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131.
Charles M. Onasch 《Tectonophysics》1984,110(1-2)
Compression and extension axes are deduced from quartz deformation lamellae in a quartzite and a graywacke folded into an asymetrical syncline. Deformation lamellae fabrics in the two sandstones are distinctly different. In the graywacke, regardless of bedding orientation or position on the fold, compression axes are normal or nearly normal to the axial planar rough cleavage. Extension axes generally lie in the cleavage plane, parallel to dip. In most quartzite samples, compression axes are parallel or subparallel to bedding, at high angles to the fold axis and extension axes are normal to bedding. Two samples from the very base of the formation indicate compression parallel to the fold axis with extension parallel to bedding, at high angles to the fold axis. One of these two shows both patterns. The lamellae fabric geometry in these two samples suggests the presence of a neutral surface in the quartzite. The lamellae-derived compression and extension axes are in good agreement with the buckling behavior of a viscous layer (quartzite) embedded in a less viscous medium (graywacke and shale below and shale and carbonate above). 相似文献
132.
Estuaries and Coasts - A coring system using a compressed air supply and a sediment shaking procedure using a soil dispersant are described which greatly simplify and shorten the task of... 相似文献
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Iron (II) oxide in 50 mg samples of silicate rocks, deposits, and soils is measured after digestion with HF and HCl in the presence of ICl. The iodine produced is measured spectrophotometrically. Results are presented for the eighteen available USGS geochemical reference standards including the GXR series. 相似文献
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138.
Radiocarbon dates indicate a Farmdalian through Woodfordian age for fossil white spruce (Picea glauca) in the Tunica Hills, a greater time span than previously documented. These dates, furthermore, require revision of the ages of fluvial terrace deposits in the region. Spruce-bearing Terrace 1 sediments, previously regarded as late Woodfordian to Holocene age, are of Farmdalian to late Holocene age. Terrace 2 sediments, previously assigned a Sangamonian or Farmdalian age, are of probable Altonian age. Plant fossils in Terrace 1 sediments represent two climatically and temporally distinct assemblages: a cool-temperate, Farmdalian-Woodfordian assemblage dominated by white spruce but including deciduous hardwoods suggestive of an oak-hickory association; and a warm-temperate Holocene assemblage composed of southern hardwoods and nonarboreal species representative of the modern flora of the Tunica Hills. Locally, fossils of white spruce have been reworked into younger Terrace 1 sediments containing the warm-temperate plant assemblage. The transition from the cool-temperate flora to the modern warm-temperate flora in the Tunica Hills probably occurred around 12,000 yr B.P. 相似文献
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140.
Charles R. Schwarz 《Journal of Geodesy》1982,56(2):165-176
There are many data base management systems now available as commercially marketed software packages. Although most of these
packages were initially aimed at bussiness or administrative data processing applications, they may frequently also be the
right tool for a scientific data processing task. This becomes more apparent as we notice that scientific computer programmers
are spending more and more time on data management requirements rather than the coding of mathematical algorithms.
In a scientific environment, a generalized data base management package is best viewed as a tool for programmers, rather than
as a tool for direct, independent use by end users or by agency management. To the end user, the most attractive feature of
a commerical DBMS is usually the interactive retrieval and update language. To the programmer, the most attractive feature
is more likely to be the strong support for various types of keyed access. All of the manipulations necessary to build and
maintain indices and other tables can be treated as procedural abstractions. Coupled with a procedural language, a DBMS offers
the programmer a higher level (in the sense of more abstract) language. The most important geodetic requirement on a commercial
DBMS is therefore that the package contain a strong Data Manipulation Language, with strong support for the algorithmic language
used for scientific processing.
Presented at International Symposium on Management of Geodetic Data, Copenhagen, August 24–26, 1981. 相似文献