AMPHIBOLES and PYROXENES, and with SILICA occurring as quartz.
to the length of the side adjacent to it. Also, in geometry, a straight line that just touches the circumference of a circle.In geometry, the tangent line (or simply the tangent) to a curve at a given point is the straight line that "just touches" the curve at that point (in the sense explained more precisely below). As it passes through the point of tangency, the tangent line is "going in the same direction" as the curve, and in this sense it is the best straight-line approximation to the curve at that point. The same definition applies to space curves and curves in n-dimensional Euclidean space.
Similarly, the tangent plane to a surface at a given point is the plane that "just touches" the surface at that point. The concept of a tangent is one of the most fundamental notions in differential geometry and has been extensively generalized; see Tangent space.
The word "tangent" comes from the Latin tangere, meaning "to touch".
formation of evaporite deposits, notably CARBONATES and sulphates. It is named after the Trucial Coast in the Persian Gulf, sabkha being the Arabic word for salt flat.
object. Radar is used in the navigation of aircraft, ships, missiles and satellites.
In geometry, a quadrilateral is a polygon with four 'sides' or edges and four vertices or corners. Sometimes, the term quadrangle is used, for analogy with triangle, and sometimes tetragon for consistency with pentagon (5-sided), hexagon (6-sided) and so on. The word quadrilateral is made of the words quad and lateral. Quad means four and lateral means sides. The interior angles of a quadrilateral add up to 360 degrees of arc.
Quadrilaterals are simple (not self-intersecting) or complex (self-intersecting). Simple quadrilaterals are either convex or concave.
All convex quadrilaterals tile the plane by repeated rotation around the midpoints of their edges.
Palaeogeography (also spelled paleogeography) is the study of what the geography was in 
times past. It is most often used about the physical landscape, although nothing excludes its use in reference to the human or cultural environment. If the topic is landforms it could also be called paleogeomorphology.
In petroleum geology the term paleogeographic analysis is used for the detailed study of sedimentary basins, since the ancient geomorphological environments of the Earth's surface are preserved in the stratigraphic record. Paleogeographers also study the sedimentary environment associated with fossils to aid in the understanding of evolutionary development of extinct species. The reconstruction of prehistoric continents and oceans depends on paleogeographic evidence. Thus paleogeography provides critical evidence for the development of continental drift and current plate tectonic theories. For example, knowledge of the shape and latitudinal location of supercontinents such as Pangaea and ancient oceans such as Panthalassa result from paleogeographic studies.
Not to be confused with palaeography.
Mach number (Ma or M) (generally pronounced /ˈmɑːk/, sometimes /ˈmɑːx/ or /ˈmæk/) is the speed of an object moving through air, or any fluid substance, divided by the speed of sound as it is in that substance. It is commonly used to represent an object's (such as an aircraft or missile) speed, when it is travelling at (or at multiples of) the speed of sound.
where
is the Mach number
is the speed of the source (the object relative to the medium) and
is the speed of sound in the medium
radioactive ISOTOPE, which can be followed through a biological or physical system by means of the RADIATION it emits.
Ann Santos, that came when her idol Julie Vega died. When she learned about the soap opera star's death, Judy Ann disappeared, first into her room, then into the bathroom. She turned the doorknob quietly, pushed the door shut and stood in front of the sink. She looked at herself in the mirror -- then she cried.
to have their tampuhan, then when Mommy Carol left the country to work -- because of which she missed out on a great deal of Judy Ann's pre-teen years -- it gave them a chance to step back and take a good look at their relationship. "Sa lahat ng mag-iina, the time comes na nagkakaroon talaga ng misunderstandings at tampuhan. Ang katumbas ng tampuhan namin ni Mommy, pag nangyari, ligwak ang buong araw ko. But these things happen for the both of you to have a deeper relationship.
s. It was formed by the melting of stagnant ice which as a result dropped its load of sediment.
an impure variety of minutely crystalline quartz (SiO2). It is usually red, brown or yellow, and some varieties are banded, e.g. Egyptian or ribbon jasper.Jasper, a form of chalcedony , is an opaque, impure variety of silica, usually red, yellow, brown or green in color. Blue is rare. This mineral breaks with a smooth surface, and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and at one time for snuff boxes. When the colors are in stripes or bands, it is called striped or banded jasper. Jaspilite is a banded iron formation rock that often has distinctive bands of jasper. Jasper is basically chert which owes its red color to iron(III) inclusions. The specific gravity of jasper is typically 2.5 to 2.9.
Taken from Wikipedia
about the last ice age during the Pleistocene geological epoch 2 million years ago. However, geological studies show evidence of earlier ice ages although less is known about these.
and hydrogen in the presence of an iron CATALYST. The process gives a maximum yield (4o per cent) using relatively low temperatures and high pressures. The Haber process is important in industrial chemistry since it is the most economic way to produce ammonia, from which fertilizers are made.
