Glossary of Basic Geological Terms
English term Czech term Explanation
ablation ablace The process of decreasing of ice volume of a glacier. Synonym wastage.
abrasion abraze The grinding away of a rock by friction and impact during transportation.
absolute age absolutní stáří Age given in years or some other unit of time (mostly in million of years).
abyssal fan abysální dejekční kužel Great fan-shaped deposit of sediment on the deep-sea floor at the base of many submarine canyons.
abyssal plain abysální rovina Very flat sediment-covered region of the deep-sea floor, usually at the base of the continental rise.
accessory minerals akcesorické minerály Rock-forming minerals which occur in a rock in a very small amount (several percents of mineral content) and which have no effect to classification of a rock.
acid rocks kyselé vyvřelé horniny Igneous rocks with high amount of silica. They are macroscopically recognizable by high percentage of quartz, K-feldspars and/or acidic plagioclases.
advancing glacier postupující ledovec (rostoucí) Glacier with a positive budget, so that accumulation results in the lower edges being pushed outward and downward.
Small earthquake that follows a main shock.
albite albit Kind of plagioclase (acidic) within the feldspar group with formula NaAlSi3O8. Its colour is light grey to grey. Other properties see feldspars.
aleurites aleurity Clastic sediments or sedimentary rocks with size of particles between 0,002-0,063 mm.
allothigenous minerals
Minerals, which were transported from other place into a newly formed sediment. These minerals are highly resistent to weathering processes.
allotriomorphic minerals alotriomorfně omezené minerály Minerals of igneous rocks which crystallize as latest in a process of magma crystallization. It results in a shape of these minerals, which are forced to crystallize in a space created by formerly crystallized sorrounding minerals.
alluvial deposits aluviální sedimenty General term for clastic sedimentary rocks with no cohesion, which have been transported and deposited by a stream.
alluvial fan aluviální kužel (dejekční) Large fan-shaped pile of sediment that usually forms where stream´s velocity decreases as it emerges from a narrow canyon onto a flat plain at the foot of a mountain range.
alpine glaciation alpínské zalednění Glaciation of a mountainous area.
amorphous substance amorfní látka Substance where atoms are not ordered in crystal lattice.
amphibole amfibol Ferromagnesian mafic mineral which belongs to silicates. Properties: black in colour, cleavaged, cleavage planes are stepped rather than smooth, splintery appearance, columnar, hardness is from 5 to 6, vitreous or silk luster.
amphibolite amfibolit Mostly black, amphibole (hornblende), plagioclase schist with characteristic plane parallel structure (compare with hornoblendite).
amygdaloidal structure mandlovcovitá textura Type of structure of igneous rocks, which is typical for its "almond shaped" pores secondary filled with material. This structure is formed after porous structure.
andesite andezit Fine-grained igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar with the rest being ferromagnesian minerals. It is often porphyritic.
angular ostrohranný Sharp-edged; lacking rounded edges or corners.
anhydrite anhydrit Anhydrite is a relatively common sedimentary mineral that forms massive rock layers. Anhydrite does not form directly, but is the result of the dewatering of the rock forming mineral Gypsum (CaSO4-2H2O). Color is ordinarily white, gray or colorless but also blue to violet. Luster is vitreous.Crystal habits include the tabular, rectangular box often elongated in one direction forming a prismatic crystal. Most commonly massive and granular. Cleavage is in three directions forming rectangles, but perfect in one, very good in another and only marginally good in the third direction. Hardness is 3.5.
anorthite anortit Mineral which belongs to plagioclase feldspar group with formula CaAl2Si2O8. Grey to dark grey in colour, other properties see feldspars.
anticline antiklinála An arched fold in which the rock layers usually dip away from the axis of the fold.
apatite apatit Hexagonal mineral with formula Ca5(PO4,CO3)3(F,OH,Cl). Green, green-brown, yellow in colour. Hardness is 5. Columnar shape. Poorly cleavaged.
aphanitic afanitický Pertaining to a texture of rocks in which the crystalline constituents are too small to be distinguished with the unaided eye. It includes both microcrystalline and cryptocrystalline textures.
aplite aplit A dike rock consisting almost entirely of light-coloured mineral constituents and having a characteristic fine-grained granitic texture.
aquifer zvodeň A body of saturated rock or sediment through which water can move readily.
arcose arkóza A sandstone in which more than 25% of the grains are feldspar.
artesian well artéská studna A well in which water rises above the aquifer.
asthenosphere astenosféra A region of the earth´s outer shell beneath the lithosphere. The asthenosphere is of indeterminate thickness and behaves plastically.
authigenous minerals autigenní minerály Minerals which occur on the place of their origin.
A ridge of sediment, usually sand or gravel, that has been deposited in the middle or along the banks of a stream by a decrease in stream velocity.
basal sliding
Movement in which the entire glacier slides along as a single body on its base over the underlying rock.
basalt čedič A fine-grained, mafic, igneous rock composed predominantly of ferromagnesian minerals and with lesser amount of calcium-rich plagioclase feldspar. Mostly black.
base level úroveň hloubky eroze A theoretical downward limit for stream erosion of the earth´s surface.
basic rocks bazické vyvřelé horniny Igneous rocks with relatively high percentage of mafic minerals and low percentage of silica (amount of SiO2 is between 44 and 52 %).
batholith batolit A large discordant pluton with an outcropping area greater than 100 square kilometers.
bedding zvrstvení An arrangement of layers or beds of rock.
bedding plane vrstevní plocha A nearly flat surface separating two beds of sedimentary rock.
bedrock skalní podklad Solid rock that underlies soil.
bentonite bentonit Rock composed of clay minerals, mainly montmorillonite, formed mostly by decomposition in water or weathering on the Earth surface.
biochemical sedimentary rocks biochemické sedimenty General term for organic and chemical sedimentary rocks.
biotite biotit Iron/magnesium bearing mica. Black to dark brown in colour, other properties see mica.
A depression on the land surface caused by wind erosion.
body waves
Seismic waves that travel through the earth´s interior.
bonding vazby Attachment of an atom to one or more adjacent atoms.
borelog záznam vrtného profilu Graphical report of a well.
boulder balvan A sediment particle with a diameter greater than 256 mm.
boulder loam souvková hlína Glacial sediment formed as a result of glacier accumulation, either in front of a glacier or on its base. It is mostly fine-grained material with larger fragments.
breccia brekcie A fragmental rock whose components are angular and therefore, as distinguished from conglomerates, are not waterworn.
butte svědecká hora A narrow pinnacle of resistant rock with a flat top and very steep sides.
calcite kalcit Mineral with the formula CaCO3. Mostly white, yellow or grey in colour, cleavaged, glassy luster on cleavage planes, hardness is 3, streak is always white. Reacts strongly with dilute hydrochloric acid.
Cambrian kambrium The oldest period in paleozoic, which took place 570-500 million of years ago.
canyon kaňon A long, deep valley with steep slopes, which was formed as a result of water stream erosion.
carbonates karbonáty A group of minerals, which have in their formulas CO3 anions. Properties of individual members of this group are very similar to calcite.
Carboniferous karbon A period in paleozoic (285-350 million of years ago), in which great amount of coal was formed.
cave jeskyně Naturally formed underground chamber.
caving sediments nezpevněné nesoudržné sedimenty Sedimentary rocks without cohesion.
cement pojivo The solid material that precipitates in the pore space of sediments, binding the grains together into a hard rock.
cementation zpevňování The process of chemical precipitation of material in the spaces between sediment grains, binding the grains together into a hard rock.
Cenozoic kenozoikum Geological period from Tertiary (65 million of years ago) to present.
cirque kar A steep-sided, amphitheater-like hollow carved into a mountain at the head of a glacial valley.
clastic sedimentary rocks klastické sedimentární horniny A sedimentary rocks composed of fragments of preexisting rocks, formed by weathering, transportation and deposition.
clastic textures klastické struktury An arrangement of rock fragments of different size of particles. This term can be used only for sedimentary rocks.
clay jíl Sediment composed of particles with diameter less than 0,002 mm.
clay minerals jílové minerály A hydrous-aluminium silicates that occurs as a platy grains of microscopic size with a sheet silicate structure (e.g. kaolinite, montmorillonite, illite, glauconite).
clay shale jílová břidlice Pelitic sedimentary rock, mostly laminated.
claystone jílovec Partly lithificated pelitic sediment.
cleavage štěpnost The ability of a mineral to break along preferred planes. It relates to inner structure of a mineral.
cleveage plane štěpná plocha Plane along which mineral with cleavage breaks.
cliff útes Steep, high rock on marine coast, which arose by water erosion.
coal uhlí A sedimentary rock formed by the consolidation of plant material. It is rich in carbon, usually black, and burns readily.
coarse-grained rock hrubě zrnitá hornina Rock in which most of the grains are from 3 to 10 mm in size.
cobble valoun A sediment particle with a diameter of 64 to 256 mm.
coefficient of flatness koeficient plochosti Ratio between the longest and the shortest axis of rock fragment.
columnar shape sloupcovitý tvar 1. Shape formed by jointing of some volcanic rocks - parallel, usually vertical columns, mostly six-sided. 2. Habitus of some minerals.
compact structure kompaktní textura Type of structure of rocks, where there are no pores in a rock.
compaction kompakce A loss in overall volume and pore space of a rock as a particles are packed closer together by the weight of overlying material.
concordant konkordantní Parallel to layering or earlier developed planar structures.
cone of depression depresní kužel A depression of the water table formed around a well when water is pumped out; it is shaped like an inverted cone.
confined aquifer napjatá zvodeň An aquifer completely filled with pressurized water and separated from the land surface by a relatively impermeable confining bed, such as shale.
confining pressure všesměrný tlak Pressure applied equally on all surfaces of a body; also called geostatic or lithostatic pressure.
conglomerate slepenec A coarse-grained sedimentary rock (grains coarser than 2 mm) formed by the cementation of rounded gravel.
conchoidal fracture lasturnatý lom Type of fracture similar to conch surface.
contact metamorphism kontaktní metamorfóza Metamorphism under conditions in which high temperature is the dominant factor.
contact schist kontaktní břidlice Metamorphic rock formed usually on a contact between magma and sedimentary pelitic rock.
contact-metamorphic rocks kontaktně metamorfované horniny Metamorphic rocks formed as a result of contact between magma and some rock. This type of metamorphism is mostly thermal.
continental crust kontinentální zemská kůra A part of the Earth´s crust which forms continents. It´s thickness is from 25 km to 80 km, 38 km in average. The thickness of continental crust and its structure varies according to geological units. Young alpine mountain belts have continental crust up to 80 km thick (Himalayas).
continental drift kontinentální drift A concept suggesting that continents move over the earth´s surface.
continental glaciation kontinentální zalednění The covering of a large region of a continent by a sheet of glacial ice.
continental shelf kontinentální šelf A submarine platform at the edge of a continent, inclined very gently seaward generally at an angle of less than 1!. It is bordered by continental slope.
continental slope kontinentální svah A relatively steep slope extending from a depth of 100 to 200 meters at the edge of the continental shelf down to oceanic depths.
convection konvekční proudění A very slow circulation of a substance driven by differences in temperature and density within that substance.
converging boundary konvergentní rozhraní Boundary between two lithospheric plates that are moving toward each other.
coquina organodetritický vápenec A limestone consisting of large shells.
coral reefs korálové útesy Organogenous rocks on marine coast composed of coral skeletons.
core zemské jádro The central zone of the earth. It´s radius is 3478 km.
correlation korelace Determining age relationships between rock units or geologic events in separate areas.
craton kraton Portion of a continent that has been structurally stable for a prolonged period of time.
creep plouživý pohyb Very slow, continuous downslope movement of soil and rock.
Cretaceous křída The last period of Mesozoic before Tertiary (136-65 millions of year ago).
crevasses ledovcová trhlina Open fissures in a glacier.
cross bedding křížové zvrstvení An arrangement of relatively thin layers of rock inclined at an angle to the more nearly horizontal bedding planes of the larger rock unit.
crust zemská kůra The outer layer of rock, forming a thin skin over the earth´s surface.
crust fault hlubinný zlom Very deep fault (from tenths to hundreds of kilometers) in the Earth´s crust, which separates two litospheric plates.
crustal rebound
The rise of the earth´s crust after the removal of glacial ice.
crystalline substance krystalická hmota Substance with specific inner structure, which is called crystal lattice.
crystalline texture krystalická struktura An arrangement of interlocking crystals.
Darcy´s law Darcyho zákon Formula, in which relation between hydraulic gradient, hydraulic conductivity and soak velocity is defined.
debris suť Any unconsolidated material at the earth´s surface.
debris avalanche bahnotok A very rapidly moving, turbulent mass of debris, air and water. This is the fastest variety of debris flow.
deflation deflace The removal of clay, silt and sand particles from the land surface by wind.
delta delta A body of sediment deposited at the mouth of a river when the river velocity decreases as it flows into a standing body of water.
denudation denudace General term for lowering of the earth surface by processes such as erosion etc.
deposition usazováni The settling or coming to rest of transported material.
depth of focus hypocentrum zemětřesení Distance between the focus and the epicenter of an earthquake (perpendicular distance between the focus and the Earth surface).
desert poušť A region with low precipitation (usually defined as less than 25 cm per year)
Devonian devon Period of Paleozoic (between 395-345 million of years ago).
diabase diabas A rock of basaltic composition, consisting essentially of labradorite and pyroxene,and characterized by ophitic texture (discrete crystals or grains of pyroxene fill the interstices between lath-shaped feldspar crystals).
diamond diamant Mineral which is composed of carbon, the hardest mineral on the Earth (hardness=10). It was formed in conditions of high pressure and temperature.
diatomite diatomit Organogenous sediment composed mostly of very small silica shells (shells of organisms called Diatomacea)
dike pravá žíla A tabular, discordant intrusive structure.
diorite diorit Plutonic igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar and the rest is ferromagnesian minerals.
dip sklon The angle that a structural surface, e.g. a bedding or fault plane, makes with a horizontal. See dip angle, direction of dip.
dip angle úhel sklonu A vertical angle measured downward from the horizontal plane to an inclined plane.
dip-slip fault
A fault in which movement is parallel to the dip of the fault surface.
direction of dip směr sklonu The compass direction in which the angle of dip is measured.
disappearing stream ponor Surface stream, which apparently disappears under ground and appears again on a surface at different place. This type of stream is common in area with limestones (karst).
discordant diskordantní Not parallel to any layering or parallel planes.
diverging boundary divergentní rozhraní Boundary separating two lithospheric plates moving away from each other.
dolomite dolomit 1. Type of mineral with formula (Ca,Mg)(CO3)2. It´s properties are very similar to calcite, but it reacts slowly with dilute hydrochloric acid unless powdered. 2. A sedimentary rock composed mostly of the mineral dolomite.
Dolostone dolomit Synonym for dolomite.
downcutting hloubková eroze A valley-deepening process caused by erosion of a stream bed.
drainage odvodnění Removal of water from some area by system of channels, ditches or drainage wells.
The lowering of the water table near a pumped well.
drilling vrtání Making of a vertical round shaped hole under the surface for different purpose - for example obtain a underground water or to obtain some information about geologic conditions.
drumlin drumlin A long, streamlined hill made of till.
dry stream bed vyschlé koryto řeky Stream bed, which is temporary without water.
dull luster matný lesk
earthflow sesuv Slow-to- rapid mass wasting in which debris moves downslope as a very viscous fluid (See landslide).
earthquake zemětřesení A trembling or shaking of the ground caused by the sudden release of energy stored in the rocks beneath the surface.
eclogite eklogit Basic metamorphic rock consisting mainly from minerals garnet and pyroxene (omphacite). Mostly dark grey to black in colour with massive structure.
effusive rocks výlevné horniny Igneous rocks which have solidified on the earth surface.
end moraine čelní moréna A ridge of till piled up along the front edge of a glacier.
environment of deposition sedimentační prostředí The location in which deposition occurs, usually marked by charakteristic physical, chemical or biological conditions.
epicenter epicentrum zemětřesení The point on the earth´s surface directly above the focus of an earthquake.
epidote epidot It occurs sometimes in form of finely crystalline masses in joints of a rock, rarely forms elongate crystals. Color is "pistachio" green to yellowish or brownish green, also brown to black. Hardness is more than 5, cleavaged.
erlan erlan Contact metamorphic rock consisting mainly of calcium silicates.
erosion eroze The physical removal of rock by an agent such as running water, glacial ice, or wind.
erratic eratický balvan An ice-transported boulder that does not derive from bedrock near its present site.
esker esker A long, sinuous ridge of sediment deposited by glacial meltwater.
essential minerals hlavní (podstatné) horninotvorné minerály Rock forming minerals, which form essential part of a rock. They are important for classification of a rock.
evaporites evapority Sedimentary rocks that form from crystals precipitating during evaporation of water.
even-grained texture stejnoměrně zrnitá struktura Type of texture of igneous rocks, where minerals in a rock are not very different in size (opposite term to porphyritic structure).
exfoliation exfoliace The stripping of concentric rock scales to slabs from the outer surface of a rock mass.
extrusive rocks výlevné vyvřelé horniny Any igneous rocks that form at the earth´s surface, whether it soldifies directly from a lava flow or is pyroclastic.
fall skalní řícení The situation in mass wasting that occurs when material free-falls or bounces down a cliff. See rockfall.
fault zlom A fracture in bedrock along which movement has taken place.
feldspars živce Group of most common minerals of the earth´s crust. All feldspars contain silicon, aluminium, and oxygen and may contain potassium, calcium, and sodium. Pink, white to dark grey, rarely green in colour. Hardness is around 6. Perfect cleavage, vitreous luster when fresh, dull when weathered. Attention: According to luster on cleavage planes are feldspars very often confused with muscovite.
felsic rocks světlé vyvřelé horniny Silica rich igneous rocks with silica content more then 65%.
fine-grained rocks jemnozrnné horniny A rocks (except clastic sediments) in which most of the mineral grains are between 0,33-0,01 mm in size.
fiord fjord A coastal inlet that is a glacially carved valley, the base of which is submerged.
firn firn A compacted mass of granular snow, transitional between snow and glacial ice.
fissured clays potrhané jíly Clays with a lot of small, irregular fissures.
flexure ohyb Bending of beds (without rupture) as a result of long lasting and slow tectonic pressure.
flint pazourek A dense, fine-grained form of silica which is very tough and breaks with a conchoidal fracture and cutting edges. It occurs in cretaceous cliffs.
flood erosion
Erosion caused by the high velocity and large volume of water in a flood.
flood plain inundační území A broad strip of land built up by sedimentation on either side of a stream channel.
flow tečení A type of movement that implies that a descending mass is moving downslope as a viscous fluid.
fluidal structure proudovitá textura Structure of igneous rocks, where rock particles have preferred direction in orientation.
fluorite fluorit Mineral with formula CaF2. It is a basic raw material for fluor and fourth member of Moh´s scale. Purple, green, yellow in colour. Perfect cleavage, vitreous luster.
focus ohnisko zemětřesení (hypocentrum) The point within the earth from which seismic waves originate in an earthquake.
foids zástupci živců Group of minerals formed instead of feldspars within the process of magma crystallization, when amount of SiO2 in magma is reduced. Main members of this group are: leucite, nepheline, analcime, sodalite, nosean, hauyne.
fold vrása Bend in layered bedrock of sinusoidal shape.
foliation foliace Parallel alignment of structural features of a rock.
foliation plane foliační plocha Plane with parallel alignment to structural features of a rock.
fossiliferous limestone organogenní vápenec Limestone composed of fossil shells or skeletons.
fossils fosílie Traces or fragments of skeletons of plants or animals preserved in rock.
fracture zlom The way a substance breaks where not controlled by cleavage.
fracture plane lomná plocha Curved plane formed by fracture, often conchoidal.
fragments of rocks úlomky hornin Pieces of rock decoposed by mechanical or chemical weathering.
fresh rock nezvětralá hornina Rock not affected by weathering.
frost action účinek mrazu Mechanical weathering of rock by expanzion of freezing water.
frost heaving
The lifting of rock or soil by the expansion of freezing water.
frost wedging
A type of frost action in which the expansion of freezing water pries a rock apart.
gabbro gabro A mafic, coarse-grained igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
gaining stream
A stream that receives water from the zone of saturation.
garnet granát Reddish brown, yellowish tan in clolour, vitreous to pitch luster. Hardness is 6.5 to 7.5. Without cleavage. Mineral which often occurs in metamorphic rocks, sometimes in igneous rocks.
geologic cross-section geologický řez A representation of a portion of the earth in a vertical plane.
geologic time scale geologická časová škála Geologic term, which means mirroring of Earth history expressed in a form of geologic periods.
geology geologie Scientific branch studying origin and development of the Earth and other planets.
geophysics geofyzika The application of physical laws and principles to a study of the earth.
geothermal energy geotermální energie Thermal energy produced by the Earth. Some sources of this energy can be harnessed and used by a man.
geothermal gradient geotermální gradient Rate of temperature increase associated with increasing depth beneath the surface of the earth (normally about 25!C/km).
geyser gejzír A type of hot spring that periodically erupts hot water and steam.
geyserite gejzírit A deposit of silica that forms around many geysers and hot springs.
glacial age doba ledová Geologic period in Quaternary, when glaciers were advancing.
glacial budget
Sum of advancing and receding of glacier per one year (positive and negative).
glaciation zalednění General term for covering of the Earth surface by a glacier.
glacier ledovec A large, long-lasting mass of ice, formed on land by the compaction and recrystallization of snow, which moves because of its own weight.
glacier recession ústup ledovce Receding of a glacier.
glacier tonque splaz ledovce "Freezing stream shaped" accumulation of ice on edge of a glacier.
glassy luster skelný lesk A luster that gives a substance a glazed, porcelainlike appearance. See vitreous luster.
glauconite glaukonit Dark green coloured clay mineral occuring in some sands and sandstones. Properties see clay minerals.
gneiss rula A metamorphic rock composed prevailingly of quartz, feldspars and micas arranged in plane parallel structure.
graben příkopová propadlina A down-dropped block bounded by normal faults.
graded bed
A single bed with coarse grains at the bottom of the bed and progressively finer grains toward the top of the bed.
graded bedding gradační zvrstvení An arrangement of layers of clastic sediments and sedimentary rocks. Each layer has different size of particles and granularity of layers tends topward from coarse to fine.
granite granit A felsic, coarse-grained, intrusive igneous rock composed mostly of quartz, feldspars and often containing micas. It belongs to group of granitoids.
granite porphyr žulový porfyr Dike rock with composition similar to granite. It differs only by a texture and structure.
granitoids granitoidy A group of "granite like rocks", which differs from each other only by type of feldspar.
granoblastic texture granoblastická struktura Texture of metamorphic rocks, which is characterized by "grain shaped" minerals, e.g. marble.
granodiorite granodiorit Igneous plutonic rock belonging to group of granitoids. It has composition similar to granite except the ratio between types of feldspar (plagioclases>K-feldspars).
granulite granulit High-grade metamorphic rock, ligh-grey coloured. It is composed of quartz and feldspars, mostly with presence of small garnet grains.
graphic texture písmenková struktura Special texture created by intergrowth of feldspars and quartz, which looks like hieroglyfic letters.
graphite grafit Mineral formed of carbon. Gray to black in colour. Hardness is 1. It may have dull luster, greasy feel, soils paper and fingers.
gravel štěrk Sediment composed of rounded particles coarser than 2 mm in diameter.
greywacke droba A sandstone with more than 20% of unstable particles and feldspars within psammitic fraction and more then 15% of finegrained matrix.
ground moraine spodní (bazální) moréna A blanket of till deposited under a glacier or released as glacier ice melted.
groundmass základní hmota The material between the phenocrysts in porphyritic igneous rock. It includes the basis or base as well as the smaller crystals of the rock. Essentially synonymous with matrix.
groundwater podzemní voda The water that lies beneath the ground surface, filling the cracks, crevices, and pore space of rocks.
gypsum sádrovec Mineral with formula CaSO4. It is formed by evaporation. Clear, white, light grey in colour. Hardness is 2. Vitreous to pearly luster, brittle sheets. Perfect cleavage.
habit habitus Term describing shape of a crystal (e.g. tabular, columnar).
halite sůl kamenná Mineral with formula NaCl. It is formed by evaporation. Clear to grey in colour. Hardness is 2.5. Perfect cleavage. Salty taste.
hanging valley visuté údolí A smaller valley that terminates abruptly high above a main valley.
headward erosion zpětná eroze The lenghtening of a valley in an uphill direction above its original source by gullying, mass wasting, and sheet erosion.
hematite hematit (1) Mineral with formula Fe2O3. Mostly fine grained, reddish brown in colour. Hardness is 1.5 to 5.5, dull luster. It occurs in form of earthy masses. It is product of chemical weathering (oxidation). (2) Rarely with formula Fe3O4, steel grey to dull red in colour. Hardness is 6. May be micaceous (tiny flakes) or massive.
hemicrystalline rocks hemikrystalické horniny Volcanic rocks, which have cooled very quickly. Part of rock mass is composed of volcanic glass.
hinge line osa vrásy Line about which a fold appears to be hinged. Line of maximum curvature of a folded surface.
hinge plane rovina vrásy See axial plane.
holocrystalline rocks holokrystalické horniny Igneous rocks with fully crystalized rock mass.
horizontal bedding horizontální zvrstvení Type of bedding, where layers are oriented horizontally.
hornblende obecný amfibol Common amphibole frequently found in igneous and metamorphic rocks. Properties see amphibole.
hornfels kontaktní rohovec A fine-grained, unfoliated metamorphic rock.
horst hrásť An up-raised block bounded by normal faults.
hyaline texture hyalinní struktura Texture of volcanic rocks or their groundmass, which is formed by amorphous substance.
hydraulic conductivity koeficient filtrace Number characterizing permeability of rocks.
hydraulic gradient hydraulický gradient The ratio between vertical difference of heights of two water tables and their horizontal distance.
hydrologic cycle hydrologický cyklus The movement of water and water vapor to the atmosphere, to the land, and to the atmosphere again.
hypidiomorphic minerals hypidiomorfně omezené minerály Partly confined mineral grains formed during crystallization of magma.
hypocenter hypocentrum zemětřesení Synonym for the focus of an earthquake.
chalk křída A very fine-grained bioclastic limestone, which often forms high white cliffs on the coast.
chalkopyrite chalkopyrit Metallic mineral with formula CuFeS2. Golden yellow or greenish yellow in colour. Hardness is 3.5 to 4. Massive.
chemical sedimentary rocks chemické sedimentární horniny A sedimentary rocks composed of material precipitated directly from solution.
chemical weathering chemické zvětrávání The decomposition of rock resulting from exposure to water and atmospheric gases.
chert rohovec A hard, compact, fine-grained sedimentary rock formed almost entirely of silica.
chlorite chlorit Mineral belonging to mica group formed mostly during metamorphism. It can be also formed by alteration processes. Green to blackish green in colour. Dull to pearly luster. Hardness 2 to 2.5. May have faint green-yellow streak. Crystal flakes are flexible but not elastic. Finely crystalline aggregates common.
ice cap ledovcová čapka A glacier covering a relatively small area of land but not restricted to a valley.
ice sheet kontinentální ledovec A glacier covering a large area (more than 50 000 square kilometers) of land.
iceberg ledovec Block of glacier-derived ice floating in water.
idiomorphic minerals idiomorfně omezené minerály Completely confined mineral grains formed during crystallization of magma.
igneous rocks vyvřelé horniny A rocks formed or apparently formed from solidification of magma.
illite illit Non-swelling type of clay mineral. Properties see clay minerals.
inner core vnitřní jádro The most inner part of the Earth.
intermediate igneous rocks intermediární vyvřelé horniny Igneous rocks with a chemical content between felsic and mafic compositions.
intrusive bodies intruzívní tělesa Bodies formed by magma crystallization under the earth surface.
intrusive rocks intruzivní horniny Rocks that appears to have crystallized from magma emplaced in surrounding rock.
isoclinal fold izoklinální vrása A fold in which the limbs are parallel to one another.
isostasy izostáze The balance or equilibrium between adjacent blocks of crust resting on a plastic mantle.
isostatic adjustment izostatické vyrovnání Concept of vertical movement of sections of the earth´s crust to achieve balance or equilibrium.
izometric shape izometrický tvar Term describing ball-like shape of mineral grains.
joint prasklina, trhlina A fracture or crack in bedrock along which essentially no displacement has occured.
Jurassic jura A period in Mesozoic (145-195 million of years ago).
K-feldspars draselné živce Subgroup of feldspars containing potassium in the structure (KAlSi3O8). Properties see feldspars.
kaolin kaolin Sediment composed mostly of clay mineral kaolinite. It was formed as a residual rock by processes of chemical weathering.
kaolinite kaolinit Non-swelling member of clay mineral group. Properties see clay minerals.
karst kras An area formed mostly of limestones with many sinkholes and a cave system beneath the land surface, usually lacking a surface stream.
kinetic metamorphism dislokační metamorfóza Special type of metamorphism caused by tectonic forces in a fold zone.
kyanite kyanit Mineral with formula Al2SiO5 formed during metamorphism. Light blue to greenish blue in colour, cleavaged. Hardness is 5 parallel to long direction of crystal and 7 across crystal. It forms blade-shaped crystals and has vitreous luster.
labradorite labradorit Member of plagioclase subgroup with special optical effects (it reflects daylight as blue in some slices). Properties see feldspars.
lamination laminace The layering or bedding less than 1 cm in thickness in a sediment or a sedimentary rock.
landslide sesuv The general term for a slowly to very rapidly descending rock or debris (see earthflow).
lateral erosion boční eroze Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
lateral moraine boční moréna A low ridgelike pile of till along a side of a glacier.
lava láva Magma on the earth's surface. Fluid rock such as that which issues from a volcano or a fissure in the earth's surface.
lava flow lávový proud Long, narrow stream of lava flowing downhill from a volcano.
lava sheet lávový příkrov Wide-spreaded sheet of lava covering large area around a volcano.
lepidoblastic texture lepidoblastická struktura Type of metamorphic texture formed mostly of scaled minerals.
limb rameno vrásy Portion of a fold shared by an anticline and a syncline.
limestone vápenec A sedimentary rock composed mostly of calcite.
limonite limonit Limonite (Fe2O3.nH2O). is a general name for several rust-like hydrous iron oxides. It usually forms rust-like coatings on rocks. Yellow-brown, orange-brown to dark brown in colour.
lithification zpevňování (diageneze) The consolidation of sediment into sedimentary rock.
litosphere litosféra The rigid outer shell of the earth, 70 to 125 or more kilometers thick.
local metamorphic rocks lokálni metamorfované horniny Rocks produced by local metamorphism.
local metamorphism lokální metamorfóza Metamorphism involving relatively high temperature or pressure which affects small area.
loess spraš A fine-grained deposit of wind-blown dust containing CaCO3 often in the form of "nodules".
loessloam sprašová hlína Eolic sediment formed by leaching of CaCO3 from loess.
losing stream
Stream that loses water to the zone of saturation.
lower mantle spodní plášť One of the inner shells of the earth.
luster lesk The quality and intensity of light reflected from the surface of a mineral.
macroscopically dense makroskopicky celistvý Type of rock texture (according to absolute size of grains) with macroscopically non-visible grains.
mafic rocks tmavé vyvřelé horniny Igneous rocks with low amount of silica. They are composed mostly of Fe, Mg rock-forming minerals.
magma magma Molten rock, usually mostly silica. It may contain dissolved gases as well as some solid minerals.
magma chamber magmatický krb Huge body of magma situated beneath the surface where magma is accumulated.
magnitude magnitudo zemětřesení A measure of the energy released during an earthquake.
mantle zemský plášť A thick shell of rock that separates the earth's crust above from the core below.
marble mramor A fine- or coarse-grained metamorphic rock composed of interlocking calcite (or dolomite) crystals.
marl slín Clay with high amount of CaCO3 (25-75%).
marl slate slínitá břidlice Clayshale with high amount of CaCO3 (25-75%).
marlite slínovec Partly lithificated pelitic sediment with significant amount of CaCO3 (25-75%).
mass movement svahový pohyb Movement, caused by gravity, in which bedrock, rock debris, or soil moves downslopein bulk.
mass wasting svahový pohyb Equivalent term to mass movement.
massive structure všesměrně zrnitá textura Structure without stratification, flow-banding, foliation, schistosity, etc.
matrix základní hmota Fine-grained material found in the intergranular space between larger grains of sedimentary rocks.
meander meandr A pronounced sinuous curve along a stream's course.
meander cutoff
A new, shorter channel across the narrow neck of a meander.
medial moraine střední moréna A single long ridge of till on a glacier, formed by adjacent lateral moraines joining and being carried downglacier.
medium-grained rock středně zrnitá hornina Rock in which most of the grains are from 1 to 2 mm in size.
mechanical weathering mechanické zvětrávání The physical disintegration of rock into smaller pieces.
melaphyre melafyr Volcanic rock, formerly porous Mesozoic basalt where pores were secondary filled with other minerals. Its typical structure is amygdaloidal.
mesa tabulová hora A broad, flat-topped hill bounded by cliffs and capped with a resistant rock layer.
mesh structure okatá textura Structure of some metamorphic rocks composed of ellipsoidal mineral grains.
Mesozoic mesozoický Geological era that followed the Paleozoic Era and preceded the Cenozoic Era (from 225 to 65 mil. of years ago).
metallic luster kovový lesk Luster giving a substance the appearance of being made of metal.
metamorphic rocks metamorfované horniny Rocks produced by metamorphism.
metamorphism metamorfóza The transformation of preexisting rock into structurally or mineralogically distinct new rock as a result of high temperature, high pressure, or both, but without the rock melting process.
metaquarcite metakvarcit Metamorphic rock composed mostly of quartz with micas on foliation planes.
metaquartzite metakvarcit A rock composed of sand-sized grains of quartz that have been welded together during metamorphism.
micas slídy Group of minerals belonging to sheet-silicates with variable size of grains and colour. Significant properties are: hardness 2.5, perfect cleavage, glassy to pearl luster and elasticity of scales.
mid-oceanic ridge stoedooceánský hobet A giant mountain range that lies under the ocean and extends around the world.
migmatite migmatit Mixed igneous and metamorphic rockwith typical migmatitic structures.
mineral minerál A naturally occuring, inorganic, homogenous, crystalline or amorphous mostly solid that has a definite chemical composition.
mineral content minerální slo?ení Term describing composition of a rock.
mineral hardness tvrdost minerálu The relative easy or difficulty with which a smooth surface of a mineral can be scratched; commonly measured by Mohs' scale.
modified Mercali scale modifikovaná Mercaliho škála Scale expressing intensities of earthquakes (judged on amount of damage done) in Roman numerals ranging from I to XII.
Moh´s scale of hardness Mohrova stupnice tvrdosti Scale on which ten minerals are designated as standards of hardness.
Mohorovieie diskontinuity Mohorovieieova diskontinuita The boundary separating the crust from the mantle beneath it (also called Moho).
monomict monomiktní Within the psefitic, clastic sedimentary rocks, formed from one type of fragments.
montmorillonite montmorillonit Swelling type of clay mineral. Properties see clay minerals.
moraine moréna A body of till either being carried on a glacier or left behind after a glacier has receded.
mud bahno Term loosely used for silt and clay, usually wet.
mudcracks bahenní praskliny Polygonal cracks formed in very fine-grained sediment as it dries.
mudflow bahnotok A flowing mixture of debris and water, usually moving down a channel.
mudpot bahenní sopka Specific type of hot spring that contains thick, boiling mud.
mudstone slínovec A fine-grained sedimentary rock that lacks shale's laminations and fissility.
muscovite muskovit Transparent or white mica that lacks iron and magnesium. Properties see micas.
nacreous luster perle?ový lesk See pearly luster.
natural glass vulkanické sklo Amorphous form of silica formed by very fast cooling of lava.
nematoblastic texture nematoblastická struktura Metamorphic texture formed mostly of columnar or spicular minerals.
Neogene neogenní Younger epoch of Tertiary period (from 1.8 to 25 mil. of years ago).
oblique-slip fault
A fault with both strike-slip and dip-slip components.
obsidian obsidian Volcanic glass black in colour with typical conchoidal fracture.
oceanic crust oceánská kura The thin, basaltic crust under oceans.
oceanic trench hlubokomooský poíkop A narrow, deep through parallel to the edge of a continent or an island arc.
olivine olivín A ferromagnesian mineral with the formula (Fe, Mg)2SiO4. Yellowish green to green in colour, conchoidal fracture but not obvious cleavage, with vitreous luster. Hardness is 6.5 to 7. Most olivine occurs in a form of accumulations of small crystals in dark-coloured igneous rocks (e.g. basalt).
oolitic limestone oolitický vápenec A limestone formed from a small spheres of calcite precipitated from seawater.
open fold otevoená vrása A fold with gently dipping limbs (angle between limbs 70-120).
orbicular structure kulovitá textura Special type of structure of plutonic rocks where feldspars are in concentric arrangement.
Ordovician ordovický Period in lower Paleozoic (from 435 to 500 mil. of years ago).
ore ruda Naturally occuring material that can be profitably mined.
organic sedimentary rocks organogenní sedimentární horniny Rocks composed mostly of the remains of plants and animals.
organic sediments organogenní sediment Sediments composed mostly of the remains of plants and animals.
orogeny orogen An episode of intense deformation of the rocks in a region, generally accompanied by metamorphism and plutonic activity.
orthoclase ortoklas A potassium feldspar with the formula KAlSi3O8. Properties see feldspars.
orthogneiss ortorula Type of gneiss formed from igneous rocks.
outcrop výchoz A surface exposure of bare rock, not covered by soil or vegetation.
outer core vnijší jádro A thick shell of rock between inner core and lower mantle.
overturned fold poekocená vrása A fold in which both limbs dip approximatelly in the same direction.
oxbow lake slepé rameno A crescent-shaped lake occupying the abandoned channel of a stream meander that is isolated from the present channel by a meander cutoff and sedimentation.
P-waves p-vlny Compressional waves (seismic waves) in which rock vibrates parallel to the direction of wave propagation.
Paleogene paleogen Older epoch of Tertiary period (from 23.7 to 66.4 mil. of years ago).
Paleozoic paleozoikum Geological era that followed the Precambrian and during which began with the appearance of complex life, as indicated by fossils (from 245 to 570 mil. of years ago).
paragneiss pararula Type of gneiss formed from sedimentary rocks.
parent rock mateená hornina Original rock before being metamorphosed.
pearly luster perle?ový lesk A luster that gives a substance pearly appearance.
pebble oblázek A sediment particle with a diameter of 2 to 64 mm.
pegmatite pegmatit Extremely coarse-grained igneous rock formed mainly of feldspars and quartz together with micas and other minerals. It has zonal structure. In czech classification it belongs to dike rocks, in english classification to plutonic rocks.
pelagic sediment pelagické sediment Sediment made up of fine-grained clay and skeletons of microscopic organisms that settle slowly down through the ocean water to the sea bottom.
pelites pelity Within the clastic subgroup of sediments and sedimentary rocks the most fine-grained category (<0.002 mm).
pencil structure stébelnatá textura Rare type of structure of metamorphic rocks characterized by mineral grains which are extremly elongated along one axis and arranged in linear parallel structure.
perlite perlit Type of volcanic glass. It seems to be composed of many small particles "pearls".
permeability permeabilita The capacity of a rock to transmit a fluids (liquids or gases).
Permian perm The youngest period of Paleozoic (from 245 to 286 mil. of years ago).
phaneritic faneritický A textural term applied to igneous rocks in which all the crystals of the essential minerals can be distinguished with the unaided eye. The adjective form phaneritic is currently used more frequently than the noun.
phenocryst porfyrická vyrostlice Any of the large crystals in porphyritic igneous rock.
phonolite znilec (fonolit) Type of rock composed of feldspars, foids, pyroxenes and amphiboles.
phthanite buli?nik Biochemical sedimentary rock, mostly black in colour, composed of silica.
phyllite fylit A metamorphic rock in which clay minerals have recrystallized into microscopic micas, giving the rock a silky sheen.
pitch luster smolný lesk A luster that gives a substance pitch appearance.
pitchstone smolek Type of volcanic glass with typical pitch luster.
plagioclases sodnovápenaté ?ivce Subgroup of feldspars containing sodium and/or calcium in addition to aluminium, silicon, and oxygen. Properties see feldspars.
plate tectonics desková tektonika A theory that the earth's surface is divided into a few large, thick plates that are slowly moving and changing in size. Intense geologic activity occurs at the plate boundaries.
plateau náhorní rovina Broad, flat-topped area elevated above the surrounding land and bounded, at least in part, by cliffs.
plunging fold vrása A fold in which the hinge line (or axis) is not horizontal.
pluton pluton An igneous body that crystallized deep underground.
plutonic rocks hlubinné horniny Igneous rocks formed at great depth.
polar wandering migrace pólu An apparent movement of the earth's poles.
polymict polymiktni(valouny více druhu) Within psefitic sediments or sedimentary rocks, term describing composition of many types of fragments.
porcelanite porcelanit Metamorphic rock with typical conchoidal fracture and sharp edges which was formed by contact metamorphism of pelitic sediments.
pore space intergranulární prostor The total amount of space taken up by openings between sediment grains.
porosity pórosita The percentage of a rock's volume that is taken up by openings.
porous structure pórovitá textura Structure of a rock where part of rock volume is taken up by openings.
porphyritic texture porfyrická struktura Texture of those igneous rocks in which larger crystals (phenocrysts) are set in a finer groundmass which may be crystalline or glassy, or both.
porphyroblastic texture porfyroblastická struktura Texture of metamorphic rocks very similar to porphyritic texture of igneous rocks (groundmass cannot be glassy).
potassium feldspar draselný ?ivec A feldspar with the formula KAlSi3O8.
Precambrian time prekambrium The vast amount of time that preceded the Paleozoic Era (before 570 mil. of years).
psammites psamity Clastic sediments or sedimentary rocks with sizes of particles between 0.06 and 2 mm.
psefites psefity Clastic sediments or sedimentary rocks with size of particles over 2 mm.
pyrite pyrit Mineral with formula FeS2 with "gold" appearance. It is sometimes present as accessory mineral in igneous rocks.
pyroclastic rocks pyroklastika Rocks formed by lithification of pyroclasts.
pyroclasts pyroklastika Fragments of rocks formed by volcanic explosion.
pyroxene pyroxen Ferromagnesian mafic mineral which belongs to silicates. Black to dark-green in colour, vitreous to dull luster. Hardness is from 5 to 6. It has two imperfect cleavages meet at nearly 90 degrees (it is not often macroscopically visible). Shape is usually short columnar.
quarry lom An open or surface working, usually for the extraction of building stone, as slate, limestone, etc. In its widest sense the term mines includes quarries, and has been sometimes so construed by the courts; but when the distinction is drawn, mine denotes underground workings and quarry denotes superficial workings.
quartz koemen Mineral with the formula SiO2. In the nature it occurs in many different colours, but as a rock forming mineral it is usually light grey or grey in colour. Hardness is 7, usually forms allotriomorphic grains.They are macroscopically recognizable from feldspars by fracture planes with vitreous luster (no cleavage planes).
quartz diorite koemenný diorit Plutonic rock belonging to granitoid group, where plagioclases prevail over K-feldspars.
quartzite koemenec A quartz rock derived from sandstone, composed dominantly of quartz, and characterized by such thorough induration, either through cementation with silica or through recrystallization, that it is essentially homogeneous and breaks with vitreous surfaces that transect original grains and matrix or interstitial material with approximatelly equal ease.
Quaternary kvartér The youngest geological period; includes the present time (from 1.8 mil. of years ago to present).
receding glacier ustupující ledovec (zmenšující se) A glacier with a negative budget, which causes the glacier to grow smaller as its edges melt back.
Recent recentní (soueasný) Formed in the present time.
recumbent fold le?atá vrása A fold overturned to such an extent that the limbs are essentially horizontal.
regional metamorphic rocks regionálni metamorfované horniny Type of metamorphic rocks formed by the proces of regional metamorphism.
regional metamorphism regionální metamorfóza Metamorphism involving relatively high temperature and pressure which affects large areas.
The addition of new water to an aquifer or to the zone of saturation.
residual rocks reziduální horniny Remaining part of parent rock after weathering which was not transported. It is often fragmented and caving.
resinous luster smolný lesk See pitch luster.
reverse fault poesmyk A fault in which the hanging-wall block moved up relative to the footwall block.
rhyolite ryolit A fine-grained, felsic, volcanic igneous rock made up mostly of feldspar and quartz. Often with porous and fluidal structure.
rift valley riftové údolí A tensional valley bounded by normal faults. Rift valleys are found at diverging plate boundaries on continents and along the crest of the mid-oceanic ridge.
rigid zone
Upper part of a glacier in which there is no plastic flow.
Richter scale Richterova stupnice A numerical scale of earthquake magnitudes.
ripple marks eeoiny Small ridges formed on sediment surfaces exposed to moving wind or water. The ridges form perpendicularly to the motion.
rock hornina Rock is inhomogeneous mineral association which forms the earth's crust in a form of many separated units. Every rock is characterized by structure, texture and mineral coposition reflecting its origin.
rock avalanche
A very rapidly moving, turbulent mass of broken-up bedrock.
rock forming minerals horninotvorne mineraly Group of minerals that form greatest part of rock volume.
rock strength pevnost horniny Ability of rock to resist to surrounding pressure.
rockfall skalní oícení Rock falling freely or bouncing down a cliff.
rounding zaoblení The grinding away of sharp edges and corners of rock fragments during transportation.
rupture koehká deformace Brittle deformation of rock.
S-waves S-vlny A seismic waves propagated by a shearing motion, which causes rock to vibrate perpendicular to the direction of wave propagation.
sand písek Sediment composed of particles with a diameter between 2 mm and 0.06 mm.
sand dune píseené duny A mound of loose sand grains heaped up by the wind.
sandstone piskovec A medium-grained sedimentary rock (grains between 2 mm and 0.06 mm) formed by the cementation of sand grains (mainly quartz).
saturated zone nasycená zóna A subsurface zone in which all rock openings are filled with water.
scaled shape šupinkovity Sheet-like mineral shape (e.g. micas).
sea-floor spreading
The concept that the ocean floor is moving away from the mid-oceanic ridge and across the deep ocean basin, to disappear beneath continents and island arcs.
sediment nezpevniná usazená hornina Loose, solid particles that can originate by (1) weathering and erosion of preexisting rocks, (2) chemical precipitation from solution, usually in water, and (3) secretion by organisms.
sedimentary environment sedimentaení prostoedí Area with specific conditions for deposition which are approximatelly the same on every place within the area.
sedimentary rocks zepvniné usazené horniny Rock that has formed from (1) lithification of any type of sediment, (2) precipitation from solution
sedimentation sedimentace See deposition.
seismic waves seismické vlny A wave of energy produced by an earthquake.
seismogram seismogram Paper record of earth vibration.
seismograph seismograf A seismometer with a recording device that produces a permanent record of earth motion.
sericite sericit Very fine-grained variety of muscovite. Mineral grains are usually not visible. The presence of sericite in a rock can be easily identified by typical silk luster. It is mineral typical for metamorphic rocks. Properties see micas.
serpentine serpentin Mineral typical for metamorphic rocks. Very dark green to black in colour, hardness varies from 3 to 5. Luster is dull to greasy, slight greasy feel. It forms very fine-grained (macroscopically massive) accumulations.
serpentinite serpentinit Type of metamorphic rock composed mostly of mineral serpentine. It is usually dark green to green-black in colour, massive and macroscopically dense. Joints of this rock are usually filled with chrysotile (asbestos).
shale boidlice A fine-grained sedimentary rock (grains finer than 0.06 mm in diameter) formed by the cementation of silt and clay (mud). Shale has thin layers (laminations) and an ability to split (fissility) into small chips.
shear force
The component of gravitational force that is parallel to an inclined surface.
shear strength smyková pevnost The resistance to movement or deformation of material.
shear stress smykové napití Stress due to forces that tend to cause movement or strain parallel to the direction of the forces.
sheet joints
Cracks that develop parallel to the outer surface of a large mass of expanding rock, as pressure is released during unloading.
shelf šelf Zone of sea bottom along all continents with varying width and dip 0.1%. It is bordered from one side by continental slope and from other side by continent.
shock metamorphism šoková metamorfóza The fastest type of metamorphism affecting surrounding rocks usually in tenths of second.
shrinking smrš?ování Decreasing of mineral and rock volumes caused by lowering of moisture.
schist krystalická boidlice A metamorphic rock characterized by coarse-grained minerals oriented approximatelly parallel.
silica oxid koemieitý A term used for oxygen plus silicon.
silicate silikáty A substance that contains silica as part of its chemical formula.
sill lo?ní ?íla A tabular intrusive structure concordant with the country rock.
sillimanite silimanit Mineral typical for metamorphic rocks. White, pale green or brown in colour, hardness varies from 6 to 7. It forms long, slender crystals, commonly as groups of parallel crystals.
silt prach Sediment composed of particles with a diameter of 0.002 mm to 0.06 mm.
siltstone prachovec A sedimentary rock consisting mostly of silt grains.
Silurian silur Geological period of Paleozoic between 408 ad 438 mil. of years ago.
sinkhole závrt A closed depresion found on land surfaces underlain by limestone.
sinter sintr A deposit of silica that forms around some hot springs and geysers.
slate boidlice A fine-grained rock that splits easily along flat, parallel planes.
slide sesuv In mass wasting, movement of a descending mass along a plane approximatelly parallel to the slope of the surface (see landslide).
slip sesuv In mass wasting, movement of a descending mass along one or more well-defined surfaces (see landslide).
slope angle úhel sklonu svahu Dip angle of a slope.
slump sesuv In mass wasting, movement along a curved surface in which the upper part moves vertically downward while the lower part moves outward (see landslide).
snow line sni?ná eára An irregular line making the highest level to which the winter snow cover on a glacier is lost during a melt season.
soil (1) puda, (2) zemina (1) A layer of weathered, unconsolidated material on the top of bedrock; often also defined as containing organic matter and being capable of supporting plant growth. (2) Geotechnical term for sediments, caving residual and volcanoclastic rocks.
soil moisture vlhkost zeminy Term expressing amount of water in soil by ratio between weight of water in a soil sample and weight of dry soil sample.
solifluction soliflukce Flow of water-saturated debris over impermeable material.
sorting toídiní Process of selection and separation of sediment grains according to their grain size (or grain shape or specific gravity).
specific gravity specifická hmotnost The ratio of the mass of an equal volume of water, determined at a specified temperature.
spring pramen A place where water flows naturally out of rock onto the land surface.
stalactite stalaktit Iciclelike pendant of dripstone formed on cave ceilings.
stalagmite stalagmit Cone-shaped mass of dripstone formed on cave floors, generally directly below a stalactite.
state of crystallization stupen krystalizace
staurolite staurolit Typical mineral of metamorphic rocks famous for its twinned crystals that form into the shape of a cross (or into the shape of the letter "X"). Shape of a crystals is columnar. Color is reddish-brown, brown, or black. Hardness is 7-7.5. Luster is vitreous to resinous to dull. Cleavage poor, in one direction. Fracture is uneven to conchoidal.
stock peo A small discordant pluton with an outcropping area of less than 100 square kilometers.
strain deformace Change in size (volume) or shape of a body (or rock unit) in response to stress.
streak vryp Color of pulverized substance; a useful property for mineral identification.
stream gradient
Downhill slope of a stream's bed or the water surface, if the stream is very large.
stream piracy
The natural diversion of the headwaters of one stream into the channel of another.
stream terraces oíení terasy Steplike landformes found above a stream and their flood plains.
stress tlak A force acting on a body, or rock unit, that tends to change the size or shape of that body, or rock unit. Force per unit area within a body.
striations podélné rýhování (1) On minerals, extremly straight, parallel lines; (2) Glacial-straight scratches in rock caused by abrasion by a moving glacier.
strike smir plochy The compass direction of a line formed by the intersection of an inclined plane (such as a bedding plane) with a horizontal plane.
strike-slip fault horizontální posun A fault in which movement is parallel to the strike of the fault surface.
structural geology strukturní geologie The branch of geology concerned with the internal structure of bedrock and the shapes, arrangement, and interrelationships of rock units.
structure textura Macroscopically distinguishable arrangement of mineral grains in a rock.
subduction zone subdukení zóna Mostly macroscopically distinguishable arrangement of mineral grains in a rock.
submarine canyon podmooský kaoon V-shaped valley that run across the continental shelf and down the continental slope.
superposition superpozice A principle or law stating that within a sequence of undisturbed sedimentary rocks, the oldest layers are on the bottom, the youngest on the top.
surface waves povrchové vlny A seismic waves that travel on the earth's surface.
swelling bobtnání Increasing of mineral and rock volumes caused bz raising of moisture.
syenite syenit A plutonic igneous rock consisting principally of alkali feldspar, usually with one or more mafic minerals such as hornblende or biotite. A small amount of plagioclase may be present. Also of quartz if less than 5%. Quartz-free granite. Name from Syene (Aswan), where it was later renamed "Aswan red granite".
syncline synklinála A fold in which the layered rock usually dips toward an axis.
tabular shape tabulkovitý tvar Table-like shape of minerals in a rock (e.g. feldspars). Two of three crystallographic axes are elongated, one is short.A fold in which the layered rock usually dips toward an axis.
talc mastek The softest mineral formed by metamorphic processes. It is the first member of Moh's scale.
tectonic forces tektonické síly Forces generated from within the earth that result in uplift, movement, or deformation of part of the earth's crust.
tension fault tahový zlom Fault in the earth's crust created by tensional forces.
tensional stress tahové napití A force that tends to elongate or pull apart a body.
terminus eelo ledovce The lower edge of a glacier.
terrigenous sediment suchozemský sediment Land-derived sediment that has found its way to the sea floor.
Tertiary toetihory Older period of Cenozoic (from 1.6 to 66.4 mil. of years ago).
texture struktura Macroscopically and microscopically distinguishable characteristics (size of particles, shape of particles, state of crystallization) of a rock.
thrust fault nasunutí A reverse fault in which the dip of the fault plane is at a low angle to horizontal.
till till Unsorted and unlayered rock debris carried by a glacier.
tillite tilit Lithified till.
tourmaline turmalín Black, pink, blue, green or brown mineral with vitreous luster. Hardness is from 7 to 7.5. It forms slender crystals with triangular cross-sections and striated sides.
trachyte trachyt Felsic volcanic rock composed mostly of K-feldspars, acidic plagioclases, biotite and hornblende.
transform boundary transformní rozhraní Boundary between two plates that are sliding past each other.
translucent prusvitný Term for a substance which transmits light, but if you place this substance over an image on paper you will not see it.
transparent pruhledný Term for a substance which transmits light and if place this substance over an image on paper you will see it.
transportation poenos (transport) The movement of eroded particles by agents such as rivers, waves, glaciers, or wind.
travertine travertin A porous deposit of calcite that often precipitates around springs that contain high amount of CaCO3.
Triassic trias The oldest period in Mesozoic (from 208 to 245 mil. of years ago).
tsunami tsunami Huge ocean wave produced by diplacement of the sea floor; also called seismic sea wave.
tuff tuf A rock formed from fine-grained pyroclastic particles (ash and dust).
turbidity current turbiditní proud A flowing mass of sediment-laden water that is heavier than clear water and therefore flows downslope along the bottom of the sea or a lake.
U-shaped valley údolí tvaru U Characteristic cross-profile of a valley carved by glacial erosion.
ultrabasic rocks ultrabazické horniny Type of igneous rocks with small amount of silica (<44%) composed mostly of basic plagioclases, pyroxenes and amhiboles.
ultramafic rocks ultramafické horniny Rocks composed entirely or almost of ferromagnesian minerals (Colour index >90).
unconfined aquifer volná zvodeo A partially filled aquifer exposed to the land surface and marked by a rising and falling water table.
unsaturated zone nenasycená zóna A subsurface zone in which rock openings are filled partly with air and partly with water; above the saturated zone.
upper mantle svrchní pláš? One of the inner shells of the earth.
valley glacier
A glacier confined to a valley. The ice flows from a higher to a lower elevation.
varve varva Two thin layers of sediment, one dark and other light in color, representing one year's deposition in a lake.
ventifact hranec Boulder, cobble, or pebble with flat surfaces caused by the abrasion of wind-blown sand.
viscosity viskozita Resistance to flow.
vitreous luster skelný lesk See glassy luster.
volcanic ash vulkanický popel Fine grained material (<2 mm) composed of rock fragments formed by volcanic explosion.
volcanic neck
An intrusive structure that apparently represents magma that solidified within the throat of a volcano. It forms isolated hill in surrounding denudated landscape.
volcanism vulkanismus Volcanic activity, including the eruption of lava and rock fragments and gas explosions.
volcano sopka A hill or mountain constructed by the extrusion of lava or rock fragments from a vent.
volcanoclastic rocks vulkanoklastické horniny Rock formed by lithification of rock fragments erupted from a volcano. Mineral composition is very similar to igneous rocks, structures and textures are similar to clastic sedimentary rocks.
water table hladina podzemní vody The upper surface of the zone of saturation.
weak zone oslabená zóna Zone in rock massif where rock properties are significantly worse then in surrounding rock.
weathering zvitrávání The group of processes that change rock at near the earth's surface.
well studna, sonda, vrt A hole, generally cylindrical and usually walled or lined with pipe, that is dug or drilled into the ground to penetrate an aquifer below the zone of saturation.
wind ripples
Small, low ridges of sand produced by the saltation of windblown sand.
xenolith xenolit Fragment of rock distinct from the igneous rock in which it is enclosed.
zone of accumulation zóna akumulace That portion of a glacier with a perennial snow cover.
zone of aeration provzdušnilá zóna See unsaturated zone.
zone of leaching zóna vyluhování Top layer of soil characterized by downward movement of water which leaches some mineral components.
zone of plastic flow zóna plastického teeení Lower zone of a glacier where plasticity limit of ice is exceeded.
zone of wastage zóna tání That portion of a glacier in which ice is lost or wasted.