Prof. Robert Gaines Receives $184,036 NSF Grant for Project Investigating Origins of Complex Life
Associate Professor of Geology Robert Gaines has received a $184,036 National Science Foundation grant for “The Chengjiang Scientific Drilling Project and an Integrated Model for Understanding Burgess Shale-type deposits.” The deposits are famous for their exceptional preservation of soft-bodied fossils of the Cambrian era, during the dawn of animal life.
The Chengjiang shale is located in Yunnan Province, in southwest China, bordering Vietnam, Myanmar and Tibet, at the transition between the jungle and the high plateau. The current drilling site is at 6,500 feet, and the research team plans to expand drilling along a shallow to deep water transect in the ancient marine layers that were uplifted during the building of the Himalayan mountains.
In these types of deposits, eyes, guts, gills and other soft tissues are preserved in remarkable detail. “How these fossils came to be preserved is not only a 100-year-old curiosity,” says Gaines, “but is critical to understanding the evolving chemistry of the earth’s surface, which is directly relevant for the evolution of animals from single-celled organisms.
“The Cambrian explosion is a singular event in life’s history when almost all animal phyla appear on earth rather than gradually as Darwin would have predicted,” he explains, “To many of us, this implies some kind of spark in the Earth’s systems which triggered the event. Essentially, the biological machinery was in place to make animals but the conditions were not yet permissible for their evolution.”
The Chengjiang area has been known since 1984 to have exquisitely preserved Burgess shale-type fossils of the earliest animals. This is the first scientific drilling examining the Chengjiang deposits in a systematic way. Unlike other Burgess Shale sites where Gaines does fieldwork, drilling is necessary at this site because the Indian monsoon rains leach certain minerals from the rocks when they are exposed on the surface. The geochemical information contained within these minerals provide important proxies to understanding environmental conditions of the Cambrian Earth.
The team has already drilled two sites in Yunnan, in a process that takes four-to-five weeks, in a 24-hour a day operation, to reach depths greater than 200 meters (>650 feet). Core samples are extracted every two-to-four hours. The continuous core sample, which measures 12 cm in diameter and 200+ meters long, is sent to a laboratory at Yunnan University where Gaines and colleagues spend three weeks describing it in millimeter-scale detail and taking hundreds of samples. Additional analysis is done at Pomona College, the Nordic Center for Earth Evolution at the University of Southern Denmark and Yunnan University.
On the Pomona campus, the analysis will be aided by a new CHNS (carbon, hydrogen, nitrogen, sulfur) elemental analyzer, whose purchase was funded by Pomona College and the NSF grant. The state-of-the-art machine measures the lightest elements in the periodic table, and with Pomona’s X-ray flouresence analyzer, will give Pomona researchers, both faculty and students, the ability to measure the full-range of the periodic table.
This summer, Gaines will return to China to select the 2012 drilling site along the transect from ancient shallow-water environments to ancient deep-water environments. This third core, to be drilled in strata that were deposited in deep water, is especially important because these waters had a better connection to the open ocean. Analysis of this deposited material will allow the team to tease out the influence of local ocean chemistry from the global signal of the evolving chemistry of Earth’s oceans and atmosphere during this critical interval in the history of life.
According to Gaines, “Our preliminary analysis of the Chengjiang samples and those from similar sites around the world seems to indicate that increasing oxygen levels and high oceanic alkalinity may be keys to early animal evolution and both are involved in the unique preservation that we find at Chengjiang.”
Gaines is the principal investigator for the NSF grant. His collaborators on the project are Hou Xianguang and Qi Changshi, of Yunnan University; Emma Hammarlund and Don Canfield of the Nordic Center for Earth Evolution, University of Southern Denmark; and Mr. Wu, Mr. Huang and Mr. Yang of the Kunming Luyi Mining Company.