Context: In geology, felsic refers to igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron. It refers to those rocks rich in silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium., Feldspars (KAlSiO  NaAlSiO  CaAlSiO) are a group of rock-forming tectosilicate minerals that make up as much as 60% of the Earth's crust., Igneous rock (derived from the Latin word "ignis" meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. , The mineral olivine is a magnesium iron silicate with the formula (Mg, Fe)SiO. Thus it is a type of nesosilicate or orthosilicate. It is a common mineral in the Earth's subsurface but weathers quickly on the surface., The pyroxenes (commonly abbreviated to "Px") are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes are silicon-aluminum oxides with Ca, Na, Fe, Mg, Zn, Mn, Li substituting for Si and Al. The general formula is XY(Si,Al)O (where X represents calcium, sodium, iron and magnesium and more rarely zinc, manganese and lithium and 
Y represents ions of smaller size, such as chromium, aluminium, iron, magnesium, cobalt, manganese, scandium, titanium, vanadium and even iron). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems., Earth, otherwise known as the world, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets., Iron is a chemical element with symbol Fe (from ) and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Its abundance in rocky planets like Earth is due to its abundant production by fusion in high-mass stars, where it is the last element to be produced with release of energy before the violent collapse of a supernova, which scatters the iron into space., Amphibole is the name of an important group of generally dark-colored, inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups., Quartz is the second most abundant mineral in Earth's continental crust, after feldspar. Its crystal structure is a continuous framework of SiO siliconoxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO., Silicon is a chemical element with symbol Si and atomic number 14. A hard and brittle crystalline solid with a blue-gray metallic luster, it is a tetravalent metalloid. It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, lead, and flerovium below. It is rather unreactive, though less so than germanium, and has great chemical affinity for oxygen; as such, it was first prepared and characterized in pure form only in 1823 by Jöns Jakob Berzelius., Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more properly known as the plagioclase feldspar series (from the Ancient Greek for "oblique fracture", in reference to its two cleavage angles). This was first shown by the German mineralogist Johann Friedrich Christian Hessel (17961872) in 1826. The series ranges from albite to anorthite endmembers (with respective compositions NaAlSiO to CaAlSiO), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Plagioclase in hand samples is often identified by its polysynthetic crystal twinning or 'record-groove' effect., Mafic is an adjective describing a silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of magnesium and ferric. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, dolerite and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase feldspar. , Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (Group 2, or alkaline earth metals) of the periodic table: all Group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure., A lithosphere (["lithos"] for "rocky", and ["sphaira"] for "sphere") is the rigid, outermost shell of a terrestrial-type planet or natural satellite that is defined by its rigid mechanical properties. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. The outermost shell of a rocky planet, the crust, is defined on the basis of its chemistry and mineralogy., In geology, the sial refers to the composition of the upper layer of the Earth's crust, namely rocks rich in silicates and aluminium minerals. It is sometimes equated with the continental crust because it is absent in the wide oceanic basins, but "sial" is a geochemical term rather than a plate tectonic term. As these elements are less dense than the majority of the earth's elements, they tend to be concentrated in the upper layer of the crust., Aluminium or aluminum (in North American English) is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminium is the third most abundant element in the Earth's crust (after oxygen and silicon) and its most abundant metal. Aluminium makes up about 8% of the crust by mass, though it is less common in the mantle below. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. The chief ore of aluminium is bauxite., Gabbro refers to a large group of dark, often phaneritic (coarse-grained), mafic intrusive igneous rocks chemically equivalent to basalt. It forms when molten magma is trapped beneath the Earth's surface and slowly cools into a holocrystalline mass., Magma (from Ancient Greek  ("mágma") meaning "thick unguent") is a mixture of molten or semi-molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion. Magma is capable of intruding into adjacent rocks (forming igneous dikes and sills), extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock., Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula . More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous end-members include siderophyllite. Biotite was named by J.F.L. Hausmann in 1847 in honor of the French physicist Jean-Baptiste Biot, who, in 1816, researched the optical properties of mica, discovering many properties., Sodium is a chemical element with symbol Na (from Latin "natrium") and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell that it readily donates, creating a positively charged atomthe Na cation. Its only stable isotope is Na. The free metal does not occur in nature, but must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust, and exists in numerous minerals such as feldspars, sodalite and rock salt (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans., The Conrad discontinuity corresponds to the sub-horizontal boundary in continental crust at which the seismic wave velocity increases in a discontinuous way. This boundary is observed in various continental regions at a depth of 15 to 20 km, however it is not found in oceanic regions., The continental crust is the layer of igneous , sedimentary , and metamorphic rocks that forms the continents and the areas of shallow seabed close to their shores , known as continental shelves . This layer is sometimes called sial because its bulk composition is more felsic , or granitic , in contrast to the oceanic crust , called sima , whose bulk composition is more mafic or basaltic rock . ( Based on the change in velocity of seismic waves , it is thought that at a certain depth sial becomes to sima close in its physical properties . This line is called the Conrad discontinuity . ) Consisting mostly of granitic rock , continental crust has a density of about 2.7 g / cm3 and is less dense than the material of Earth 's mantle , which consists of ultramafic rock and whose density is about 3.3 g / cm3 . Continental crust is also less dense than oceanic crust , whose density is about 2.9 g / cm3 . Continental crust is considerably thicker than oceanic crust , mostly 25 to 70 km versus the average thickness of the oceanic crust of around 7 -- 10 km. About 40 % of Earth 's surface is now overlaid by continental crust . Continental crust makes up about 70 % of the volume of Earth 's crust ., Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together constitute oceanic lithosphere., Seismic waves are waves of energy that travel through the Earth's layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy. Many other natural and anthropogenic sources create low-amplitude waves commonly referred to as ambient vibrations. Seismic waves are studied by geophysicists called seismologists. Seismic wave fields are recorded by a seismometer, hydrophone (in water), or accelerometer., Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms oxides with most elements as well as other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . This is an important part of the atmosphere and diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. Additionally, as oxides the element makes up almost half of the Earth's crust., Potassium is a chemical element with symbol K (derived from Neo-Latin, "kalium") and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals. All of the alkali metals have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge  a cation, which combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction and burning with a lilac-colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight), and is part of many minerals., Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of rock-forming minerals and make up approximately 90 percent of the Earth's crust. They are classified based on the structure of their silicate groups, which contain different ratios of silicon and oxygen., Geology (from the Ancient Greek , "g", i.e. "earth" and -o, "-logia", i.e. "study of, discourse") is an earth science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any terrestrial planet (such as the geology of the Moon or Mars)., A portmanteau (; plural "portmanteaus" or "portmanteaux" ) or portmanteau word is a linguistic blend of words, in which parts of multiple words or their phones (sounds) are combined into a new word. 
as in "smog", coined by blending "smoke" and "fog", or "popportunity", from "popping" and "opportunity", or "motel", from "motor" and "hotel". In linguistics, a portmanteau is defined as a single morph that represents two or more morphemes., Basalt (, , , or ) is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of lava basalt flows., Subject: continental crust, Relation: part_of, Options: (A) bind (B) class (C) earth (D) electron shell (E) english (F) gas (G) geology (H) german (I) green (J) hand (K) life (L) linguistics (M) lithosphere (N) mantle (O) mars (P) mass (Q) mixture (R) moon (S) name (T) nature (U) part (V) periodic table (W) rock (X) science (Y) sea (Z) series ([) shell (\) solid (]) word
Output: lithosphere