LE2 Flashcards
(279 cards)
1
Q
Activities or phenomena that occur on the Earth’s surface.
A
Exogenic Processes
1
Q
The _______ is an ever-changing sphere shaped by forces operating both within and upon its surface.
A
Earth
2
Q
It is the detachment of earth material from the surface of the earth.
A
Erosion
3
Q
It is a dynamic process and includes the transportation of disintegrated rock materials away from their origin.
A
Erosion
4
Q
Changes the shape of coastlines.
A
Erosion by Water
5
Q
Waves constantly crash against shores.
A
Erosion by Water
6
Q
They pound rocks into pebbles and reduce pebbles to sand.
A
Erosion by Water
7
Q
Water sometimes takes sand away from beaches. This moves the coastline farther inland.
A
Erosion by Water
8
Q
It carries dust, sand, and volcanic ashes from one place to another.
A
Erosion by Wind
9
Q
_________ can sometimes blow sand into towering dunes.
A
Wind
10
Q
__________ can erode the land.
A
Erosion by Ice
11
Q
In frigid areas and on some mountaintops, glaciers move slowly downhill and across the land. As they move, they pick up everything in their path, from tiny grains of sand to huge boulders.
A
Erosion by Ice
12
Q
It is defined as loosening and breaking of rock masses by the pressure of glacial ice.
A
Glacial Plucking
13
Q
Glacial Plucking is also called ________.
A
Glacial Quarrying.
14
Q
It is the rubbing, scratching, grooving and polishing action of the glaciers on the rock surface along or over which these ice masses happen to move.
A
Glacial Abrasion
15
Q
_________ pulls any loose bits down the side of a hill or mountain.
A
Gravity
16
Q
When rocks break down over time because of things like rain, wind, and even plants growing in cracks.
A
Weathering
17
Q
It’s like nature’s way of slowly wearing away at rocks, turning them into smaller pieces.
A
Weathering
18
Q
Refers to the process of breaking down rocks into smaller fragments without changing their chemical composition.
A
Physical Weathering
19
Q
It occurs through physical forces and processes that cause rocks to fracture or disintegrate into smaller pieces.
A
Physical Weathering
20
Q
It occurs in cold climates where temperatures frequently fluctuate above and below freezing.
A
Ice Wedging
21
Q
It occurs when rocks are porous or permeable.
A
Freeze-thaw weathering
22
Q
It is also known as exfoliation, occurs when overlying material is removed from a rock’s surface.
A
Release of Pressure
23
Q
It is the roots grow into cracks and push rocks apart.
A
Growth of Plants
24
It burrow and push apart rocks.
Animals
25
It is the process by which rocks and minerals are broken down and altered through chemical reactions with water, gases, and other substances in the environment.
Chemical Weathering
26
It is the process where sediment, soil, or rock particles that have been transported by erosional agents such as water, wind, ice, or gravity are deposited or laid down in a new location.
Deposition / Sedimentation
27
It is the opposite of erosion, where materials are removed from one area.
Deposition / Sedimentation
28
It can freeze sediment and then deposit it elsewhere as the ice carves its way through the landscape or melts.
Glaciers
29
Sediment created and deposited by glaciers is called ________.
Moraine
30
__________ are made of rocky sediment worn down by wind and collision with other sand particles.
Sand Dunes
31
It is a type of mass wasting that results in the sliding of coherent rock materials along a curved surface.
Slump
32
It is the slow downhill flow of soil.
Solifluction
33
Release of Pressure is also known as _________.
Exfoliation
34
_________ dissolves rock chemically
Water
35
It is the process of oxidation. Rocks with iron mixes with oxygen, rusts.
Oxygen
36
It is the acids from plants and roots chemically weather rocks.
Living Organisms
37
It can move dirt across a plain in dust storms or sandstorms.
Wind
38
It is the movement of rock and soil downward due to gravity.
Mass Wasting
39
A downward viscous flow of fine-grained materials that have been saturated by water and moves under the pull of gravity
Earthflow
40
It is a mud travels down a slope very quickly.
Mudflow
41
It is a type of slide characterized by the chaotic movement of rocks, soil, and debris mixed with water or ice.
Debris Slide
42
It is a moving mass of loose mud, sand, soil, rock, water, and air that travels down a slope under the influence of gravity.
Debris Flow
43
It occurs when pieces of rocks break loose from a steep rock face or cliff.
Rock Flow
44
A slow, gradual movement of soil downhill over time.
Soil Creep
45
It is an internal geomorphic process.
Endogenic Processes
46
This energy is mostly generated by radioactivity, rotational and tidal friction and primordial heat from the origin of the earth.
Endogenic Processes
47
This energy due to geothermal gradients and heat flow from within induces diastrophism and volcanism in the lithosphere.
Endogenic Processes
48
It is when two forces push towards each other from opposite sides, the rock layers will bend into folds.
Folding
49
It is fracturing and displacement of more brittle rocks strata along a fault plan. The process of forming a fault.
Faulting
50
The beak in a rock along which a vertical or horizontal rock movement has occurred.
Fault
51
The line of fault is referred as the _________.
Fault Line
52
It is a volcanic activity or igneous activity. Eruption of molten rock (magma) onto the surface of the Earth.
Volcanism
53
It occurs when there is pressure and heat applied to geologic structures which leads to the formation of metamorphic rocks
Metamorphism
54
It is a seismic activity. A sudden shaking or vibration on the Earth’s crust.
Earthquake
55
_________ are powerful and dynamic geological agents. The water flowing through a stream performs three kinds of geologic works as erosion, transportation and deposition.
Rivers
56
The longest river in the world with a span of *6,650 km. *
Nile River
57
The longest river in the Philippines with a span of *505 km. *
Cagayan River
58
The second longest river with a span of *6,400 km. *
Amazon
59
He is the Scottish Geologist and mathematician, proposed that a river carve its own valley.
John Playfair
60
This law indicates how deep valleys and landforms have been formed.
Playfair's Law
61
The rivers transport sediment, ranging from fine silt to large boulders, from one place to another.
Transportation
62
This movement of material helps shape the river's course and the surrounding landscape.
Transportation
63
Rivers erode the land they flow over, gradually wearing away rock and soil to create valleys and other landforms.
Erosion
64
The force of the water, combined with the sediment it carries, acts like sandpaper, grinding down the riverbed and banks.
Erosion
65
When the river loses energy, it deposits the sediment it has been carrying.
Deposition
66
This process can create various landforms, such as deltas, floodplains, and alluvial fans, contributing to the ongoing transformation of the landscape.
Deposition
67
The movement of air over the surface of the earth is called _________.
Wind
68
Wind deposits are also called _________.
Aeolian Deposits
69
It is the act of removing the loose particles of the earth from one area and forming depression.
Deflation
70
By this process of removing the sand to the groundwater level, _________ is formed in the desserts.
Oasis
71
It is the process of impact of the coarse particles in the wind against formations like understanding rock and eroding them.
Abrasion
72
This reduction of velocity forces deposition of the particles the wind is carrying, and they form typical Aeolian deposits.
Deposition
73
It is a heap of sand conical in cross section with a gentle slope on the windward side and a steeper slope on the leeward side.
Sand Dunes
74
Understand wind-driven processes and their effects in erosion, deposition, and transportation because they may impose significant challenges to infrastructure stability and land use suitability.
Site Evaluation
75
Wind-blown sand and dust can accumulate around structures, affecting foundation stability and structural integrity. Engineers must consider wind-induced soil movement and sedimentation when designing foundations, retaining walls, and other geotechnical structures in windy environments.
Foundation Design
76
It is generally used for saline water bodies surrounded by landforms and also water bodies of shallower depth less than 4 km.
Sea
77
It is the waves created by the winds.
Sea Waves
78
________ are waves which only goes up and down.
Oscillatory Waves
79
The word _________ means pertaining to the shoreline.
Littoral
80
The movement of water up to the coast when the waves break is called _________.
Swash
81
The return of water back into the sea is called _________.
Backwash
82
The word littoral means pertaining to the shoreline.
Littoral Currents
83
The cracks in the cliff are filled with waves and its sudden release during the retreat of waves causes the material around the cracks to break up.
Hydraulic Action
84
These are massive structures built along the coast.
Seawalls
85
These are made of steel, concrete, or timber piles and they are used where the impact of waves are not very large.
Bulkheads
86
Understanding coastal processes and dynamics is crucial for coastal engineering projects, including shoreline protection, beach nourishment, and coastal infrastructure design.
Coastal Engineering
87
Marine geologists and engineers study seabed geology, sediment transport, and oceanography to assess resource potential, plan extraction operations, and minimize environmental impacts.
Marine Resources Management
88
This deals with study of minerals.
Mineralogy
89
It deals with the detailed mode of formation, composition, occurrence, types, association properties, etc.
Mineralogy
90
It is a naturally-occurring, homogeneous, solid with a definite but generally not fixed, chemical composition and an ordered atomic arrangement.
Mineral/s
91
It is usually formed by inorganic processes.
Mineralogy
92
The ________ represents the common node of occurrence of a mineral in nature.
Form
93
It is also called Habit or Structure of minerals.
Form and Habits
94
To come extent this is the function of the atomic structure of minerals.
Form and Habits
95
Minerals appear as Thin Separable Layer
- Mica
Lamellar Form
96
Minerals appears slab of uniform Thickness.
- Feldspar
Tabular Form
97
Minerals appear to be made of small spherical grain.
- Bauxite
Pisolitic Form
98
Minerals appear to be made of still small spherical grain.
- Limestone
Oolitic Form
99
Minerals appear to be made of innumerable equidimensional grain of coarse or medium of grain.
- Magnetite, Chromite
Granular Form
100
Minerals appear as a cluster or independent lath shaped grains.
- Kyanite
Bladed Form
101
Minerals appears as made up of smaller curved faces like bunch of grapes
- Hematite, Chalcedony
Botryoidal Form
102
Minerals appear as made up of thin needles.
- Natrolite, Actinolite
Acicular Form
103
Minerals appears as long slender prism.
Columnar Form
104
Minerals appear as elongated independent crystals.
- Quartz, Apatite
Prismastic Form
105
Minerals appear as porous.
- Pyrolusite, pumice
Spongy Form
106
Minerals appear as Polyhedral Geometric Shapes.
- Amethyst, Pyrite, Galena
Crystal Form
107
No definite shape of minerals.
- Graphite, olivine, jasper
Massive Form
108
Irregular shaped compacted bofy with curved surface.
- Flint
Nodular Form
109
It is due to composition.
Color
110
Are minerals that process inherent color due to their chemical composition.
Idiochromatic Minerals
111
Copper (Cu) is the chromophore, giving malachite its characteristic green color.
Malachite (Green)
112
Copper (Cu) is again chromophore, but in a different chemical environment within the azurite structure, leading to a blue color.
Azurite (Blue)
113
Mercury (Hg) is the chromophore, imparting vivid red color to cinnabar.
Cinnaber (Red)
114
These are minerals that display a variety of colors due to the presence of impurities or imperfections within their crystal structure, rather than their inherent chemical composition.
Allochromatic Minerals
115
Minerals rich in AI, Ca, Na, Mg are often __________.
Light Colored
116
Minerals rich in Fe, Ti, Ni, Cr are often ________.
Dark Colored
117
It reflects all components of white light.
White Minerals
118
It absorbs all components of white light.
Black Minerals
119
It reflects green light and absorb the others.
Green Minerals
120
It is defined as the color of a mineral’s powder obtained by rubbing a mineral specimen on an unglazed white porcelain tile.
Streak
121
It is defined as the way in which mineral reflects light and it is controlled by atomic structure of the minerals.
Luster
122
It is the nature of shining on the surface of minerals
Luster
123
Based on quality or type of shining, ________ are grouped as metallic and non-metallic.
Luster
124
It is useful in identifying metallic ore materials.
Streak
125
It is a type of shining appears on the surface of metals.
Metallic Luster
126
The amount of shining is less compared to metallic luster.
Sub-Metallic Luster
127
The non-metallic minerals shining like a silk.
Silky Luster
128
The non-metallic minerals shining like a Resin.
Resinous Luster
129
The non-metallic shining like a diamond.
Adamantine Luster
130
The non-metallic minerals shining like Earth or Chalk.
Earthy or Dull Luster
131
It is defined as the tendency of minerals to beak along a flat surface or to break unevenly along a cured surface of irregular surface.
Fracture
132
It is a mineral property where the atomic bonding between atoms in crystal structure is perfect with no weakness.
Fracture
133
When these materials are stressed they shatter making no two pieces truly the same.
Fracture
134
It is the uneven breakage of minerals.
Fracture
135
Define as the broken surface of the minerals is plain and smooth.
Even Fracture
136
It is defined as the broken surface of the minerals is rough or irregular.
Uneven Fracture
137
It is defined as the broken surface of minerals are very irregular like broken stick.
Hackly Fracture
138
It is define as the broken surface of the minerals is smooth and curved surface.
Conchoidal Fracture
139
It is defied as the resistance offered by minerals to abrasion or scratching.
Hardness
140
It is also related to atomic structure of minerals.
Hardness
141
The _________ of mineral appear to have a less influence over hardness.
Chemical Composition
142
The _________ of unknown minerals is determined by scratching it with the minerals of Mohs scale of hardness, starting with the talc and followed by minerals.
Relative Hardness
143
It is a qualitative ordinal scale that characterizes the scratch resistance of different minerals through the ability of hardness material to scratch a softer material.
Mohs Scale of Hardness
144
The German geologist and mineralogist who created Mohs Scale of Hardness in year 1812 and is one of several material science definitions of hardness.
Friedrich Mohs
145
It is the ratio of the mass of substance to the mass of a reference substance for the same given volume.
Specific Gravity (Density)
146
_________ of minerals depends on their chemical composition and aotmic structure.
Specific Gravity (Density)
147
_________ of minerals is determined by using either Walker’s steel yard or Jolly’s spring.
Specific Gravity (Density)
148
4.5 – 6.0
Sulfides
149
8.0
Iron Metal
150
13.0
Lead
151
19.0 – 22.0
Gold and Platinum
152
The resistant offered by materials to the passage of light through them.
Degree of Transparency
153
_________ depends on chemical composition.
Degree of Transparency
154
It mainly depends on thickness.
Degree of Transparency
155
Light is able to pass through _________ minerals.
Transparent
156
_________ minerals partially let light pass through.
Translucent
157
_________ minerals do not let any light through.
Opaque
158
It is very soft. (h = 1)
Talc
159
It exhibits smooth touch or soapy feel.
Talc
160
It is low hardness. (h = 1)
Graphite
161
It exhibits black color. Marks easily on paper.
Graphite
162
It gives garlic smell. When struck or heated and freshly broken surface.
Realgar
163
It gives a clayey smell and adheres strongly to tongue.
Kaolin
164
It has saline taste.
Halite
165
petro = _________
logy = _________
Rock
Study
166
It is the scientific study of rocks that deals with their composition, texture, and structure; their occurrence and distribution; and their origin in relation to physicochemical conditions and geologic processes.
Petrology
167
It concerned with all three major types of rocks – igneous, metamorphic, and sedimentary.
Petrology
168
It is the most important branch of geology from civil engineering point of view.
Petrology
169
It involves the laboratory synthesis of rocks for the purpose of ascertaining the physical and chemical conditions under which rock formation occurs.
Petrogeny
170
It deals with the mode of formation of rocks.
Petrogeny
171
It is the study of rocks in thin section by means of petrographic microscope (i.e., an instrument that employs polarized light that vibrates in a single plane0.
Petrography
172
It is primarily concerned with the systematic classification and precise description of rocks.
Petrography
173
It deals with descriptive part of rocks.
Petrography
174
_________ relies heavily on the principles and methods of mineralogy because most rocks consist of minerals and are formed under the same conditions.
Petrology
175
These are the primary rocks, which are formed due to cooling and solidification of magma.
Igneous Rocks
176
It is from the latin word _________, meaning “fire”.
Ignis
177
It is a hot vicious, siliceous melt, containing water vapor and gases.
Magma
178
When magma comes out from the greater depth below the earth surface, such as magma is called _________.
Lava
179
Are formed from magma that cools and solidifies within the crust of a planet, surrounded by pre-existing rock.
Intrusive Igneous Rocks
180
The magma cools slowly and, as a result, these rocks are coarse-grained.
Intrusive Igneous Rocks
181
The mineral grains in such rocks can generally be identifies with the naked eye.
Intrusive Igneous Rocks
182
These are formed at intermediate depth generally up to 2 km below the earth surface and exhibits mixed characteristics of volcanics and plutonic.
Hypabyssal Rocks
183
These are formed at considerable depth generally up to 7-10 km below the earth surface.
Plutonic Rocks
184
Because of very slow rate of cooling at these depth coarse grained rocks are formed.
Plutonic Rocks
185
It is also called as volcanic rocks.
Extrusive Igneous Rocks
186
These rocks are formed due to cooling and solidification of magma at the crust surface.
Extrusive Igneous Rocks
187
The magma, which is brought to the surface through fissured or volcanic eruptions, solidifies at a faster rate. Hence, such rocks are smooth, crystalline and fine-grained.
Extrusive Igneous Rocks
188
These are formed due to cooling and solidification of lava erupted from volcanoes. Since lava cools down at very fast rate, the grain size of the crystal formed in these rocks is fine.
Volcanic Rocks
189
_________ are those, which are formed by the accumulation, compaction and consolidation of sediments.
Sedimentary Rocks
190
The sediments are the particles produces from disintegration of pre-existing rocks (igneous/metamorphic rocks)through the process of transportation and deposition by various natural agents like wind, water and glaciers.
Sedimentary Rocks
191
It is when eroded sediments end up in the water begin to settle.
Sedimentation
192
With time, more layers pile up and presses down the lower layers
Compaction
193
It is when salt crystal glue the layers together
Cementation
194
They are
mechanically formed rocks.
Clastic Deposit Rocks
195
These are
formed due to the process of
weathering, erosion, transportation and
deposition of pre-existing rocks.
Clastic Deposit Rocks
196
If the grain size are more than 2mm in diameter.
Rudaceous Rocks
197
If the grain size is in between 1 and 2mm.
Arenaceous Rocks
198
If the size of the particle is < 1mm in diameter.
Argillaceous Rocks
199
Clastic Deposit Rocks (Rudaceous Rocks) example
Conglomerate and Breccia
200
Clastic Deposit Rocks (Arenaceous Rocks) example
Quart Sandstone and Grit
201
Clastic Deposit Rocks (Argillaceous Rocks) example
Shale and Mudstone
202
They are formed by precipitation, evaporation or crystallization from natural aqueous solution.
When water is rich in dissolved salt
evaporates and left behind minerals
(Halite).
Chemical Deposit Rock
203
_________ can form when calcite
minerals dissolved in lakes, sea and
underground water comes out of
solution and form crystal.
Limestone
204
They are formed exclusively from remains of organisms like plant/animals deposited in a thick layer.
Organic Deposit Rock
205
These are rocks that are formed as a result of transformation that takes place in pre-existing rocks (igneous/sedimentary
rocks).
Metamorphic Rocks
206
When the pre-existing rocks are subjected to higher temperature,
pressure and chemically active liquids and gases, the minerals present in the
original rocks changes to new environmental condition.
Metamorphic Rocks
207
Meta = _________
Morph = _________
Change
Form
208
_________ means to change form.
Metamorphism
209
When the pressure squeezes the flat or elongate minerals within a rock so they become aligned.
Foliated
210
These rocks develop a platy or sheet-like structure that reflects the direction that pressure was applied in.
– Slate and
Schist
Foliated
211
The metamorphic rocks are formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions. – Marble
Non-Foliated
212
It is usually said to begin with a hot molten liquid rock called magma or lava
The Rock Cycle
213
It is rocked’ physical and chemical breakdown into smaller fragments, and erosion removes those fragments from their original location.
Weathering
214
It is a water that has infiltrated
the ground to fill the spaces between
sediments and cracks in rock.
Groundwater
215
It is recharged by precipitation,
snowmelt, or water seepage from other
sources, including irrigation and leaks
from water supply systems.
Groundwater
216
Existing _________ can be discharged
through springs, lakes, rivers, streams, or
manmade wells.
Groundwater
217
These are formed where the water table naturally meets the land surface, causing groundwater to flow from the surface and eventually into a stream, river, or lake.
Springs
218
To ensure a continuous supply of water, a _________ must penetrate below the water table; too much pumping of _________ can cause drawdown (lowering of the water table permanently)
Well
219
It is a stagnant water body and does not empty into any other water body.
Lake
220
It is a flowing water body that ends up in a sea or an ocean, connects to a larger water body; a natural flow of running water that follows a well-defined, permanent path, usually within a valley.
Rivers
221
It is also called a brook
or a creek.
Spring
222
It is a natural flow of water that follows a more temporary path that is usually not in a valley
Spring
223
It is an underground boundary between the soil surface and the area where groundwater saturates spaces between sediments and cracks in rock.
Water Table
224
The soil surface above the water table is called the _________, where both oxygen and water fill the spaces between sediments.
Unsaturated Zone
225
The unsaturated zone is also called the zone of _________.
Aeration
226
Water found in this zone of aeration is called _________, and is distinct from groundwater.
Soil Moisture
227
Underneath the water table is the __________, where water fills all spaces between sediments.
Saturated Zone
228
The __________ is bounded at the bottom by impenetrable rock.
Saturated Zone
229
The water derived from precipitation (rain and snow) although bulk of the rainwater or melt water from snow and ice reaches the sea through the surface flows or runoffs a considerable part of precipitation gradually infiltrates into ground water.
Almost entire water obtained from ground water supplies belongs to this category
Meteoric Water
230
This infiltrated water continuous its downward journey till it reaches the zone of saturation to become the ground water in the aquifer.
Meteoric Water
231
Groundwater is contained and flows
through bodies of rock and sediment
called _________.
Aquifer
232
Fluctuations in the water table level are caused by _________ between seasons and years.
Changes in Precipitation
233
Incomplete
compaction may cause retention of
some water by these rocks which is
known as the _________.
Connote Water
234
The water that is present in the rocks right from the time of their deposition aqueous environment
Connote Water
235
It is also called magmatic water and is of only theoretical importance as far as water supply scheme is concerned.
Juvenile Water
236
It is the water found in the cracks or crevices or pores of rocks due to condensation of steam emanating from hot molten masses or magmas existing below the surface.
Juvenile Water
237
Some hot springs and geysers are clearly derived from juvenile water.
Juvenile Water
238
Occurs when the rate of groundwater extraction through wells is higher than the rate of replenishment from precipitation.
Groundwater Depletion
239
Ground sinks when water is pumped from wells faster than natural recharge processes can replace it
Subsidence
240
A common problem in coastal areas where excessive groundwater withdrawal causes saltwater to be drawn into wells, thus contaminating the freshwater supply.
Saltwater Contamination
241
All earth materials from soils to rocks
have pore spaces.
Saturated Formation
242
It is a saturated formation of earth material which not only stores water but yields it in sufficient quantity.
Aquifer
243
It is a formation through which only seepage is possible and thus the yield is insignificant compared to an aquifer.
Aquitard
244
It is a geological formation which is essentially impermeable to the flow of water.
Aquiclude
245
The amount of time that groundwater remains in aquifers is called its __________, which can vary widely, from a few days or weeks to 10 thousand years or more.
Residence Time
246
It is the one in which water table forms the upper surface of the zone of saturation.
Unconfined Aquifer
247
An aquifer where the water table is the upper surface limit and extends below till the impermeable rock strata is called the unconfined aquifer.
Unconfined Aquifer
248
An aquifer that is sandwiched between two impermeable layers, it is known as a _________.
Confined Aquifer
249
It is also known as a pressure aquifer, or an artesian aquifer.
Confined Aquifer
250
These are are completely filled with water, and they do not have a free water table and the aquifer will be under pressure
Confined Aquifer
251
Confined aquifer i also known as _________.
Pressure aquifer
or
Artesian aquifer
252
It is a special type of an unconfined aquifer.
Perched Aquifer
253
An impermeable saucershaped stratum of a small aerial extent occurring in the zone of aeration may retain and hold some amount of water is called _________.
Perched Aquifer
254
_________ is an example of aquiclude.
Clay
255
Like surface waters, is also a very powerful natural agent responsible not only for modifying the existing features but also for creating many other geological features on and below the surface of the earth.
Ground Water
256
A typical terrain, in which the surface and subsurface features in general and relief and drainage in particular are related directly to the solvent action of groundwater
The Karst Topography
257
A centripetal drainage in which streams from different directions flow towards common central basin.
The Karst Topography
258
Where the solution forms are exposed on the surface.
Bare Karst
259
Where the rocks bearing features of solvent action are present under a thin cover of insoluble rock.
Covered Karst
260
Where the cover over the affected rocks is quite thick.
Subjacent Karst
261
These are also termed as swallow holes, sink holes and sometimes simply as sinks.
Dolines
262
A typical _________ is a circular or oval depression, which when followed in depth becomes bowl-shaped or cylindrical in cross section.
Dolines
263
Measuring 660m deep, with a volume of 130 million cubic meters, China's _________ is both the deepest and largest sinkhole in the world.
Xiaoxhai Tiankeng
264
It was only "discovered" by the outside world in 1994, and experts still aren't sure how it formed.
Xiaoxhai Tiankeng
265
These may be defined as naturally carved out underground cavities of various dimensions that always have horizontal openings on the surface.
Caves
266
They are similar to tunnels with the exception that a _________ does not normally have an exit whereas a tunnel has an entry on one end and an exit on the other end.
Caves
267
These are formed due to pronounced and prolong solvent action of groundwater on the subsurface rocks.
Caves
268
The most famous cave of the world, the _________, is more than 250 km in aggregate
length.
Mammoth Cave in Kentucky, United
States
269
It consists of more than 200 chambers clustered together.
Mammoth Cave in Kentucky, United
States
270
These are typical topographic features of many karst regions.
Blind Valleys
271
A _________ is a valley like feature where a stream flowing through it in the upper reaches suddenly disappears in the lower reaches.
Blind Valleys
272
It is a system of 12 caves, covering an area of 2,968 hectare. This is probably the largest cave system in Southeast Asia, and most of it is still unexplored.
Calbiga Caves
273
These are the icicle like carbonate projections that hang down from the roof of the cave.
Stalactites
274
They may acquire fantastic shapes like slender rods and cones with flattened bases attached firmly with the roof, and may project for any length, even almost touching the floor of the cave.
Stalactites
275
These are also groundwater deposits of the same category as the stalactites but are made by deposition from the carbonate-rich droplets from ground upwards.
Stalagmites
276
The drops of water dripping from the cave lose carbon dioxide during downward fall in a regular manner.
Stalagmites
277
This deposit grows upward getting thicker also in the process.
Stalagmites
278
_________ is thus deposited at the floor of the cave just below the dripping water.
Calcium Carbonate
