X-radiographs

Figure 7. Excess activity versus depth (left) and X-radiograph (right) in a sediment core collected from the New York Bight, showing the importance of mixing by benthic fauna in the upper part of the seabed. Abundant individnals of the small bivalve Nucula proximo may be seen in the X-radiograph near the sediment-water interface, and the light-colored areas represent bnrrows of Nephtys sp. and Ceriantheopsis sp. Reprinted from Estuarine Coastal and Shelf Science (formerly Estuarine and Coastal Marine Science) Vol. 9, Cochran and Aller, pp. 739-747, 1979, with permission from Elsevier Science.

Edmondson, W. T., and Allison, D. E., Recording densitometry of X radiographs for the study of cryptic laminations in the sediments of Lake Washington, Limnol. Oceanog.. 15. 138-144 (1970). 

Shelton, C.G, and Marks, P.R. (1988). Failure of ductile interlayer composites High resolution X-radiographic examination having an opaque penetrant. J. Mater. Sci. Lett. 7, 673-675. 

MacIntyre, I.G. and Smith, S.V., 1974. X-radiographic studies of skeletal development in coral colonies. Proc. Second Internat. Symp. on Coral Reefs, Great Barrier Reef Committee, Brisbane, 2 277—287. 

Fig. 5. X radiograph of an S. patens tussock. This x radiograph shows details of the internal structure of a relatively large tussock. The darker portions on the periphery and lower central part of the x radiograph are relatively rich in silt. The light-shaded region traversing the base of the tussock is composed of a mass of intertwined, 2-3-mm diam., rhizomes of, presumably, 5 patens. A number of similar plant parts are oriented vertically within the tussock, and very fine rootlets are evidently well dispersed throughout its entire volume, which extends some 10-12 cm above the adjacent surface of the marsh. Bar is 5 cm long.

The botannical studies of Richards (1934) and the x radiographs of Bouma (1963) show that inorganic-particle deposition can indeed lead vertical development where supplies are adequate. 

Fig. 4. X radiograph of vertical sediment section at FOAM. The upper 10-12 cm are characterized by abundant shell debris. A laminated layer at 4 cm is disrupted irregularly by shells and biogenic reworking activity. Parts of two vertical maldanid tubes can be seen in the center at a depth of 8-10 cm. Below 10-12 cm, the sediment begins to become laminated. This laminated zone begins at 8 cm in most x radiographs from FOAM (see Fig. 5). (Scale 3 cm.)...

Fig. 5. Parts of two vertically oriented x radiographs taken at FOAM. A massive shell layer of varied thickness (6-8 cm) overlies a well-laminated zone in both cases. There is relatively little evidence of biogenic structures although burrows can be made out in the shell layer. Beneath the laminated zone are additional shell layers down to at least SO cm. (Scale 3 cm.)...

Fig. 7. Vertically oriented x radiograph illustrating sedimentary features typical of NWC. The upper 4-6 cm is intensely hurrowed. Yoldia limatula can be seen at the far left and right of the radiograph. Abundant vertical burrows, due most probably to Owenia can be made out near the interface. A shell lag layer commonly found at this station occurs 6 cm and results from both feeding and storm activity. Bioturbate structure dominates at depth burrows coming out of plane of radiograph appear as light holes. (Scale 3 cm.)...

Fig. 8. X radiograph of 5-cm-thick horizontal slab of sediment 10-15 cm deep from NWC. The irregular distribution of shell debris can be seen with most shell material restricted to the right side of the radiograph. Remnants of maldanid tubes can be made out as can a single layer crustacean burrow (left) passing vertically down into the sediment. Maldanids are not presently a common, permanent faunal component at NWC but occur irregularly. (Scale 3 cm.)...

Fig. 10. Vertical x radiograph from DEEP. Maldanid dwelling tubes are abundant on right side. These commonly extend 20 cm into sediment. Shell debris is generally absent below a few centimeters. Where dwelling burrows are absent the sediment is characterized by a mottled, bioturbate texture (right side). (Scale 3 cm.)...

Fig. 11. Large burrow formed by unknown organism is seen in center of this x radiograph from DEEP. The wall is lined with clods of sediment and small pebbles. Surrounding sediment shows bioturbate structure typical of sediment that is not part of a contemporary dwelling structure. (Scale 3 cm.)...

The three stations chosen for study—FOAM, NWC, and DEEP—are located in predominantly silt-clay regions of central Long Island Sound and lie in 9,14, and 34 m of water, respectively. The location, description, faunal analysis, and examples of x radiographs of sediment at these stations are given in detail in this volume. Part I, p. 238, and will not be repeated here. The three stations represent a general inshore-offshore transect running from FOAM to DEEP. 

Another major area of iodine use is in pharmaceuticals, primarily in the form of radiopaque media, which are injected intravenously to produce X-radiographs of the internal structure of the body, for example. 

Figure 3. Laminaled sediment from Lake Kassjdn, Sweden (a) X-radiograph (b) BSEI photograph showing three-component varves. Key (I) terrigenous, graded sills (white) deposited during snow melt in May ...

X-radiograph An image produced by exposure of a sample material and photographic paper to an x-ray source. Samples with higher density will attenuate the x-ray more than lower density samples, thus decrease the exposure of the photographic paper. 

Figure 7. (A) X-radiograph of a cross-sectional slice of sample 1 annual bands are indicated by index lines and dates arrows show the locations of (B) dated radioactivity bands. (B) Autoradiograph of sample 1, with dates of test series associated with observed bands. (C) X-radiograph of sample 2 the circles indicate the locations of intraseasonal bands less intense or less continuous, or both, than the annual bands. (D) Autoradiograph of sample 2. The pictures are positives printed from X-ray negatives, so that dark areas correspond to the denser portions of the coral. To index bands near the center of the coral, half of each radiograph is shown. From Knutson et al. (1972). Copyright 1972 by the American Association for the Advancement of Science.

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