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Jim Mills - Metamorphic Geology in Bancroft, Canada

Research Description:

My research interests have focused on the origin of Precambrian pegmatitic veins of calcite in the Grenville Province of southeastern Ontario, Canada.  These calcite veins have been collected for over a hundred years due to the excellent specimens of apatite, biotite, edenite, titanite, and perthite that they contain.  The origin of these veins is enigmatic. Two hypotheses have been proposed over the years to explain their origin: 1) the injection of mantle-derived carbonatite magma, or 2) high-grade metamorphism and metasomatism of regional marble units during the Grenville orogeny 1.0 to 1.3 bya. My research over the last ten years has focused on defining the local and regional extent of the calcite veins through field mapping and GPS work, and analyzing the mineralogical, geochemical, and stable isotopic characteristics of these veins.

Recent Student-Faculty Research Projects:

Analysis of the geologic and geochemical relationship between calcite-vein dykes and granite plutons in the Bancroft Region, Ontario, Canada  (2011)

Student Collaborators: Ariana Borrello (GEO/SRF) & Brittany Slate (GEO)

Development of a web-based searchable GIS database: geology of the St. Francois Mountains, Missouri (2008)

Student Collaborators: Margaret Baber (GEO/SRF) & Alison Barnes (GEO/SRF)

Publications
Baber, M., Barnes, A., Mills, J.G., Jr., 2009, Development of a Google Earth geologic database: St. Francois Mountains, Missouri, Geological Society of America Abstracts with Programs, 41(4), p. 30.

GPS/GIS mapping and geochemical analyses of carbonatite dikes in the Bancroft Region, Ontario, Canada (2005)

Student Collaborators: Christopher Myrvold (GEO/SRF) & Samuel Rund (SRF)

Publications
Mills, J.G., Jr., Myrvold, C., Rund, S., and Melchiorre, E., 2005, Late Grenville metamorphic and shoshonite-related calcite-apatite vein formation near Essonville and Lake Clear, Ontario, Canada: Analogues for large-scale calcite-apatite vein-dyke formation in the Bancroft terrane of the Grenville Province?, Geological Society of America Abstracts with Programs, 37(7), p. 506.

Big Walnut Creek: a recharge study (2004)

Student Collaborators: S. Brett McArthur (SRF)

Publications
McArthur, S., Mills, J.G., Jr., and Melchiorre, E.,  2005, Flood-dominated recharge of a glaciofluvial aquifer, Big Walnut Creek, Greencastle, Indiana, Geological Society of America Abstracts with Programs, 37(7), p. 360.

Petrogenesis of calcite vein-dyke complexes, Ontario, Canada (2003)

Student Collaborators: Christopher Myrvold (GEO/SRF) & Kathryn Adank (GEO)

Publications
Mills, J.G., Jr., Adank, K., and Myrvold, C., 2003, Calcite Vein-dyke Complexes in the Bancroft, Ontario Region:  Evidence for a 930 Ma Carbonatitic Intrusive Event in Grenville Province, Ontario, Geological Society of America Abstracts with Programs, 35(6), p. 505.

Petrogenesis of the Bear Lake carbonatite, Ontario, Canada (2001)

Student Collaborators: Jennifer Berry (GEO)

Publications
Berry, J., and Mills, J.G., Jr., 2001, Evidence for the petrogenesis of a calcite vein-dyke complex, Bear Lake Diggings, Monmouth Township, Ontario, Canada, Geological Society of America Abstracts with Programs, 33(6), p. 373.

Other significant publications: 

Melchiorre, E., Dale, D., Mills, Jr., J.G., and Chapman, B., 2005, Geochemical and stable isotope evidence for precipitation and groundwater sourcing of acid mine drainage recharge at the Green Valley Site, Vigo County, Indiana, Mine Water and the Environment, 24, 88-100. (Chapman was a DePauw student.)

Melchiorre, E., Mills, J., Dale, D., and Chapman, B., 2005, A new occurrence of Xitieshanite (Fe3+(SO4)Cl · 6H2O) crystals in acid-mine seepways, Green Valley, Vigo County, Indiana, U.S.A., American Mineralogist, 90, 1518-1521. (Chapman was a DePauw student.)