Inclusions


Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.

Inclusions

 

in minerals, foreign solid, liquid, and gaseous substances, enclosed by minerals during the growing process and trapped inside their crystals. The distribution of inclusions can be random or it can be distinguished by a regular orientation, determined by the crystalline properties of an enclosing mineral. Various minerals have solid inclusions— rutile, mica, ilmenite, and others. These inclusions sometimes endow certain qualities to minerals, which allow them to be used as decorative gems (for example, aventurine is a variety of quartz with inclusions of the tiniest bits of mica that give it a special sparkling shine). The most wide-spread inclusions are those of liquids and gases, which occur in various proportions in the voids of the inclusion and are called gaseous-liquid inclusions. Their liquid phase is a salt solution, usually containing sodium, potassium, chlorine, bicarbonate, and other ions and often containing liquid carbon dioxide. The gaseous phase of inclusions may contain hydrogen, oxygen, nitrogen, hydrogen sulfide, sulfur dioxide, carbon dioxide, and other gases. The size of inclusions varies from microscopic to those visible by an unaided eye. The number of inclusions varies and may reach tens of thousands in 1 mm3.

The study of inclusions helps determine the physical and chemical conditions of processes of mineral formation: temperature (geological thermometry), pressure, the chemical composition of mineral-forming solutions, and other properties. Thus, for example, inclusions of glass show that the mineral was formed from melted magma; the presence of liquid carbon dioxide proves that the mineral grew under high pressure. It is possible to deduce the temperature of formation of inclusions from the temperature to which the mineral must be heated to make the liquid-gaseous inclusions observed under a microscope become homogenous again (homogenization method). This is based on the hypothesis that at the time of the trapping of the inclusion in the body of the mineral, the trapping medium in which the mineral grew was homogenous, but on cooling of the mineral heterogeneity of the trapped inclusion occurred. The increase in pressure within inclusions during heating leads to their cracking (decrepitation). The decrepitation temperature may be registered by various methods, and the temperature at which inclusions form (splitting method or decrepitation) can be determined from it. At the present time methods are being worked out for seeking out hidden ores using inclusions (decreptophonic and dehydration methods).

REFERENCES

Ermakov, N. P. Isledovaniia mineraloobrazuiushchikh rastvorov. Kharkov, 1950.
Khitarov, D. N. “Izuchenie sostava i drugikh osobennostei gazovozhidkikh vkliuchenii v mineralakh na sovremennom etape.” In the collection Mineral’nye mikrovkliucheniia. Moscow, 1965.

D. N. KHITAROV

References in periodicals archive ?
Due to the typical purging bubble sizes: [less than or equal to] 5 mm (5,000 pm) encountered during rotary degassing, inclusions greater than 30 to 40 pm may be reliably separated from the melt by flotation.
956 inclusion in a subsequent year before the Subpart F income recapture account is fully recaptured.
Barry Callebaut ClibcMelts[TM] inclusions can be blended with ice cream via a standard fruit feeder.
There has been very little discussion of acidophilic intranuclear inclusions in the literature, and to the best of our knowledge there has been no study of their incidence and specificity in proliferative breast lesions.
Other studies on silicate inclusions have also confirmed their brittle nature at low temperature and increased plasticity above a certain critical temperature (Waudby, 1972; Mauder and Charles, 1968; Kiessling, 1978; Ekerot, 1974; Baker and Gove et al.
1990) classified the inclusions into three types: epithelial, nevomelanocytic and decidual.
The primary failure mode in the standard cleanliness material was inclusion based.
Fluid inclusions were considered curiosities until Sorby saw the mineral-encased bubbles as clues to processes that create rocks and minerals.
The idea behind inclusion is that every child should be an equally valued member of the school culture.
Sulfide-rich inclusions remain molten slightly longer than the rest of the steel and attract chromium atoms from adjacent zones.
With respect to the fluid inclusions, the question becomes: "What are the minimum temperatures and compositions of the hydrothermal fluids from which the minerals in the veins and vugs formed at the Sweet Home mine?
The company provides fruity/sweet/brown flavor inclusions such as apple, cinnamon, maple, blueberry, raspberry, chocolate and vanilla.

Full browser ?