Department of Geological and Atmospheric Sciences (GE-AT)

Stable Isotope Paleo Environments Research Group (SIPERG)

SIPERG Members


Dr. Alan Wanamaker- Principle Investigator: email-


Welcome to the SIPERG. I am a broadly trained geologist who is interested in using geochemical and sclerochronological techniques to document (and better understand) changes in Earth’s climate system. Although I mainly work in the northern North Atlantic Ocean within the most recent millennium, I am interested in other timescales and geographic regions. We have several exciting research projects that are underway, so if you would like to know more about us, and our research group, please contact me.

Suzanne Ankerstjerne- Lab Manager: email-


I am the lab manager for the Stable Isotope Laboratory in the geology department. My duties include coordinating and scheduling activities within the lab and maintaining the resources necessary to complete quality stable isotope measurements. I enjoy working with students, Iowa State faculty, and other scientists to obtain high quality data.


Mark Mathison: email-


I am a science enabler specializing in geological field work. My field areas have varied from dinosaurs in Mongolia to early hominids in East Africa. Current projects are Eocene primate sights in the Western Desert of Egypt and Glacial movement in Norway. My research interests are anything with geology and technology. I work for the Department of Geological and Atmospheric Sciences at Iowa State University as an IT and lab support person. Also, I help maintain the analytical equipment in the stable isotope lab and I assist in running our geology field camp in the Bighorn Mountains.


Madelyn Mette: email-

I am a PhD candidate at Iowa State.  My project involves using Arctica islandica shell-growth chronologies and annually resolved oxygen isotope records to reconstruct marine environmental variables in the arctic, specifically in response to the North Atlantic Oscillation/Arctic Oscillation across the northern hemisphere Medieval Warm Period/Little Ice Age/Modern Climate transitions.  I graduated from Macalester College in 2010 with a major in Geology major and a minor in Environmental Studies.


Diana Thatcher: email-

I am a MS student in my first year at Iowa State University working with Dr. Alan Wanamaker. I have my BS degree in meteorology from ISU with a minor in chemistry. My project involves studying speleothems from a cave in Portugal (behind me in this picture) to develop a decadal-scale paleoclimate record of hydroclimate and atmospheric variability during the late Holocene.


Undergraduate Research Assistants:

Andy Justin and Tyler Nicholson


Katie Luzier


Graduate Students

Erin Beirne: MS Geology 2011- "Pursuing a proxy for carbon cycling in the temperate North Atlantic: an investigation of the utility of Arctica islandica shell carbonate to millennial scale dissolved inorganic carbon reconstructions."

Shelly Griffin: MS Geology 2012- "Applying dendrochronology visual crossdating techniques to the marine bivalve Arctica islandica and assesing the utility of master growth chronologies as proxies for temperature and secondary productivity in the Gulf of Maine."

Erin Lower: MS Geology 2012- "A high-resolution geochemical proxy record of radiocarbon and oxygen isotopes in the Gulf of Maine using Arctica islandica shell Carbonate."


Undergraduate Researchers and Laboratory Assistants

Jessica Feenstra: Senior Capstone Project- "The use of nitrogen isotopes in freshwater mussels as an indicator of environmental change."

Ron VanDenBroeke

Megan Hosford

Andrew Lane

Dana Korneisel

Hayley Nelson

Shaina Ives