Quartz rocking curve

Another important parameter that may affect the resolution is the higher harmonic contribution from the Bragg reflector. A fused quartz mirror behind the monochromator has been currently used to reject this high harmonic contribution. Therefore, the energy resolution of the spectrometer is just limited by the Darwin width of the rocking curve and the spatial resolution of the position-sensitive detector [8]. 

TiKa, and finally fourth order MnKa and CrKB 3 occur. Using the X-ray diffraction dynamical theory the rocking curves for quartz (010)... 

Figure 5.71A shows univariant equilibrium curves for various molar amounts of ferrous component in the orthopyroxene mixture. The P-T field is split into two domains, corresponding to the structural state of the coexisting quartz (a and j3 polymorphs, respectively). If the temperature is known, the composition of phases furnishes a precise estimate of the P of equilibrium for this paragenesis. Equation 5.277 is calibrated only for the most ferriferous terms, and the geobarometer is applicable only to Fe-rich rocks such as charnockites and fayalite-bearing granitoids. 

Figure 2,5 (a) An Arrhenius plot of log k versus I/TXK) for the dissolution rates of various silicate rocks and minerals. The data points and curves for rhyolite, basalt glass, and diabase are from Apps (1983), as is the curve labeled silicates, which Apps computed from the results of Wood and Walther (1983). Curves for the S1O2 polymorphs are based on Rimstidt and Barnes (1980). Modified from Langmuir and Mahoney (1985). Reprinted from the National Well Water Assoc. Used by permission, (b) An Arrhenius plot of log k versus 1 /T(K) for the precipitation of quartz and amorphous silica based on Rimstidt and Barnes (1980). Reprinted from Geochim. Cosmochim. Acta, 44, J.D. Rimstidt and H.L. Barnes, The kinetics of silica water reactions, 1683-99, 1980, with permission from Elsevier Science Ltd, The Boulevard. Langford Lane. Kidlington OXS 1GB, U.K. 

Obviously there are several mineral associations which can be used to define silica activity. Several reactions which correspond to some associations of importance in igneous rocks are listed in Table 1. Among these associations is the single mineral quartz which is characteristic of the oversaturated rocks in Shand s classification. It is noteworthy that because quartz is nearly pure Si02 melts in equilibrium with this mineral will have silica activities that, for all practical purposes, lie exactly on the curve labeled Q in Figure 1. Reaction (1) characterizes the tholeiite basalts (Carmichael et al., 1974 Tilley, 1950)... 

As rocks belonging to the tholeiite suite generally contain normative quartz and, in the more siliceous varieties, modal quartz as well, melts corresponding to lavas in this suite should have silica activities between curves 1 and 2 (Figure 1). 

Shortly after sunrise, about 7 00-8 00, quartz is warmer than schist. At midnight, the two rocks are at about the same temperature. These observations, incidentally, have an exceptional value if, instead of two measurements in 24 h, we could have a series of observations (enabling us to draw curves similar to those in Figure 18), it would be possible to identify most rock, soil, and plant formations provided we had control curves in sufficient number the parameters of such curves would be stored in the computer. 

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