2002-2003 Science Planning Summary

Geology & Geophysics

Dr. Scott Borg
Program Manager

GO-056-O

NSF/OPP 98-14332
Station: McMurdo Station
RPSC POC: Kirk Salveson
Research Site(s): Dry Valleys

The ferrar magmatic mush column system, Dry Valleys, Antarctica
Dr. Bruce D. Marsh
Johns Hopkins University
Morton K. Blaustein Department of Earth and Planetary Sciences
bmarsh@jhu.edu
http://www.jhu.edu/~eps/faculty/marsh/index.html

Deploying Team Members: Amanda D Charrier . Sarah J Fowler . Taber G Hersum . Bruce D Marsh . Michael Weiss . Karina Zavala
Research Objectives: Over billions of years the Earth's geologic processes have produced a wide diversity of rock types that have given rise to the fundamental surface features: Continents and ocean basins. The details of these physical and chemical processes remain largely undiscovered. Although present day volcanism exemplifies the general process of differentiation through the variety of lava expelled, it is not clear how volcanic eruptions relate to the prolonged, detailed magmatic processes that are responsible for the final result. Solidified bodies of magma (called plutons), once deeply buried and now exposed through erosion, furnish some evidence, but often the spatial context of these plutons within the magmatic-volcanic system is not clear. By studying a group of magmatic rocks displaying these processes, researchers hope to help solve this fundamental question. These rocks, which expose the fundamental relationship of plutonism to volcanism, may be an important key to understanding planetary magmatism in the most general terms.

The Ferrar magmatic system in the McMurdo Dry Valleys (Ferrar-DV) exemplifies the emerging global paradigm of a stack of magmatic sheets or sills connected below to a deep-seated magmatic source and above to a volcanic center. The world's major magmatic systems tend to exhibit this same style, but only the Ferrar-DV clearly reveals the critical physical and chemical connections between the deep, mush-dominated system and near-surface, pre-eruptive sill system.

The objective of this project is to ascertain the full physical and chemical nature of the Ferrar-DV magmatic system. The major goals are:

-To delineate its vertical and horizontal extent

-To understand the dynamics of its establishment

-To understand the mechanics of formation of the Dais layered intrusion

-To produce a map of Ferrar rocks throughout the Dry Valleys

-To produce a 3-D model of the orthopyroxene tongue and feeder system. Researchers will also attempt to elucidate a rarely seen transition between plutonic and volcanic systems, which may have implications fundamental to planetary magmatism.


Field Season Overview:
Team members will travel by helicopter from McMurdo Station to Bull Pass and establish a base camp from which the fieldwork will be staged. Researchers will then travel by helicopter to scout suitable locations for groundwork and take aerial photographs. From the selected locations, they will travel on foot, mapping locations of rocks and collecting samples throughout the magmatic bodies with the goal of fully characterizing them in terms of chemical properties and crystal content.

The researchers will return to McMurdo Station by where they will prepare the rock samples for return to the home institution.