Nuclear magnetic resonance properties of marine sediments from the Nankai Trough

Author(s): Thomas, B.; Daigle, H.
Author Affiliation(s): Primary:
Vanderbilt University, Department of Chemical and Biomolecular Engineering, Nashville, TN, United States
University of Texas at Austin, United States
Volume Title: AGU 2013 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2013; American Geophysical Union 2013 fall meeting, San Francisco, CA, Dec. 9-13, 2013. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: We performed nuclear magnetic resonance (NMR) measurements of longitudinal (T1) and transverse (T2) relaxation times on samples from Integrated Ocean Drilling Program (IODP) Expedition 333 Sites C0011, C0012, and C0018. We compared these measurements with independent measurements of pore size distribution and permeability to develop methods for determining pore structure and permeability directly from NMR data. Geometric means of the T1 and T2 distributions ranged from 0.87 to 7.95 and 0.45 to 6.04 ms, respectively. We compared the T1 and T2 distributions to pore size distributions determined from Mercury Injection Capillary Pressure (MICP) measurements to determine the longitudinal and transverse surface relaxivities, which link relaxation time distribution to pore size. Longitudinal and transverse surface relaxivities ranged generally from 12.2 to 21.8 and 17.51 to 44.04 µm/s, respectively, with one outlier from the sediment-basement interface at Site C0012 having relaxivity values of 256.9 and 335.6 µm/s. Larger surface relaxivities were found to correlate with higher iron content in the sediments. The ratio of the geometric means of the relaxation time distributions (T1LM/T2LM) and the ratio of the surface relaxivities ( 2/ 1) both increase linearly with magnetic susceptibility, but magnetic susceptibility displays no relationship with the individual relaxation times or surface relaxivities. We additionally compared T2 values to measured permeabilities using the Schlumberger-Doll Research (SDR) equation. SDR equation coefficient A values were generally in the range of 7×10-18 to 8×10-17 m2/ms2 (0.007 to 0.080 mD/ms2). A is inversely correlated with clay-size particle fraction and specific surface, which suggests that A is mainly controlled by changes in pore or grain structure rather than mineralogy. Our results provide constraints for NMR determinations of pore size and permeability in marine sediments and illustrate the links between NMR properties, mineralogy, and grain size.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Cores; IODP Site C0011; IODP Site C0012; IODP Site C0018; Integrated Ocean Drilling Program; Marine sediments; NanTroSEIZE; North Pacific; Northwest Pacific; Pacific Ocean; Sediments; Shikoku Basin; West Pacific
Coordinates: N330925 N330925 E1364053 E1364053
N324453 N324453 E1365501 E1365501
N324944 N324945 E1365256 E1365254
Record ID: 2015031181
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