Environmental magnetism is a powerful method for dating, globally correlating, and understanding natural and/or anthropogenic impacts on sedimentary systems.
Environmental magnetism is comprised of both paleomagnetism and rock-magnetism.
Paleomagnetism is the study of the direction and intensity of the Earth’s magnetic field as recorded in sediment and rocks. Paleomagnetism is a powerful tool for dating and global correlation of sedimentary sequences.
Rock-magnetism is the study of the concentration, grain-size, and mineralogy of the magnetic fraction of natural samples. Rock-magnetism has been used successfully in a wide range of depositional environments to understand past climate change and/or anthropogenic impacts on depositional systems.
Climatic, limnologic, and anthropogenic processes affect many aspects of depositional systems including; sediment sources, sediment transport paths, sediment influx rates, lake productivity, weathering/pedogenic phases and reduction diagensis. These components, in turn, influence the type of sediment accumulating in the lake and therefore the magnetic properties of the sediment.
By measuring downcore rock-magnetic profiles it is possible to document variations in climatic, limnologic and anthropogenic forcing over time.
Dr. John Peck applies an interdisciplinary approach to the study of sedimentary environments, including the use of environmental magnetism, to address questions about natural and anthropogenic change and to date sediment deposits. Ongoing studies of Quaternary paleolimnology and paleoclimatology use environmental magnetic methods to study sediment sequences from Asia, Africa, and Ohio.
ASIA
Dr. Peck completed five trips to Lake Baikal, Russia to study sediment drill cores spanning the last 11 Ma. He has completed three field trips to collect sediment cores from Mongolian lakes. The sediment from Mongolian lakes and their watersheds preserve high-resolution Holocene paleoclimatic records that reveal dramatic changes in moisture supply in central Asia.
A major focus of my research is to provide new paleoclimatic records from the continental interior of central Asia (Lake Baikal; Mongolian lakes).
AFRICADr. Peck also obtained sediment cores from Lake Bosumtwi, Ghana that will provide new insights on West African climate change. He is also working with a large group planning to drill this 1 Ma old impact crater lake.
Ryan will examine the environmental magnetic record from Bosumtwi as a potential measure of eolian dust flux to the lake. The goal is to construct a proxy record of aridity in the Sahel source area of the dust.
The Department of Geology is well equipped to obtain high-quality sediment samples from a variety of depositional environments including lakes, coastal ocean, caves, and glacial deposits.
