Sarah Carmichael, Department of Geology - Appalachian State University

My interests involve reactive fluid flow in all levels of the earth's crust, in both ancient and modern environments - through regional and contact metamorphism, metasomatism at mid-ocean ridges, and through weathering reactions during mining operations.

As fluids travel through permeable pathways in rocks, they change the surrounding mineralogy, leaving a record of their interaction. In turn, the chemistry of these fluids changes according to the duration of reaction. I apply the concepts of equilibrium thermodynamics and mass transport to these reactive fluid flow systems in order to more fully understand fluid-rock interactions under a variety of environmental conditions.

I use scanning electron microscopy, scanned cathodoluminescence microscopy, laser-ablation inductively coupled plasma optical emission spectroscopy (LA-ICP-OES), and oxygen and carbon stable isotope analysis to trace the fluid pathways in rocks, and ICP-MS, ICP-OES and flame atomic absorption to characterize the fluids present in modern water-rock systems.

If you are interested in working with me, please contact me with your research interests, and see my Undergraduate Research Contract.

I am starting new work in the southern Appalachians, investigating the amygdaloidal Unicoi basalt in eastern Tennessee and southwestern Virginia. Cross-cutting relationships between the veins indicate different generations of fluid flow, with different chemistries. The timing of these fluid flow events has not yet been constrained, but was likely related to rifting events during the early Cambrian or hydrothermal flow through faults during the Taconic Orogeny.

Prior to coming to Appalachian State, I spent much of my time at sea, on the R/V Atlantis, studying hydrothermal vents located at spreading ridges on the seafloor. My current research explores fluid-rock interactions in altered basalt at the 9°50'N East Pacific Rise (EPR) Integrated Study Site (ISS). These rocks are unique for several reasons: they are the only samples to date that have been collected from a stockwork beneath an active hydrothermal vent, they have 15 years of hydrothermal vent fluid data associated with them, and they represent an active hydrothermal upflow zone.

I am characterizing the trace element fluid compositions from the associated hydrothermal vent, characterizing the solid phases (using a combination of electron microscopy, cathodoluminescence, and LA-ICPMS), and will be modeling the geochemistry of the system using a combination of the EQ3/6 code (Wolery, 1992) and reactive transport theory.
anhydrite surrounded by sulfides

cathodoluminescence image showing trace element
zoning in anhydrite, 9°50'N EPR

getting into the Alvin
Alvin dive, East Pacific Rise, 2006

Click the links below for more information about:

9°50'N East Pacific Rise (EPR) Integrated Study Site (ISS)

deep sea hydrothermal vents

The National Deep Submergence Facility

DSV Alvin

R/V Atlantis

My graduate work in the Latemar carbonate buildup, northern Italy explores the "Dolomite Problem," a classic sedimentology problem, from a metamorphic petrologist's point of view. It uses reactive transport theory to interpret the chemical, isotopic, and mineralogic effects of fluid-rock reactions in a (very) low-temperature metamorphic setting.

Latemar carbonate buildup, northern Italy

Recent Publications and Abstracts

Carmichael, Sarah K., Ferry, John M., and McDonough, William F., 2008 (in press, American Journal of Science), Formation of replacement dolomite by infiltration of diffuse effluent: Latemar carbonate buildup, Dolomites, northern Italy (Part I).

Carmichael, Sarah K., and Ferry, John M., 2008 (in press, American Journal of Science), Formation of replacement dolomite by infiltration of diffuse effluent: Latemar carbonate buildup, Dolomites, northern Italy (Part II).

Carmichael, Sarah K., and Von Damm, Karen L., 2008, (in press, Geochimica et Cosmochimica Acta - abstract volume), Constraining reactions between MOR vent fluids and new oceanic crust: the hydrothermal upflow zone beneath M vent, 9°50'N EPR.

Klein, E. M., White, S., Perfit, M., von Damm, K., Fornari, D., Soule, A., Ridley, I., Carmichael, S., Sims, K., Wanless, D., Zaino, A., Fundis, A., Mason, J., O'Brien, J., Waters, C., Mansfield, F., Neely, K., Laliberte, J., Goehring, E., Preston, L., 2007, Detailed investigation of the overlapping spreading center and 9 degrees north on the East Pacific Rise: overview of the Medusa 2007 cruise activities. AGU, 88(52), Fall Meet. Suppl., Abstract T32B-03.

Von Damm, K., Bates, M., Carmichael, S., Meana-Prado, F., and McDermott, J., Response of the 9-10N EPR Hydrothermal Systems to Recent Volcanic Eruptions, AGU, 87(52), Fall Meet. Suppl., Abstract V13C-02.

Carmichael, Sarah K., and Ferry, John M., 2005, Dolomitization of a Triassic atoll in a novel seafloor fluid flow system by reaction of limestone with diffuse effluent: Latemar carbonate buildup, Dolomites, northern Italy. Geological Society of America, Abstracts with Programs, v. 37, no. 7, p. 536.

Carmichael, Sarah K., and Ferry, John M., 2005, The origin of replacement dolomite, Dolomites, northern Italy: Part 1. Geochimica et Cosmochimica Acta, vol. 69, no. 10S, p. A785.

Ferry, John M., and Carmichael, Sarah K., 2005, The origin of replacement dolomite, Dolomites, northern Italy: Part 2. Geochimica et Cosmochimica Acta, vol. 69, no. 10S, p. A786.

Brady, John B., Mohlman, Heidi K., Harris, Caroline, Carmichael, Sarah K., Jacob, Lisa J., and Chaparro, Wilfredo R., 2004, General geology and geochemistry of metamorphosed Proterozoic mafic dikes and sills, Tobacco Root Mountains, Montana. In Brady, John B., Burger, H. Robert, Cheney, John T., and Harms, Tekla A., eds., Precambrian geology of the Tobacco Root Mountains, Montana. Geological Society of America Special Paper 377, p. 89-104.

	2008-		Assistant Professor, Appalachian State University
	2007-2008		Visiting Assistant Professor, Appalachian State University
	2006-2007		Postdoctoral Research Associate, University of New Hampshire
	2006		Ph.D., Earth and Planetary Sciences, Johns Hopkins University
	2002		M.A., Earth and Planetary Sciences, Johns Hopkins University
	1998-2000		Project Hydrogeologist, GeoTrans, Inc., Harvard, MA
	1998		B.A., Geology with Highest Honors, Smith College
	Curriculum Vitae

Sarah Carmichael

Academic Background and Professional Experience

Teaching

Research Interests

Recent Publications and Abstracts

I am starting new work in the southern Appalachians, investigating the amygdaloidal Unicoi basalt in eastern Tennessee and southwestern Virginia. Cross-cutting relationships between the veins indicate different generations of fluid flow, with different chemistries. The timing of these fluid flow events has not yet been constrained, but was likely related to rifting events during the early Cambrian or hydrothermal flow through faults during the Taconic Orogeny.
Prior to coming to Appalachian State, I spent much of my time at sea, on the R/V Atlantis, studying hydrothermal vents located at spreading ridges on the seafloor. My current research explores fluid-rock interactions in altered basalt at the 9°50'N East Pacific Rise (EPR) Integrated Study Site (ISS). These rocks are unique for several reasons: they are the only samples to date that have been collected from a stockwork beneath an active hydrothermal vent, they have 15 years of hydrothermal vent fluid data associated with them, and they represent an active hydrothermal upflow zone. I am characterizing the trace element fluid compositions from the associated hydrothermal vent, characterizing the solid phases (using a combination of electron microscopy, cathodoluminescence, and LA-ICPMS), and will be modeling the geochemistry of the system using a combination of the EQ3/6 code (Wolery, 1992) and reactive transport theory.		cathodoluminescence image showing trace element zoning in anhydrite, 9°50'N EPR
Alvin dive, East Pacific Rise, 2006	Click the links below for more information about: 9°50'N East Pacific Rise (EPR) Integrated Study Site (ISS) deep sea hydrothermal vents The National Deep Submergence Facility DSV Alvin R/V Atlantis
My graduate work in the Latemar carbonate buildup, northern Italy explores the "Dolomite Problem," a classic sedimentology problem, from a metamorphic petrologist's point of view. It uses reactive transport theory to interpret the chemical, isotopic, and mineralogic effects of fluid-rock reactions in a (very) low-temperature metamorphic setting.		Latemar carbonate buildup, northern Italy