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3. Explanatory Notes1 Moore, G.F., Taira, A., and Klaus, A. (Eds.) Proceedings of the Ocean Drilling Program, Initial Reports Volume 190 3. EXPLANATORY NOTES1 Shipboard Scientific Party2 INTRODUCTION This chapter includes information on shipboard methods that will help the reader understand the basis for our preliminary interpretations and also help the interested investigator select samples for further anal- ysis. Coring techniques and core handling, including the numbering of sites, holes, cores, sections, and samples (Fig. F1), are the same as those F1. Diagram illustrating core, sec- reported in previous Initial Reports volumes of the Proceedings of the tion, and sample numbering, Ocean Drilling Program and are only briefly summarized. p. 33. ODP Leg 190 Core 190-1173B-2R Section 190-1173B-2R-5 Site 1173 Top Top (0 cm) Authorship of Site Chapters Section 1 Sea level Void Section 2 Water depth The separate sections of the site chapters were written by the follow- (m or mbsl) Section 3 ing shipboard scientists (authors are listed in alphabetical order; no se- Beacon Seafloor Core 1R 100% recovery Section 4 Sample niority is implied): 190-1173B- 2R-5, 80-85 cm Section 5 Core 2R Principal Results: Shipboard Scientific Party 90% recovery Not cored: drilled/washed Section 6 Operations: Pettigrew, Klaus Core 3R 50% recovery Penetration Core catcher (CC) Bottom (mbsf) (150 cm) Lithostratigraphy: Fergusson, Hirano, Stuerer, Wilson, Underwood Bottom of hole Hole 1173B Structural Geology: Maltman, Morgan, Sanchez-Gomez, Tobin, Ujiie Biostratigraphy: Boeckel Paleomagnetism: Dean, Hisamitsu Inorganic Geochemistry: Kastner, Spivack Organic Geochemistry: L. Becker Microbiology: Cragg, Murakami, Smith Physical Properties: Henry, Hunze, Saffer, Screaton Downhole Measurements: Tobin In Situ Temperature Measurements: K. Becker, Screaton 1Examples of how to reference the Seismic Stratigraphy: Moore whole or part of this volume. 2 Shipboard Scientific Party addresses. Ms 190IR-103 SHIPBOARD SCIENTIFIC PARTY CHAPTER 3, EXPLANATORY NOTES 2 Reference Depths Seafloor depths and cored intervals below seafloor (meters below sea- floor [mbsf]) are determined by drill-pipe measurement. Numbering of Sites, Holes, Cores, Sections, and Samples Drill sites are numbered consecutively from the first site drilled by the Glomar Challenger in 1968. A site refers to one or more holes drilled while the ship was positioned over a single acoustic beacon. The first hole drilled at a given site is assigned the site number modified by the suffix “A,” the second hole takes the site number and suffix “B,” and so forth. These suffixes are assigned regardless of recovery, as long as pene- tration takes place. Each cored interval is generally 9.5 m long, which is the length of a core barrel. Coring intervals may be shorter and may not necessarily be adjacent if separated by intervals drilled but not cored. The depth inter- val assigned to an individual core begins with the depth below the sea- floor at which the coring operation began and extends to the depth that the coring operation ended for that core. A recovered core is typically divided into 1.5-m-long sections that are numbered serially from 1 through 7 (or less if partial recovery) begin- ning at the top. When the recovered core is shorter than the cored in- terval, the top of the core is equated with the top of the cored interval by convention in order to achieve consistency in handling analytical data derived from the cores. Also by convention, material recovered from the core catcher is placed in a separate section during the core de- scription, labeled core catcher (CC), and placed below the last (bottom) section recovered in the liner. The core catcher is placed at the top of the cored interval in cases where material is only recovered in the core catcher. Samples removed from a core section are designated by distance measured in centimeters from the top of the section to the top and bot- tom of each sample removed from that section. A full identification number for a sample consists of the following information: leg, site, hole, core number, core type, section number, and top to bottom inter- val in centimeters measured from the top of section. For example, a sample identification of “190-1173B-26R-2, 20–25 cm” represents a sample removed from the interval between 20 and 25 cm below the top of Section 2. Core 26R designates that this core was taken during rotary core barrel coring of Hole 1173B from Leg 190. All ODP core identifiers indicate core type. The following abbrevia- tions are used: H = advanced hydraulic piston corer (APC); X = ex- tended core barrel (XCB); R = rotary core barrel (RCB). Core Handling As soon as a core is retrieved on deck, a sample is taken from the core catcher and, if sedimentary, given to the paleontological laboratory for an initial age assessment. The core liner with the core inside is marked into section lengths, each section is labeled, and the core is cut into sec- tions. If a whole-round sample is to be taken, the desired interval is identified, cut out of the core, and then the section are cut. When pos- sible, these samples are taken from the bottom of sections. During Leg 190, whole-round samples were taken for interstitial water (IW) analy- SHIPBOARD SCIENTIFIC PARTY CHAPTER 3, EXPLANATORY NOTES 3 ses, organic geochemistry, and microbiology as well as for postcruise permeability and consolidation/strength measurements. For safety monitoring, small (~5 cm3) plugs of sediment are taken from the end of one section per core for headspace gas analysis. If pockets of gas are present, a vacutainer gas sample is taken through the core liner. Each section is then sealed at the top and bottom by using acetone to seal color-coded plastic caps to the plastic core liner. A blue end cap marks the top of a section, a clear cap marks the bottom, and a yellow cap marks the end of a section from which a whole-round sample has been removed. The sample code (e.g., IW) is written on the yellow cap. The core sections are then carried into the laboratory, and the length of the core sections and any samples taken are logged into the shipboard database. After the core sections equilibrate to ambient lab temperature (~3 hr), they are run through the multisensor track (MST). For soft sedi- ments, thermal conductivity measurements are then made (see “Physi- cal Properties,” p. 19). Cores are subsequently split lengthwise into working and archive halves. The archive half is used for nondestructive measurements: visual core description, paleomagnetism, magnetic sus- ceptibility, and color reflectance. Samples were taken from the working half for shipboard physical properties measurements (see “Physical Properties,” p. 19) before being sampled for additional shipboard and postcruise studies. The archive halves were photographed a whole core at a time, and close-up photographs were taken as requested. Finally, the core sections were put into labeled plastic tubes, sealed, and trans- ferred to cold-storage space aboard the drilling vessel. Following the cruise, the cores were transported to the Gulf Coast Repository of the Ocean Drilling Program (ODP) in College Station, Texas. LITHOSTRATIGRAPHY Visual Core Descriptions We followed normal ODP procedures for recording sedimentologic information on visual core description (VCD) forms on a section-by- section basis (Mazzullo and Graham, 1988). VCD data were transferred to core-scale “barrel sheets” using AppleCORE software (Shipboard Sci- entific Party, 1997). Textural subdivisions for siliciclastic sediments and the classification scheme for siliciclastic lithologies follow Mazzullo et al. (1988). The “Graphic Lithology” column on each barrel sheet shows to scale all intervals that are at least 10 cm thick. Combined graphic F2. Graphic patterns and symbols patterns are used to indicate interbeds less than 10 cm thick. Differ- used on AppleCORE barrel sheets ences between the silty clay and clayey silt lithologies can be subtle and during Leg 190, p. 34. Lithology Physical Structure Deformation Structure not easily separated without further analysis, so we grouped this entire conglomerate coarsening upward normal fault gravel fining upward reverse fault range of sediment textures into the category “clayey silt” on all barrel sand or sandstone normal graded bedding fault silty sand reverse graded bedding foliated breccia scaly fabric sheets. Figure F2 displays the graphic patterns for all lithologies en- silt or siltstone planar tabular bedding planar laminae stratal disruption sandy silt ripple cross-laminae fracture, general clayey silt to silty clay conjugate fractures countered during Leg 190. Separate patterns have not been used for lenticular bedding sandy clay fracture network convolute bedding clay or claystone more heavily indurated examples of the same lithologies (e.g., sand vs. isolated lamina, color band fracture with brecciation sand/silt/clay silt lamina sigmoidal vein siliceous claystone sandstone). Also shown are symbols for internal sedimentary structures, sand lamina sediment-filled vein nannofossil ooze chaotic bedding calcite vein limestone slump folds vein deformation structures, and symbols for core disturbance in both soft boudin nannofossil chalk Lithologic Accessory fissility volcanic ash or tuff shale lamina stylolite sediment and indurated sedimentary rock. The “Samples” column on thin siliceous layer basalt deformation band thin calcareous layer void foliation thin ash layer the barrel sheets indicates the positions and types of samples taken Core Disturbance extracted core (sample) pebbles/granules disturbed patch of minor lithology soupy from each core for shipboard analyses. The abbreviations for these sam- Ichnofossil Zoophycos lithoclast biscuit Chondrites pumice fractured ples are as follows: IW = interstitial water; SS = smear slide; WRP = wood fragments slurry general nodule/concretion highly fragmented whole round for physical properties; WRB = whole round for microbiol- pyrite nodule breccia calcite cement pinch-and-swell fold SHIPBOARD SCIENTIFIC PARTY CHAPTER 3, EXPLANATORY NOTES 4 ogy; WHC = whole-core sample.
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