Expedition 376 methods

Ronde, C. E. J. de; Humphris, Susan E.; Höfig, T.W.; Brandl, Philipp A.; Cai, Lanlan; Cai, Yanyan; Tontini, F. Caratori; Deans, J. R.; Farough, A.; Jamieson, John; Kolandaivelu, K. P.; Kutovaya, A.; Labonté, Jessica M.; Martin, Andrew J.; Massiot, Cécile; McDermott, J. M.; McIntosh, I. M.; Nozaki, Tatsuo; Pellizari, Vivian Helena; Reyes, Agnes G.; Roberts, Stephen; Rouxel, Olivier; Schlicht, L.E.M.; Seo, Jung Hun; Straub, Susanne M.; Strehlow, K.; Takai, Ken; Tanner, Dominique; Tepley, F. J.; Zhang, C.

doi:10.14379/iodp.proc.376.102.2019

Cited by 17 publications

(16 citation statements)

References 91 publications

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“…The volcanic rocks of Alteration Type I are unaltered to slightly altered (see Table T7 in the Expedition 376 methods chapter [de Ronde et al, 2019a]; Figure F6). The alteration mineral assemblage consists of smectite (identified by XRD analysis; Table T3) and Fe oxyhydroxides (identified visually) with minor zeolite (observed macroscopically).…”

Section: Alteration Type Imentioning

confidence: 99%

“…Microfractures are difficult to distinguish; however, minute delicate precipitates of halite and gypsum (from seawater) delineated microfractures once pieces were cut and dried, providing a stark contrast between the black dacite and the white precipitate. These intervals are logged as having minor brittle deformation (see Brittle deformation in the Expedition 376 methods chapter [de Ronde et al, 2019a]).…”

Section: Fracturesmentioning

confidence: 99%

“…Pore space dissolved gas concentration, including H 2 , CO, CH 4 , C 2 H 6 , and ΣCO 2 , were determined by headspace analysis of samples from Holes U1531A-U1531C (Table T7). For Sites U1528 and U1530 (see Geochemistry in the Expedition 376 methods chapter [de Ronde et al, 2019a]), we also measured the concentrations of pore fluid AVS.…”

Section: Volatile Geochemistrymentioning

confidence: 99%

“…Cores are commonly in multiple pieces of various length, so continuous measurements on whole-round cores (i.e., gamma ray attenuation bulk density, magnetic susceptibility [MS], and natural gamma radiation [NGR]) yielded poor data quality (see Physical properties in the Expedition 376 methods chapter [de Ronde et al, 2019a]). Measurements of P-wave velocity, density, porosity, MS, and thermal conductivity made on section halves and discrete samples, therefore, provide the basis for the petrophysical characterization of Site U1531.…”

Section: Physical Propertiesmentioning

confidence: 99%

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Site U1531

Ronde¹,

Humphris²,

Höfig³

et al. 2019

Proceedings of the International Ocean Discovery Program

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Background and objectives 3 Operations 6 Igneous petrology and volcanology 9 Alteration 10 Structural geology 10 Geochemistry 11 Paleomagnetism 13 Physical properties 15 Downhole measurements 15 Microbiology 16 References C.E.J. de Ronde et al. Site U1531 IODP Proceedings 2 V o l u m e 3 7 6 Hole U1531E. We could not advance any deeper because the TDCS core barrel got stuck in the bottom-hole assembly (BHA) and could not be retrieved. After the TDCS test, we cored with the RCB system from 17.9 to 39.6 mbsf and recovered only 0.8 m (4%). At this point, the blower motor in the top drive failed. We decided not to repair it at this time because of our remaining scientific priorities and the impending end of the expedition. Our final operation at Site U1531 consisted of a downhole temperature measurement with the Elevated Borehole Temperature Sensor (ETBS) memory tool. The tool recorded a maximum temperature of ~5°C at 20 mbsf. In total, 264.25 h, or 11.01 days, were spent at Site U1531. Principal results Igneous petrology and volcanology At Site U1531, one igneous unit was observed in Holes U1531A (0-1.14 mbsf), U1531B (0-21.97 mbsf), U1531C (0-23.75 mbsf), and U1531E (17.90-34.95 mbsf) as well as in several "ghost cores" from Hole U1531E. Igneous Unit 1 consists of unaltered to slightly altered plagioclase-pyroxene-phyric dacite lava intercalated with unconsolidated ash, ash with lapilli, and lapilli tephra with ash. The moderately to highly vesicular dacite lava contains glomerocrysts and phenocrysts of plagioclase, orthopyroxene, and clinopyroxene and Fe-Ti oxides in a cryptocrystalline and hypocrystalline groundmass. Volcaniclastic material is mainly composed of unaltered dacite clasts, crystals, and subordinate lithic components. The composition of the dacite lava and pyroclastic rocks from Site U1531 is similar to that of dacite cored in the upper sections at Sites U1527 and U1529. Alteration One alteration type was identified at Site U1531 based on an alteration assemblage identified using a combination of macroscopic and microscopic descriptions and X-ray diffraction (XRD) analyses. Alteration Type I is classified as slightly altered and has an alteration mineral assemblage of smectite, Fe oxyhydroxide, zeolite, pyrite, and rare native sulfur. Alteration occurs as infilling and lining of vesicles and smectite replacing the glassy matrix.

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Section: Alteration Type Imentioning

confidence: 99%

Section: Fracturesmentioning

confidence: 99%

Section: Volatile Geochemistrymentioning

confidence: 99%

Section: Physical Propertiesmentioning

confidence: 99%

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Site U1531

Ronde¹,

Humphris²,

Höfig³

et al. 2019

Proceedings of the International Ocean Discovery Program

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show abstract

“…At Site U1527, two igneous units were recovered ( Figure F8). Igneous Unit 1 consists of dacite lava and subordinate polymict lapilli tephra (see Table T2 in the Expedition 376 methods chapter [de Ronde et al, 2019a]). Dacite lava was recovered in Hole U1527A between intervals 5R-1, 0 cm, and 6R-1, 114 cm (38.80-49.64 mbsf), and in Hole U1527C in Cores 3R-10R (108.40-176.16 mbsf ) (Figure F8).…”

Section: Igneous Petrology and Volcanologymentioning

confidence: 99%