Articles | Volume 31
https://doi.org/10.5194/sd-31-71-2022
https://doi.org/10.5194/sd-31-71-2022
Technical development
 | 
28 Oct 2022
Technical development |  | 28 Oct 2022

A channel sampling strategy for measurement of mineral modal and chemical composition of drill cores: application to lower oceanic crustal rocks from IODP Expedition 345 to the Hess Deep rift

Robert P. Wintsch, Romain Meyer, David L. Bish, Ryan T. Deasy, Toshio Nozaka, and Carley Johnson

Related subject area

Location/Setting: Drilling technologies | Subject: Geology | Geoprocesses: Earth science methods
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Sci. Dril., 31, 85–91, https://doi.org/10.5194/sd-31-85-2022,https://doi.org/10.5194/sd-31-85-2022, 2022
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Cited articles

Agterberg, F. P.: Sampling and analysis of chemical element concentration distribution in rock units and orebodies, Nonlin. Processes Geophys., 19, 23–44, https://doi.org/10.5194/npg-19-23-2012, 2012. 
Arai, S. and Matsukage, K.: Petrology of gabbro-troctolite-peridotite complex from Hess Deep, equatorial Pacific: implications for mantle-melt interaction within the oceanic lithosphere, in: Proc. ODP, Sci. Results, College Station, TX (Ocean Drilling Program), edited by: Mével, C., Gillis, K. M., Allan, J. F., and Meyer, P. S., 147, 135–155, https://doi.org/10.2973/odp.proc.sr.147.008.1996, 1996. 
Arai, S. and Takemoto, Y.: Mantle wehrlite from Hess Deep as a crystal cumulate from an ultra-depleted primary melt in East Pacific Rise, Geophys. Res. Lett., 34, L08302, https://doi.org/10.1029/2006GL029198, 2007. 
Bish, D. L. and Post, J. E.: Quantitative mineralogical analysis using the Rietveld full-pattern fitting method, Am. Min., 78, 932–940, 1993. 
Bish, D. L., Sarrazin, P., Chipera, S. J., Vaniman, D. T., and Blake, D.: Quantitative mineralogical analysis of Mars analogues using CHEMIN data and Rietveld refinement, 35th Lunar and Planetary Science Conf., 2004: The Future of Mars Surface Exploration, 15–19 March 2004, League City, Texas, USA, 35, 1404, ID: 20040065952, 2004. 
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We report a new method of obtaining representative samples of drill core with an example from the lower oceanic crust in the Hess Deep rift. Sawing drill core in half produces 1.3 g of rock per centimeter of core cut – material usually discarded. We show that when collected and analyzed properly, these samples reveal both the chemical composition of lower oceanic crust and the reactions that change the mineralogical and chemical composition of that crust.