Data from temperature measurements in research drill hole Y-7, Upper Geyser Basin, Yellowstone National Park

Active thermal areas in Yellowstone National Park provide insight into a variety of hydrothermal processes occurring at depth, such as water-rock interactions, the formation of alteration minerals, and microbial (thermophile) metabolism in extreme environments. Research drill hole Y-7 (44°29'8.74", -110°51'7.67") is one of 13 holes completed by the U.S. Geological Survey in 1967 and 1968 at selected sites in hot spring and geyser areas of the park (White and others, 1975). The holes were drilled with a goal of obtaining physical and chemical data on the shallow part of the hydrothermal system. Drill hole Y-7 is located at the northern end of the Biscuit Basin parking lot, in the northern part of the Upper Geyser Basin. Drilling of Y-7 in September 1967 started from an elevation of ~2,529 meters and reaching a total depth of 74 meters. A temperature of 143.1 °C was measured at a depth of 82 meters a week after drilling was completed, and a temperature of 141.6 °C was measured in September 1973 (White et al., 1975).
 
Following drilling, a 4-inch (10 centimeters) casing was installed to a depth of 7 meters and 3-inch (8 centimeters) casing was installed to a depth of 35 meters. In subsequent years, studies of hydrothermal alteration chemistry and mineralogy in core samples from drill hole Y-7 were conducted (Keith et al., 1978; Sturchio et al., 1986). Water that was pumped from the drill hole in 2015 was analyzed for dissolved gas concentrations and for major and trace element chemistry (Hurwitz et al., 2016; McCleskey et al., 2022).
 
The data release reports temperature-depth data from drill hole Y-7 measured 6 times between March 2002 and April 2015 under research permit YELL-SCI-5290. In March 2002, September 2002, June 2003, and June 2004, temperature was measured with a K-type thermocouple wire that was labeled every 5 feet. The thermocouple wire was connected to a handheld pre-calibrated temperature logger. Depth measurements are referenced to the top of the wellhead and were made at intervals of 10 or 20 feet with a depth accuracy of 1 foot. Temperature accuracy is 0.5 °C. The thermocouple was held at every measurement depth until no temperature changes were observed.
 
In April 2012 and April 2015, temperature measurements were made with the stop-go temperature logging method (Harris and Chapman, 2007) using the USGS portable temperature-measuring gear with a hand-cranked cable reel with four-conductor wire and a calibrated platinum resistance temperature (PRT) sensors that typically provide an accuracy of 0.1°C and precision of 0.01°C. The PRT probe was lowered into the well over a sheave and temperature was measured at depth intervals of 5 or 10 feet with a depth resolution conservatively estimated at ± 1 foot. The PRT probe was held at every measurement depth until no temperature changes exceeding 0.1°C were observed. Periodic calibration checks of the PRT probe were performed in a temperature-controlled water bath using an ASTM certified mercury thermometer in a USGS laboratory in Menlo Park, California.
 
The column headers in the data file (Y-7_Temperature_Depth.csv) are the depth of the temperature measurement in feet and in meters and the dates of the temperature measurement (month/day/year).
 
References cited
Harris, R.N. and Chapman, D.S., 2007. Stop-go temperature logging for precision applications. Geophysics, 72, E119-E123. https://doi.org/10.1190/1.2734382
Hurwitz, S., Clor, L.E., McCleskey, R.B., Nordstrom, D.K., Hunt, A.G. and Evans, W.C., 2016. Dissolved gases in hydrothermal (phreatic) and geyser eruptions at Yellowstone National Park, USA. Geology, 44, 235-238. https://doi.org/10.1130/G37478.1
Keith, T.E., White, D.E., and Beeson, M.H. 978. Hydrothermal alteration and self-sealing in Y-7 and Y-8 drill holes in northern part of Upper Geyser Basin, Yellowstone National Park, Wyoming. U.S. Geological Survey Professional Paper, 1054, p.26. https://doi.org/10.3133/pp1054A
McCleskey, R.B., Roth, D.A., Nordstrom, D.K., Hurwitz, S., Holloway, J.M., Bliznik, P.A., Ball, J.W., Repert, D.A., and Hunt, A.G., 2022, Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming: U.S. Geological Survey data release, https://doi.org/10.5066/P92XKJU7
Sturchio, N.C., Muehlenbachs, K. and Seitz, M.G., 1986. Element redistribution during hydrothermal alteration of rhyolite in an active geothermal system: Yellowstone drill cores Y-7 and Y-8. Geochimica et Cosmochimica Acta, 50, 1619-1631. https://doi.org/10.1016/0016-7037(86)90125-0
White, D.E., Fournier, R.O., Muffler, L.J.P., and Truesdell, A.H., 1975. Physical results of research drilling in thermal areas of Yellowstone National Park, Wyoming, U.S. Geological Survey Professional Paper, 892, 70 p. https://doi.org/10.3133/pp892
 
Acknowledgements
Laura Clor, Blaine McCleskey, and Fred Murphy from the USGS and Hank Heasler and Steven Miller from the Yellowstone Center for Resources at Yellowstone National Park are thanked for their assistance with temperature measurements.