In 1949 a large bastn8site deposit was discovered at Mountain Pass, Cal if. Subsequent development of the deposit made the Uni ted States the worl d's largest source of rare-earth minerals. Since 1965, bastnisi te, a f luocarbonate of the cerium-group metals, REFC03, has replaced monazite as the principal source of rare earths; in 1978 it accounted for more than ha l f of the world production (§_).3 Rare-earth a lloys and compounds are used in petroleum crac.kin.g catalysts, ductile iron and high-strength, lo..,..alloy (HSLA) steel production, high- energy pertn4lnent magnets, color tel evi si on pi cture tubes, glass polishing and decolorizing, and ceramics. <...>

The Bolivian Sub-Andean Zone (SAZ) corresponds to a Neogene thrust system that affects an about 10-km thick Palaeozoic to Neogene siliciclastic succession. The analysis of macro and microstructures and cement distribution in thrust fault zones shows that they are sealed by quartz at depths >
3 km, due to local silica transfer by pressure-solution/precipitation activated at temperatures >70–90
C. At shallower depths, faults have remained open and could be preferential drains for lateral flow of carbonate-bearing fluids, as shown by the occurrence of carbonate cements in fractures and their host-sandstone. Due to decreasing burial, resulting from foothill erosion during fault activity, critically buried fault segments can be affected by nonquartz-sealed structures that post-date initial quartz-sealed structures. The integration of textural, fluid inclusion and isotopic data shows that carbonates precipitated at shallow depth ( < 3 km), low temperature ( < 80
C) and relatively late during the thrusting history. Isotopic data also show that precipitation occurred from the mixing of gravity-driven meteoric water with deeper formation water bearing carbonate carbon derived from the maturation of hydrocarbon source rocks (Silurian and Devonian shales). The combined microstructural and isotopic analyses indicate that: (i) fluid flow in fault zones often occurred with successive pulses derived from different or evolving sources and probably related to episodic fault activity, and (ii) at a largescale, the faults have a low transverse permeability and they separate thrust sheets with different fluid histories. 

The fluid is sealed in the host crystal, as an independent closed system of the phase boundary. To understand this definition, the following geological terms are carefully expanded:

(1) The diagenetic and ore-forming fluids in the definition refer to the fluid media, such as magma, solution, and gases around the main minerals, from which the inclusions are captured. They do not include the media’s debris such as crystal chips, cuttings, and crystals.

Fluid mechanics forms an essential part of the knowledge of petroleum engineers. Its applications can be found in almost every area of petroleum engineering including drilling, well completing, production technology, transportation and refining. The design methods and everyday practice of these special fields apply their own application-oriented hydraulics. These independently developed branches of applied fluid mechanics are often not very well integrated. There seems to be a need to treat these individual sections together within the general framework of continuum mechanics. In addition, the elegance and logical structure of this theory may influence the way of thinking of petroleum engineers. <...>