LSU Geologist Follows the Geologic Record of Possible Ancient Killer Fog Events

Dr. Huiming Bao and his students have been involved in a geological research project with some intriguing consequences. A strange oxygen isotope anomaly exists in sulfates extracted from ~28 million year old ash layers in outcrop at Scotts Bluff National Monument, Nebraska, and the surrounding Wildcat Ridge region. The current hypothesis leans toward a series of dry fog events, caused by volcanic eruptions far to the west. These eruptions could have emitted vast amounts of SO₂, which can convert to sulfate in the presence of ozone. If true, these “killer fog” events could have drastically altered the climatic and ecologic conditions in the region, and could happen again in the future.

Huiming Bao and his students gave talks to local communities while they were mapping in Nebraska panhandle. Local high-school students also assisted in collecting aerosol samples. To the right Katie Howell (MS-2006) explains the science and the meaning of the oxygen isotope data to a public audience in the Gering Civic Center (see article below).

The Star-Herald newspaper of Scotts Bluff/Gering, Nebraska reported the following on June 5, 2005: "Geologically speaking, Scotts Bluff National Monument is like nowhere else on earth.
    Because of its rarity Dr. Huiming Bao and graduate student Katie Howell will present a program at 7 pm, Tuesday June 7 at the Gering Convention Center about the very unusual ash layers in Scotts Bluff National Monument.
    Since the monument provides a snapshot of what nature can do, information gathered from research done this summer can make inferences about the past and better understand what could happen in the future."

Further reading:

Bao et. al, Sulfate oxygen-17 anomaly in an Oligocene ash bed in mid-North America: Was it the dry fogs?, Geophysical Research Letters, 30(16), 1-1-1-4, 2003.

Bao, Huiming, 2005, Sulfate in modern playa settings and in ash beds in hyperarid deserts: Implication on the origin of ¹⁷O-anomalous sulfate in an Oligocene ash bed. Chemical Geology, 214 (1-2), 127-134.