NSF Org:	EAR Division Of Earth Sciences
Recipient:	VIRGINIA POLYTECHNIC INSTITUTE & STATE UNIVERSITY
Initial Amendment Date:	November 13, 2001
Latest Amendment Date:	January 14, 2005
Award Number:	0125918
Award Instrument:	Standard Grant
Program Manager:	Sonia Esperanca EAR  Division Of Earth Sciences GEO  Directorate for Geosciences
Start Date:	January 1, 2002
End Date:	December 31, 2005 (Estimated)
Total Intended Award Amount:	$336,500.00
Total Awarded Amount to Date:	$336,500.00
Funds Obligated to Date:	FY 2002 = $336,500.00
History of Investigator:	Robert Bodnar (Principal Investigator) rjb@vt.edu
Recipient Sponsored Research Office:	Virginia Polytechnic Institute and State University 300 TURNER ST NW BLACKSBURG VA  US  24060-3359 (540)231-5281
Sponsor Congressional District:	09
Primary Place of Performance:	Virginia Polytechnic Institute and State University 300 TURNER ST NW BLACKSBURG VA  US  24060-3359
Primary Place of Performance Congressional District:	09
Unique Entity Identifier (UEI):	QDE5UHE5XD16
Parent UEI:	X6KEFGLHSJX7
NSF Program(s):	Petrology and Geochemistry
Primary Program Source:	app-0102
Program Reference Code(s):	0000, OTHR
Program Element Code(s):	157300
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

Bodnar
EAR-0125918

A three-year experimental study will be conducted to determine the temperature-pressure-composition (PTX) limits of fluid immiscibility over the temperature and pressure range appropriate for magmatic-hydrothermal ore deposits associated with shallow granitic magmas. The study will focus on fluid compositions in aqueous solutions containing Na, K, Ca, and Fe chlorides, starting with the less-complex sub-systems containing Na-K, Na-Ca, and Na-Fe chlorides. Samples of immiscible fluids will be trapped in situ using the synthetic fluid inclusion technique, and compositions of the fluids will be determined using standard microthermometric analytical techniques. The compositional data will be used to develop an empirical numerical model to predict P-T conditions attending magmatic-hydrothermal processes. The model will require only information that is easily obtainable during conventional microthermometric and/or microchemical analysis of fluid inclusions.

The feasibility of the project has been documented by preliminary studies on the water-NaCl-KCl system. The data confirm that the synthetic fluid inclusions trap a representative sample of the fluid(s) present at experimental run conditions, and maintain these compositions during quenching to ambient laboratory conditions. Moreover, conventional microthermometric analysis of the coexisting liquid-rich and vapor-rich inclusions can be employed to determine the fluid compositions. Preliminary data for the water-NaCl-KCl system show that partitioning of sodium and potassium between coexisting liquid and vapor varies systematically with both temperature and pressure. Specifically, sodium partitioning into the liquid phase becomes less pronounced with increasing temperature and with decreasing pressure.

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