About This Item
- Full text of this item is not available.
- Abstract PDFAbstract PDF(no subscription required)
Share This Item
The AAPG/Datapages Combined Publications Database
Houston Geological Society Bulletin
Abstract
Abstract: Petrofabric Studies of Some Fine-Grained Rocks by Means of X-Ray Diffraction
By
Rice University Master of Arts thesis, 130 p., May, 1965
Crystallographic orientation in rocks too fine-grained to be studied optically
can be determined by X-ray diffraction. Absorption and geometric corrections
are unnecessary because, by studying hemispherical surfaces, absorption is
held constant. Poughquag quartzite, Star Mountain rhyolites, basalt and mylonites
were studied. All quartz crystals in the examined samples are parallel to c-axes.
The preferred orientations parallel to c-axes or a-axes of feldspar (orthoclase
or labradorite), microlites are more common than those perpendicular to c-axes
or a-axes of feldspar (orthoclase of labradorite) crystals in extrusive igneous
and highly deformed metamorphic rocks. In deducing the flow direction from
the fabric diagrams of rhyolitic or basaltic rocks, the preferential orientation
has been supposed to be parallel with the lava flow, while in case of highly
deformed mylonitic rocks the preferred orientation was considered to be
parallel to the movement direction. End_of_Record - Last_Page 16--------