Glacial-Marine Sedimentology at UF

(not an oxymoron…)

Glacial Erosion and the Creation of High-Latitude Continental Margins

Glacial erosion is a principal issue in contemporary research on high-latitude marine sedimentation and landscape evolution. The modes of transfer of glaciogenic sediments and the spatio-temporal variation in transfer rates are critical to improve understanding the global increase in sedimentation beginning ~2-4 Myr ago that coincided with a change to a cooler and more variable climate, and the onset of late Cenozoic glaciation and in deciphering the architecture of the massive (up to 5 km-thick) late Tertiary and Quaternary sedimentary sequence in the Barents Sea and off Scandinavia. These thick deposits contain a rich history of climate change recorded in both proxy climate data (e.g., ice-rafted debris [IRD], fossil foraminifera) and sediment accumulation rates that, in part, reflect climate-driven glacial sediment yields.

Over the past half decade, I have been examining the fate of glacially derived sediments in the coastal and marine environment in Southern Alaska. Estimated sediment yields for the glaciers along southern Alaska are the highest in the world, and I’m trying to determine what particular characteristics of glaciers in southern Alaska cause the high sediment yields and to ascertain whether the sediment output from glaciers show important temporal variations related to glacier dynamics or climate changes.

To accomplish these studies, I’ve used sedimentological and radioisotopic measurements coupled with the latest techniques in image analyses of x-radiographs and time series analyses to evaluate the sediment record for evidence of the timing and magnitude of glacial processes. To evaluate longer Holocene time scales, I’ve been collaborating with John Milliman at the Virginia Institute of Marine Sciences using seismic reflection profiles to assess glacial erosion rates. The following publications have resulted from these studies:

J.M. Jaeger and J.D. Milliman, The Holocene Marine Record of Glacial Erosion from the Chugach-St. Elias Mountains, South-Central Alaska, Quaternary Research, in prep.

J.M. Jaeger, Developing High-Resolution Chronologies in Glacimarine Sediments: Examples From Southeastern Alaska. Geological Society Special Publication, in press. [pdf preprint]

J.M. Jaeger, B. Hallet, T. Pavlis, J. Sauber, D. Lawson, J. Milliman, R. Powell, S.P. Anderson, R. Anderson, 2001. Orogenic and glacial research in pristine southern Alaska. Eos, Transactions, American Geophysical Union, Vol. 82 (19), p. 213-216.

Ding, X., S.M. Henrichs and J.M. Jaeger. Spatial and Temporal Variations of Sedimentary Organic Matter on the Shelf and Slope of the Northeastern Gulf of Alaska. Continental Shelf Research, in revision.

J.M. Jaeger, and C.A. Nittrouer, The formation of sedimentary lithofacies on the Gulf of Alaska continental shelf. Continental Shelf Research, accepted.

J.M. Jaeger, and C.A. Nittrouer, 1999, Marine record of surge-induced outburst floods from the Bering Glacier, Alaska. Geology, 27 (9), 847-850.

J.M. Jaeger, and C.A. Nittrouer, 1999. Sediment deposition in an Alaskan fjord: Controls on the formation and preservation of sedimentary structures in Icy Bay. Journal of Sedimentary Research, 69, 1011-1026.

J.M. Jaeger, and C.A. Nittrouer, 1998. Sediment accumulation along a glacially impacted mountainous coastline: Northeast Gulf of Alaska. Basin Research, 10:155-175.

What’s Next??

Along with geomorphologists at the Quaternary Research Center at the University of Washington, we have proposed a multi-year interdisciplinary study to examine the role of glacier dynamics in determining glacial sediment yields of three tidewater glaciers in Icy Bay Alaska through a novel and powerful combination of techniques and resources from glaciology and marine science. To better develop the analytical techniques necessary measure temporal variations in sediment yield from these glaciers, I am looking for a graduate student to expand on the techniques developed in the Geologic Society manuscript (see above) using previously collected cores from Icy Bay and from new cores I hope to collect in the summer of 2002 from proglacial lakes of the Bering Glacier.

For additional information on the region, see:

Glacial Erosion in Southern Alaska, a MARGINS Allied Field Area