Research Project

Wonoka Fm (light-colored) in three parts of a submarine paleocanyon.

Within our planet's 4.5 billion year old history, the period between 635 to 542 Ma—the Ediacaran—witnessed the most depleted C¹³/C¹² ratio observed in all of Earth history. This anomaly, dubbed the Shuram excursion after the formation in which it was originally discovered, is recorded within carbonate rocks around the globe in locations such as Oman, South China, Namibia, and indeed--South Australia.  Assuming that these carbonates hold a true record of the carbon isotope signatures of the oceans they formed in, this find suggests a major disturbance in the global carbon cycle.  Additionally, the anomaly immediately precedes the rise and evolution of macroscopic multicellular animals in tandem with oxygenation of the deep ocean, however the relationship between these events remains speculative due to the uncertainty of their relative timing.

In South Australia, the limestone preserving the unique carbon isotopic signature of the Shuram anomaly—the Wonoka Formation—has a thickness varying between 400 and 1500 meters.   This summer, Jon and I will be exploring the northern Flinders Ranges, where the bottom of the Wonoka is marked by 1000 meter-deep submarine paleocanyons.  Through detailed mapping of geologic units and methodological sampling of canyon carbonate rock, we can place the Shuram anomaly in a better physical stratigraphic context in hopes of further constraining its timing.

The Shuram anomaly is the main focus of Jon's research for his Ph.D.; I am merely working as his research and field assistant this summer.  However, I am planning on conducting some independent research of my own on an offshoot project that will contribute to Jon's research—hopefully I'll be able to write about it all for my fall junior paper!