines), and Czech Geological Survey. Experimental petrology from Carnegie Institution, ETH Zurich, Imperial College London, University of California, Davis, and University of Bristol has constrained pre-eruptive temperatures, pressures, and volatile contents, informing models of magma chamber processes originally proposed in comparative studies of Mount Mazama, Rinjani, Okmok, Mount Erebus, and Ijen.

Category:Volcanic tuffs