Characterizing gastrolith surface roughness with light scattering

Johnston, Roger G.; Manley, Kim; Lemanski, Cheryl L.

doi:10.1016/0030-4018(90)90383-5

Cited by 10 publications

(8 citation statements)

References 8 publications

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“…We assume in this study that moa gastroliths are more pol ished, at least on average, than non-gastroliths. Results from the previous dinosaur study (Johnston et al, 1990) offer some support for this idea. It should be noted, however, that the degree of surface smoothness for a given gastrolith probably depends strongly on the length of time the rock was retained in the gizzard and on its depositional environment after leaving the gizzard.…”

Section: Experimental Method Materials and Assumptionsmentioning

confidence: 73%

“…The previous light scattering study involving dinosaur gas troliths (Johnston et al, 1990) used a rotating arm to measure scattering intensity as a function of scattering angle. Only mea surements in the horizontal scattering plane could be made.…”

Section: Experimental Method Materials and Assumptionsmentioning

confidence: 99%

“…A particularly striking characteristic of gastroliths is that they are highly polished, presumably as a result of abrasive processes within the animal's gizzard. In previous work (Johnston et al, 1990), laser light scattering was used to characterize the surface roughness of known and suspected dinosaur gastroliths. They were found to be much smoother than fluvial rocks of similar composition that had been polished naturally in a stream.…”

Section: Introductionmentioning

confidence: 99%

“…As previously discussed (Johnston et al, 1990), light scatter ing has several significant advantages for analyzing gastroliths. It is fast, quantitative, nondestructive, and relatively inexpen sive.…”

Section: Introductionmentioning

confidence: 99%

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Identifying moa gastroliths using a video light scattering instrument

Johnston

Lee²,

Grace³

1994

J. Paleontol.

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When not found with fossil bone, gastroliths (fossil gizzard stones) may be hard to identify. One attribute that is potentially useful is their high degree of surface polish, presumably caused by abrasion in the animal's gizzard. A novel video laser light scattering instrument is used to characterize the surface roughness of suspected moa gastroliths, as well as similar (non-gastrolith) quartz rocks that were polished by ocean waves. The instrument is fairly successful at distinguishing between the two types of samples.

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Section: Experimental Method Materials and Assumptionsmentioning

confidence: 73%

Section: Experimental Method Materials and Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Identifying moa gastroliths using a video light scattering instrument

Johnston

Lee²,

Grace³

1994

J. Paleontol.

Self Cite

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“…Measurements of the shape distribution of stomach stones from a sauropod dinosaur from the Cedar Mountain Formation have shown that most are oblate spheroids (Sanders et al, 2001). Multiple studies of surface polish and smoothness have been done using a light-scattering instrument, indicating that dinosaur stomach stones have a comparatively high surface polish relative to other well-rounded and polished stones (Johnston et al, 1990;Johnston et al, 1994;Manley, 1991;Manley, 1993;Sanders et al, 2001). Most recently, studies have been done using a scanning electron microscope (SEM) to examine the microscopic surface texture of various stomach stones including moa (Johnston et al, 1994), alligator and ostrich gastroliths, and plesiosaur and sauropod dinosaur paleogastroliths (Schmeisser and Flood, 2004).…”

Section: Introductionmentioning

confidence: 97%

Recognition of Paleogastroliths from the Lower Cretaceous Cedar Mountain Formation, Utah using a Scanning Electron Microscope

Schmeisser

Flood

2008

Ichnos

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Paleogastroliths, as defined in this study, are stomach stones associated exclusively with extinct animals. Definitive recognition of paleogastroliths is problematic and controversial. Polished, rounded stones found within skeletal remains of dinosaurs and plesiosaurs are the strongest evidence. This study examined intraskeletal and proposed paleogastroliths using a scanning electron microscope (SEM) to determine if any defining surface textures occur. Paleogastroliths associated with the skeletal remains of Seismosaurus hallorum, possible paleogastroliths from the Lower Cretaceous Cedar Mountain Formation, and other well-polished stones were obtained. Most stones were composed of either quartzite or chert and were examined with a SEM at magnifications ranging from 100× to 400×. All of the cherty Seismosaurus hallorum stones contained sets of parallel to sub-parallel, curved polish grooves that in places crosscut one another. These grooves are inferred to have formed as the result of small particles lodged in the stomach muscles interacting with the stones due to muscle movement. The distinctive surface textures noted on the cherty Seismosaurus hallorum paleogastroliths are similar to those seen on the cherty possible paleogastroliths from the Cedar Mountain Formation. Therefore, the geologic occurrence combined with the microscopic surface texture supports the interpretation that these stones are paleogastroliths.

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