Petrology (Done) Flashcards
(293 cards)
1
Q
These are naturally occurring solid substances which are aggregates of minerals
A
Rocks
2
Q
The ___________ and _________ affect the texture which reflects how the rock was formed.
A
Configuration and composition
3
Q
This refers to the web of processes that outline the major rock classifications form and breakdown on the different application of heat and pressure.
A
Rock Cycle
4
Q
The type(s) of energy required for rock cycle to occur.
A
Solar Energy (mainly for sedimentary rocks)
Earth’s Internal Engine (igneous and metamorphic rocks)
5
Q
It is concerned with rocks that are made up of definite mineral assemblages.
A
Petrology
6
Q
It is a descriptive study on the rock n its textural, mineralogical, and chemical parts.
A
Petrography
7
Q
It is the study on the general characteristics of rocks and employs knowledge from field exposures or hard specimens.
A
Lithography
8
Q
It deals with the origin of rocks.
A
Petrogenesis
9
Q
It is the study on the flow of mantle
A
Rheology
10
Q
It is a molten rock lighter than the surrounding rocks and works upward to reach the surface.
A
Magma
11
Q
Most magma are concentrated within ______ while they are less found along ______.
A
divergent zones and convergent zones
12
Q
It is the liquid component of the magma which is made up of mobile ions of the abundant elements.
A
Melt
13
Q
It is the crystallized silicate minerals from the melt
A
Solid Component of the Magma
14
Q
These are mainly water vapor, carbon dioxide, and sulfur dioxide which are vaporized at the surface pressures since these gases were confined at extreme subsurface pressures.
A
Volatiles
15
Q
A molten rock where all of its volatiles escaped and have reached the surface.
A
Lava
16
Q
_________ breaks down the ions which were arranged in a fixed manner. The atoms vibrate due to heat resulting to ions occupying spaces and expanding.
A
Increase in temperature
17
Q
The faster the vibration, the ions break away from their rigid configuration allowing ______ to occur.
A
Melting
18
Q
This allows the ions to migrate to join existing crystalline structures thus creating larger crystals.
A
Slow Cooling
19
Q
This is the increase of temperature with depth in the Earth
A
Geothermal Gradient
20
Q
Geothermal Gradient is about:
A
25 degrees per kilometer at the first 3-5kms
21
Q
It refers to the increase in temperature allowing melting to happen. It is governed by geothermal gradient which triggers melting.
A
Heat Transfer Melting
22
Q
Fluctuations in subsurface pressures decreases the rock’s melting point as the material is carried to an environment different from what was suitable to its former configuration.
A
Decompression Melting
23
Q
Increase in confining pressure causes increase in rock’s melting temperature making the material ________
A
Compact or less voluminous
24
Q
Decompression melting occurs in:
A
Zones of upwelling and hotspots
25
Water content affects melting which causes rocks to melt at lower temperatures thus it determines whether the rock exists either solid or liquid.
Flux Melting
26
Deeply buried "wet" rock has much _____ melting temperature than the dry rock of the same composition. Since the addition of water makes rock more buoyant allowing it to rise and disrupt its chemical bonding.
Lower
27
This happens when the earlier-formed minerals are denser than the liquid portion of the melt and thus sink down to the magma chamber.
Crystal Settling
28
This happens when one or secondary magma is formed from a single magma.
Magmatic Differentiation
29
The compositions change through the contamination of foreign material such as those of the surrounding rock.
Assimilation
30
This happens in the ascent of 2 chemically distinct magma bodies as the more buoyant mass overtakes the more slowly mass.
Magma Mixing
31
It is the incomplete melting of rock where it produces the most magma. These contain a melt of rocks with various melting temperatures along with a melt made of low temperature minerals
Partial Melting
32
Most magmas generated by partial melting are closer to _________ in composition.
Felsic
33
This describes the temperature at which minerals crystallize when cooled, or melt when heated. The low end of the temperature scale where all minerals crystallize into solid rock is approximately 700°C.
Bowen's Reaction Series
34
These are mafic/ iron-bearing that react discontinuously to form a next mineral in the series by decreasing temperatures.
Discontinuous Series
35
It represents the enrichment of Calcium to Sodium then to Potassium in Plagioclase Felspars with decreasing temperatures.
Continuous Series
36
This is a method of predicting the relative stability or weathering rate of igneous minerals once they are subjected to environments different from their formation.
Goldich Dissolution Series
37
Composition, Temperature, and the Number of Dissolved Gases
Factors in measuring volcanic activity
38
Magma associated with explosive eruption is ______ more viscous than a flowing magma.
5 times
39
The flow of magma is slowed when silicate structures start _____________
Polymerization
40
_____________ means more gas bubbles making magma more viscous and explosive.
Increase in water and gas content
41
The dissolved water in magma ____________ fluidity and ____________ polymerization.
Increases and decreases
42
Felsic magma explodes ________ due to the loss of the confining pressure to hold gases until the magma chamber is emptied.
in a series of eruptions
43
These eruptions contain gases of about 70% water vapor, 15% carbon dioxide, 5% nitrogen, and 5% sulfur dioxide with trace amounts of chlorine, hydrogen, and argon.
Hawaiian-Type Eruptions
44
These are flows of jagged blocks with sharp edges and spiny projections
Aa flows
45
these ae smooth, fluid surfaces like those of twisted ropes and end to form in much higher temperatures.
Pahoehoe Flows
46
These are hardened basaltic flows which contains cave-like tunnels that were once conduits.
Lava Tubes
47
These are felsic-intermediate magmas that generate short prominent flows which consists of vesicle-free detached blocks.
Block Lavas
48
These are pillow-shaped structures attributed to the extrusion of lava underwater or in subaqueous extrusion.
Pillow Lavas
49
These are low-viscosity basaltic magmas that produces fire fountains. These are generally non-explosive and produce very little pyroclastic emission.
Hawaiian Type Eruption
50
Distinct blasts of basaltic to andesitic magmas which produces incandescent bombs building smaller cinder cones. These are mildly explosive and produce a low elevation eruption columns and pyroclastic fall deposits.
Strombolian Eruption
51
These are sustained explosions of solidified or highly viscous andesite-rhyolite magma from the vent. These make widespread pyroclastic falls and are very explosive.
Vulcanian Explosion
52
A collapse of an andesitic or rhyolitic lava dome with or without a directed blast which produces Nuee Ardentes and known for being explosive.
Pelean Explosion
53
A sustained injection of andesitic-rhyolitic magma 45km from the vent and exhibits eruption collapse to produce pyroclastic flows and surges. Its ash cloud can circle the Earth thus they are violently explosive.
Plinian Explosion
54
This happens when a magma encounters a shallow groundwater and flashing it to steam. However, no new magma reaches the surface.
Phreatic Eruption
55
This happens when magma comes into contact with a shallow groundwater using a flash of steam which is ejected along with pre-existing fragments of the rock and tephra from magma. It less explosive than a Plinian eruption.
Phreatomagmatic Eruption
56
This happens when magma comes into contact with a shallow groundwater using a flash of steam which is ejected along with pre-existing fragments of the rock and tephra from magma. It less explosive than a Plinian eruption.
Phreatomagmatic Eruption
57
Effusive (Hawaiian)
0 Rank < 104 m3 (E.g. Kilauea-current)
58
Gentle (Hawaiian / Strombolian)
1 Rank > 104 m3 (E.g. Mt. Mayon -2006)
59
Explosive (Strombolian / Vulcanian)
2 Rank > 106 m3 (E.g. White Island-2019)
60
Severe (Strombolian / Vulcanian / Peléan / Sub-Plinian)
3 Rank > 107 m3 (E.g. Mt. Mayon -2001)
61
Catastrophic (Peléan / Plinian / Sub-Plinian)
4 Rank > 0.1 km3 (E.g. Taal- 2020)
62
Cataclysmic (Peléan / Plinian)
5 Rank > 1 km3 (E.g. Mt. St. Helens -1980)
63
Colossal (Plinian / Ultra-Plinian)
6 Rank > 10 km3 (E.g. Mt. Pinatubo- 1991)
64
Super-Colossal (Ultra-Plinian)
7 Rank > 100 km3 (E.g. Tambora- 1815)
65
Mega-Colossal (Ultra-Plinian)
8 Rank > 1,000 km3 (E.g. Yellowstone -640K years ago)
66
This refers to a pyroclastic material with a diameter greater than 64mm and angular fragments.
Blocks
67
These are pyroclastic materials with size 2-64mm size.
Lapilli
68
These are pyroclastic materials greater than 64mm size.
Lava Bombs/ Volcanic Bombs
69
It is the world's largest caldera with a size of 150km diameter. It is made up of 9 mile thick layer of volcanic rocks from 47.9-26 Million years ago.
Apolaki Caldera in the Benham Rise
70
Flux Melting is much more common in _____________ due to subduction.
Convergent Boundaries
71
These are constructed in between oceanic or between continental plates which give rise to volcanic islands.
Volcanic Island Arcs
72
These are constructed between oceanic to continental plates with the same mechanism with the volcanic arcs only that its is introduced to areas rich with silica.
Continental Volcanic Arcs
73
This forms volcanoes due to partial melting and decompression melting which then produces basaltic magma rising in the surface. It contributes to about 60% of magma output.
Divergent Boundaries
74
These occur in hotspots generated by mantle plume. These ascend to the surface forming flood basalts forming volcanic islands.
Intraplate Volcanism
75
Siberian and Deccan Traps were probably created by a mantle plume having a very ________ head and a very ______ tail.
Large, Long
76
These are structures formed from the emplacement of magma.
Plutons
77
These are produced when magma is forcibly injected into zones of weaknesses (i.e. fractures)
Tabular Intrusive Bodies
78
These are plutons formed from cutting across the structure.
Discordant
79
These are discordant sheet-like bodies that serve as conduits that transport magma and manifest as weathering resistant walls once exposed at the surface.
Dikes
80
These are roughly parallel groups branching from a single dike.
Dike Swarms
81
These are plutons that are placed parallel to structures.
Concordant
82
These are concordant sheet-like bodies that store magma. Once cooled and exposed to the surface, these manifest by columnar jointing.
Sills
83
These are large intrusive bodies with 100 sq.km in size composed of felsic-intermediate rocks.
(Granite) Batholiths
84
These are igneous intrusions with size lesser than that of a batholith
Stocks
85
A viscous sill with a dome-shaped structure forcibly injected between sedimentary strata giving a mushroom like appearance.
Laccolith
86
These are produced by the accumulation of fluid basaltic lavas with a prominent dome structure. These start off as seamounts eventually forming volcanic islands
Shield Volcanoes
87
Steep sided structures built from ejected lava fragments that take on the appearance of clinkers as they begin to harden in flight.
Cinder Cones/ Scoria Cones
88
These are manifestations of plate tectonics especially along subduction zones. It is formed from gas-rich magma having an andesitic composition and are known to generate an explosive eruption ejecting huge quantities of pyroclastic material.
Stratovolcano/ Composite Volcanoes
89
A hollow within a volcano where magma and gases settle.
Magma Chamber
90
A pipe-like passageway where magma and gases escape.
Conduit
91
_____________ work by expanding the fractures along the sides of the wall then eroding it forming conduits.
High Pressure Gases
92
The opening on the surface of a volcano that emits lava, gases, ash, or other Volcanic material
Vent
93
These are formed when explosive eruptions occur.
Crater
94
These are cone-shaped accumulations of volcanic material not part of the central vent.
Parasitic Cones
95
These are parasitic cones that only eject gases.
Fumaroles
96
Circular depressions greater than 1km that emits lava, gases, ash or other volcanic materials. These are produced after an explosive eruption which only lasts for a few hours to few days.
Caldera
97
This is formed where a collapse of the summit from a silica-rich pumice and ash.
Crater-lake Type
98
The collapse of the top of a shield volcano. This is due to subsidence as magma is drained laterally from the underlying magma chamber.
Hawaiian Type
99
The collapse of a large area caused by a discharge of colossal volumes of silica rich pumice and ash along ring fractures.
Yellowstone Type
100
These are spots where lava emerges in the ground rather in the form of a volcanic cone or a vent
Fissures
101
A giant volcanic eruption resulting to large stretches of land or ocean floor filled with basaltic lava.
Flood Basalts
102
A mound shaped protrusion resulting to slow extrusion of viscous lava from volcanoes.
Lava Dome
103
Felsic lava given that they hardly flow at all produces lava domes of ____________ in height, forming in flanks or summits of composite volcanoes.
10m - 1km
104
A channel bored through the crust allowing molten magma chamber to travel up and out during volcanic eruption.
Volcanic Pipe
105
These are formed from the congelation of magma or consolidation of volcanic breccia in the conduit and may be exposed by weathering
Volcanic Necks/ Volcanic Plugs
106
This is where magmas migrate upward and travel rapidly enough that they go little alteration during ascent. These run up to 200kms in depth.
Diatremes
107
These are turbulent, fast-moving cloud of hot gas and ash erupted as columns of material collapse.
Nuee Ardentes
108
These are powerful hot blasts that carry small amounts of ash that separate from the body of flow.
Surges
109
The crystallization of magma is dependent on the following factors:
(1) Rate of Cooling
(2) Silica Content
(3) Amount of Dissolved Gases Present
110
These are formed at subsurface conditions. Coarse-grained containing visible crystals.
Intrusive Igneous Rocks/ Plutonic Igneous Rocks
111
These are formed when molten rocks are solidified at the surface. These are fine-grained and may form from any volcanic debris.
Extrusive Igneous Rocks/ Volcanic Igneous Rocks
112
Igneous Rocks are classified based on __________ and _________
Texture and Composition
113
It is formed at the surface or in small intrusive masses within the crust where it is a product of rapid cooling. It exhibits light to dark color and are equally fine-grained.
Aphanitic Texture
114
These are mainly extrusive rocks that contain voids left by gases. These are formed from the upper zone of the lava flow.
Vesicular Texture
115
This is formed when large masses of magma cool at a great depth, creating a mass of intergrown crystals roughly equal in size and are large. These are equally coarse-grained.
Phaneritic Texture
116
This forms when magma crystallizes below the volcano allowing crystallization to occur but due to changing conditions, some minerals are cooled before completing crystallization.
Porphyritic Texture
117
This refers to the large crystals in rocks with porphyritic texture.
Phenocrysts
118
The mineral background of porphyritic rocks
Groundmass
119
These are formed from rapid cooling of magma where crystallization cannot occur resulting into little to no crystals.
Glassy Texture
120
Formation of a rock of glassy texture is contributed by:
Rapid Cooling and Polymerization
121
It refers to any process in which small molecules combine chemically to produce a large chain-like structure or network molecule. This is seen among obsidian flows.
Polymerization
122
The consolidation of individual rock fragments ejected during volcanism.
Pyroclastic (Fragmental) Texture
123
This happens when cooling produces huge crystals in consequence of a fluid-rich environment that enhances crystallization rather than slow cooling, It occurs in small masses or thin veins around intrusive bodies.
Pegmatitic Texture
124
The chemical makeup of an igneous rock can be inferred by its ____________
Silica Content
125
These rocks contain >63% Silica. It contains minerals alkali-feldspar, acid plagioclase, and quartz attributing to its light color. These are the major constituents of the continental crust.
Acidic Igneous Rocks/ Felsic Rocks/ Granitic Rocks
126
Felsic Magmas are viscous due to its high silica content. Volcanoes of this type erupts at ______ degrees.
700
127
This contains 52-63% silica and 25% dark silicates. It has a mineral makeup of granite and basalt with amphibole and intermediate feldspars. These are common across margins of continents
Andesitic Rocks/ Neutral Igneous Rocks/ Intermediate Igneous Rocks
128
It has low silica at 45-62% with high concentration of Magnesium and Iron making it darker in color and slightly denser. These make up the majority the world's ocean floor.
Basaltic Rocks/ Basic Igneous Rocks/ Mafic Rocks
129
Mafic magma erupts at temperatures ranging from ________ to ______ degrees.
1,100 - 1250
130
Mafic magmas turn to solid when temperatures are about ______.
1000
131
It is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz at 40-60%, alkali feldspar at 50-80%, and plagioclase at 10%. It contains small amounts of ferromagnesians such as hornblende, biotite, and augite)
SG = 2.2-2.7
Granite
132
It is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock
Quartz Monzonite
133
It is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing twice the number of plagioclase feldspar than orthoclase feldspar with lesser amounts of quartz.
Granodiorite
134
It is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali feldspar making up less than 10% of the total feldspar content.
Tonalite
135
The extrusive equivalent of Granite; mainly quartz, potassium feldspar, and biotite. These are fined-grained an indication of rapid cooling. Phenocrysts of this rocks are mainly alkali feldspar to quartz.
SG = 2.4 - 2.6
Rhyolite
136
It is formed from rhyolitic magma but manifests as a porous volcanic glass without phenocrysts due to rapid cooling.
Obsidian
137
A very porous volcanic glass with full of unrelated glass bubbles. It is known to float in water.
Pumice
138
Extrusive equivalent of Granodiorite
Dacite
139
Extrusive equivalent of Quartz Monzonite
Dellenite
140
It is an igneous intrusive rock that has a moderate silica content and is enriched in alkali metal oxides. This is composed mostly of equal amounts of plagioclase and alkali feldspar. This capable in hosting gold and silver deposits.
Monzonite
141
It is an intrusive igneous rock that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silica (mafic) gabbro and high-silica (felsic) granite. These are found along areas of orogeny along with its extrusive equivalent.
SG = 2.8 - 3
Diorite
142
It is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a granitoid having 20-40% hornblende.
Syenite
143
A porphyritic rock which is the extrusive equivalent of Diorite
Andesite
144
Extrusive equivalent of Monozite
Latite
145
Extrusive Equivalent of Syenite
Trachyte
146
Extrusive Equivalent of Nepheline Syenite
Phonolite
147
It is mainly composed of ferromagnesians and calcium rich plagioclase containing less Olivine with dark gray color. It is common in the oceanic crust
Gabbro
148
It is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro which occurs as sills, dikes, plugs of volcanic basalt or volcanic gabbro. It is composed of 60% mafic plagioclase in a matrix of 20-30% augite clinopyroxene and 10% Olivine
Dolerite/ Diabase
149
It is a mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite, orthopyroxene, and olivine. Indistinguishable from Gabbro since it is in close association with mafic gabbro complexes.
Norite
150
It contains 90-100% plagioclase feldspar with 10% pyroxene capable of hosting titanium, aluminum, and precious gems.
Anorthosite
151
It is the extrusive equivalent of Gabbro-Norite containing calcium rich plagioclase, ferromagnesians, and 20% quartz. It has dark-green to black aphanites but when porphyritic it has olivine phenocrysts.
SG = 2.8 - 3
Basalt
152
The ejecta from basaltic magma. It contains reddish-brown fragments the size of lapilli
Scoria
153
These are produced from submarine volcanism composed of clinopyroxenes and plagioclase.
Tholeiitic Basalts
154
It contains phenocrysts of olivine, titanium rich only that it is poor in silica and high in sodium.
Alkali Basalt
155
Sodium-rich volcanic rock formed by turning basalt by albitization process at low temperatures in the presence of carbon dioxide. This is a metasomatic rock due to the hydrothermal alteration of basalt. These are mostly seen in pillow lavas.
Spilite
156
It is composed of >45% ferromagnesians with >45% silica for an ultramafic rock. This is the main constituent of the mantle.
Peridotite
157
It is a coarse-grained rock consisting of 40 to 90% olivine along with significant orthopyroxene and lesser amounts of calcic chromium-rich clinopyroxene. Minor minerals include chromium and aluminum spinels and garnets.
Lherzolite
158
It is a variety of peridotite consisting mostly of the two minerals olivine and low-calcium (Ca) pyroxene (enstatite).
Harzburgite
159
A rock composed mainly of pyroxenes where it occurs at the base of the intrusive chamber or thin layers within peridotites.
Pyroxenites
160
A veins igneous rock composed of quartz and potassium feldspar which are found in granites and granodiorites.
Aplites
161
These are veins rock with a dark-gray color containing ferromagnesians with little light colored minerals. This is found in intrusive-extrusive Syenite.
Lamprophyre
162
These are cemented tiny ash fragments
Tuff
163
These are streamlined fragments solidified in air with particles larger than ash.
Volcanic Breccia
164
It is formed when ash remained hot enough to fuse with glass shards, pumice, and obsidian.
Welded Tuff
165
It is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). It characteristically fills with water to form a relatively shallow crater lake.
Maar
166
These are rocks containing light colored minerals due to low content of ferromagnesians.
Leucocratic Rocks
167
These are rocks that contain 60-100% ferromagnesians thus having a dark color.
Melanochromatic Rocks
168
These are rocks which are classified according to their Quartz, Feldspar, and Biotite
Major Group
169
Rocks having mineral constituents which are classified by the special name designated to the said rock. (i.e. Olivine Gabbro- olivine serves as a modifier due to gabbro containing a lot of olivine)
Important Group
170
It contains minerals that are unimportant and not relevant rock. (i.e. Granite containing zircon- due to zircon not relevant to granite formation)
Rock with Minor Minerals
171
A rock which contains minerals that do not occur during the formation and was later introduced during secondary processes. (i.e. Kaolinite from the weathering of feldspar rocks or Serpentinite due to hydrothermal modification of Olivine)
Rock with Secondary Minerals
172
It is the degree of similarity in particle size of rocks with either they may be well or poorly organized.
Sorting
173
Wind deposits are ________ than wave deposits
Well sorted
174
Rocks washed by waves are ________ than deposited in streams
Better sorted
175
The rounder the rock particle, the ______ it must have travelled and the ______ the particle is.
longer, older
176
It is the collective term for all chemical, mechanical, and biological changes after sediments are deposited and during, after lithification.
Diagenesis
177
Temperature regimes during diagenesis are about:
150°C - 200°C
178
The process which unconsolodated sedimentas are transformed into solid Sedimentary Rocks.
Lithification
179
This occurs when sediments are deeply buried placing them under pressure due to weight of overlying layers where fluids are forced out.
Compaction
180
It refers to the hardening and welding of clastic sediments by precipitation of mineral matter in pore spaces.
Cementation
181
These are sedimentary rocks that formed layer upon layer of sediment accumulating in various depositional environments
Strata/ Bed
182
A flat surface along which rocks tend to separate or break.
Bedding Planes
183
It forms on a sloping surface such as ripple marks and dunes
Cross-bedding
184
These are small waves of sand developed in the surface of a sedimentary layer by the action of moving water and air currents
Ripple Marks
185
These are formed due to changes in weather patterns. It manifests as cracks when the land has dried out
Mudcracks
186
The steeper sides in the current direction and more gradual slope on the up-current side.
Current Ripple Marks
187
The remains of prehistoric life encased or engraved on sedimentary rocks
Fossils
188
These sedimentary rocks display discrete fragments that are cemented and compacted together which all detrital rocks are included
Clastic Sedimentary Rocks
189
These are composed of crystals that may resemble igneous rocks but differ in composition
Non-clastic Sedimentary Rocks
190
These are formed from the accumulation of sediments derived from mechanical or chemical weathering
Detrital Sedimentary Rocks
191
These are rocks mainly formed from chemical processes such as alteration or precipitation
Chemical Sedimentary Rocks
192
These are formed from the precipitation of material as a result of inorganic processes by organisms
Organic Sedimentary Rocks/ Biochemical Sedimentary Rocks
193
These are unbound angular clastic sediments of greater than 2mm diameter accumulated by sudden and rapid rockfalls.
Debris
194
Unbound accumulation of rock minerals, sand, dust, and clay that are well-rounded clasts of greater than 2mm.
Gravel
195
A rock consisting of well-rounded clasts
Conglomerate
196
A rock which occurs in the form of angular fragments
Breccia
197
The accumulation of unbound moraine ranging from >2mm in size
Till
198
These are poorly sorted rocks made of blocks of rocks and clay matrix and forms by lithification from glacial processes
Diamictite
199
These are rocks referred to as pure sandstones
Arenites/ Arenaceous Rocks
200
These are rocks containing less than 75% Quartz and Feldspar of 25% which has more fragments than rock.
Arkose
201
These are impure sandstones of dark color and are poorly sorted. An angular rock usually found in submarine deposits by turbidity currents.
Greywacke
202
These are rocks that contain clay minerals such as illite, smectite, and kaolinite
Clay/ Claystone
203
A rock made of montmorillonite clay group formed from the alteration of acidic tuffs and volcanic glass.
Bentonite
204
A pelite which consists of more than 66% silt grain size rocks containing grains of feldspar and mica flakes with up go 33% clay
Siltstone
205
A thinly laminated fine-grained pelite made up of siliciclastic materials.
Shale
206
It is a known property of shale which it splits into thin layers along well-developed, closely spaced planes.
Fissility
207
These are homogeneous, solid lithified rock containing a mixture of particle clays and powder.
Mudstone
208
A periglacial or aeolian sediment with <20% clay and has equal parts of sand and silt
Loess
209
A mixed carbonate-clay rock and composed of cryptocrystalline or microcrystalline calcite and siliciclastic detritus of pelites.
Marlstone
210
A volcaniclastic rock composed of pieces of lava containing 75% bombs embedded in a matrix of volcanic ash and tuff
Agglomerate
211
These are glassy tuffs in which lithification is manily a result of crystallization in pneumatolytic activities
Sillar Tuffs
212
This is a mixture of 25-75% volcanic or volcaniclastic rock and 75-25% rocks of sedimentary origin
Tuffite
213
This represents the 10% volume of all sedimentary rocks thus the most abundant. It is made up of calcium carbonate either sourced by biochemical or inorganic means
Limestone
214
A friable limestone formed from the accumulation of calcareous shell fragments of foraminifera
Chalk
215
A poorly cemented limestone composed of sand-sized fragments of calcareous shell and/or coral debris
Coquina
216
This is where the calcite in the rock begins to transform when subjected to heat, pressure, and chemical activity.
Crystalline Limestone
217
This is composed of calcite but some are altered to form dolomite
Dolomitic Limestone
218
A limestone which contains obvious and abundant fossil remains.
Fossiliferous Limestone
219
A dense rock with very fine and very uniform grain size known to be used in lithography (the earliest form of printing)
Lithographic Limestone
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These form small clasts of spherical rounded calcite formed by the concentric accumulation of calcite layers
Oolitic Limestone
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These are formed in geothermally heated alkaline water and subsurface caverns precipitating to help form speleothems
Travertine
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A porous rock formed from the precipitation of calcium carbonate in a hot spring or other heated surface water.
Tufa
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A rock that contains the mineral dolomite and has the same appearance with limestone
Dolomite/ Dolostone
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Main difference between limestone and dolomite is that dolomite ________ when poured with acids unlike Limestone
Never reacts
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It is said that a limestone comes into contact with magnesium rich waters which converts calcium ions to magnesium ions.
Dolomitization
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These are water-soluble rocks resulted from the concentration and crystallization by evaporation from an aqueous solution
Evaporites
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This refers to the group of rock with silica as its main component
Siliceous Rocks
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A rock which is very hard, dense, low porosity composed of diatoms cemented with opal or in older rocks.
Diatomite
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Rocks with thick glassy shine composed of radiolaria skeletons and fibrous chalcedony aggregates
Radiolarite
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These are rocks composed of spicule silica sponge
Spicularite
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This rock is formed from the secretion of opal from hot surface waters.
Geyserite
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A rock porous and softer than chert with a blurry shine of white color.
Porcelanite
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A white-light gray porous silicon sediment that occurs by partial silicification of carbonate rocks.
Tripoli
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A hard fine-grained rock composed of microcrystalline to cryptocrystalline quartz. It has conchoidal fracture and dominated by quartz.
Chert
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A process that leads to changes in the mineral content, texture, and sometimes the chemical composition of rocks
Metamorphism
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This refers to the conditions of temperature and/or pressure to which a rock has been subjected to measuring the degree of metamorphism
Grade
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This happens when the differences between the protolith and the resultant metamorphic rock are subtle.
Low-grade Metamorphic Rock
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This happens when the features of the protolith are almost removed.
High-grade Metamorphism
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These are the agents of metamorphism:
Heat, Confining Pressure and Differential Stresses, Chemically Active Fluids, and the Parent Rock (Protolith)
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An agent in metamorphism that provides energy to drive chemical reaction resulting to recrystallization and formation of new minerals. This turns minerals to become chemically unstable until a point these become stable.
Heat
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The substantial chemical changes accompanying metamorphism
Metasomatism
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This causes the spaces between mineral grains to close and also allows recrystallization in increasing depth.
Confining Pressure
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These squeeze the rock in a particular direction enough to cause folding
Differential stresses by tectonic processes
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Hot fluids enhance metamorphism by ____________ and _______ ions from one site in the crystal structure to another.
Dissolving and transporting
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Intrusion causes metamorphism but with only a little scope due to __________ such as Quartz
Unreactive minerals
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Once intrusion occurs along sites with reactive minerals such as limestone, metamorphism _________.
Exceeds beyond intrusion
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The arrangement of mineral grains or structural texture within a rock, a characteristic of regionally metamorphosed rock.
Foliation
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Foliation is caused by ___________ exerted on a rock which causes the mineral grains to develop parallel alignments.
Compressive Stresses
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A foliated metamorphic texture, aphanite-like appearance which can be split into thin slabs
Rocky Cleavage/ Slaty Cleavage
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Foliated texture formed in high temperatures where mica and chlorite crystals grow which exhibits a planar/ layered structure.
Schistocity
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A hard compact high grade metamorphic texture resulting to ion migration of minerals and does not split into pieces.
Gneissic Texture
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A texture where platy or tabular minerals are aligned top produce a planar fabric. This is due to the parallel orientation during the recrystallization of minerals having a flaky or scaly habit.
Lepidoblastic Texture
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Prismatic minerals are oriented to produce a linear fabric.
Nematoblastic Texture
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These typically develop in environments where deformation is minimal and the parent rocks are made of minerals that exhibit equidimensional crystals.
Non-foliated Texture
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The large crystal encased in a fine-grained matrix where crystallization happens between diverse metamorphic minerals.
Porphyroblastic Texture
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A non-foliated texture which contains visible grains forming triple junction of 120 degrees as seen in hornfels
Granoblastic Texture
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Porphyroblast with small or fine-grained inclusion of the precious rock in it.
Poikiloblastic Texture
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Non-foliated texture where crystals are formed without a developed crystallographic faces.
Xenoblastic Texture
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The magma is injected to a solid rock baking it thus altering its composition. Rocks formed in this environments are mostly non-foliated.
Contact Metamorphism
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It is related to mountain-building processes especially in subduction zones having a geothermal gradient.
Regional Metamorphism/ Barrovian Metamorphism
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It shows the degree of metamorphism from contact area to unmetamorphosed country rock in some distance away.
Contact Aureoles
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A change in mineral assemblages with increases temperature and pressure conditions resulting to high density larger crystals. It is associated with increasing grade.
Prograde Metamorphism
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A change in mineral assemblages notably with decreasing grade due to uplift (decompression) and cooling.
Retrograde Metamorphism
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A high-pressure metamorphism resulting from the crushing and shearing of rock during tectonic movement, mostly along faults. This is generally localized along fault planes producing mylonites.
Cataclastic Metamorphism/ Fault-zone Metamorphism
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This occur where massive amounts of sedimentary or volcanic material accumulates in a subsiding basin creating low-grade metamorphism due to diagenesis, confining pressure, and geothermal heat.
Burial Metamorphism
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With mechanisms similar to burial metamorphism only that it is concentrated in subduction zones where a rock is subjected to extreme differential stresses.
Subduction Zone Metamorphism
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Rocks are formed from impact events creating impactiles which are a manifestation of high-energy impact on earth.
Impact Metamorphism
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The chemical alteration of rocks involving hydrothermal fluids producing rock units having economic values.
Hydrothermal Metamorphism
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It is made along intense grinding and crushing force along tectonic zones generating elongated grains giving foliation.
Mylonites
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Mylonite and phyllite hybrid composed of crushed quartz-feldspar
Phyllonite
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A strong crushing of coarse crystalline gneiss having large lenticular eye shaped minerals in a mylonite matrix.
Augen Gneiss
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A clay-rich rock usually shale or mudstone that came into contact with an intrusive body.
Hornfels
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Calcareous rocks that came into contact with an intrusive body.
Skarn
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A medium-coarse grained metamorphic rock which is a lot of platy minerals. It is formed under major mountain building events.
Schist
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A schist composed of biotite and muscovite having a high degree of progressive metamorphism.
Mica Schist
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A schist composed of basic magmatic rocks with minerals such as hornblende and feldspars.
Amphibole Schist
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A metamorphism of a rock containing sillimanite, cordierite, and staurolite.
Disten
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The medium coarse grained banded metamorphic rock containing quartz, where granular and elongated minerals predominate.
Gneiss
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Most gneisses have ________ composition derived from granite or rhyolite.
Felsic
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An amphibole rich rock with gneissic texture that occurs along mica schists and gneisses.
Amphibolite
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An amphibolite with pelitic sediments, clay, and limestone as its protolith.
Para-amphibolites
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An amphibolite with neutral to basic igneous rocks of amphibole, hornblende, and albite.
Ortho-amphibolites
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A hard metamorphic rock often formed from quartz sandstone of high temperature and high pressure regimes.
Quartzite
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A coarse crystalline rock whose protolith was limestone or dolostone. It is formed from combined effect of high temperature and high-pressure.
Marble
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A fine-grained metamorphic rock composed of minute mica flakes. It is a low-metamorphosed shale and other pelites.
Slate
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A gradation between slate to schist which contains minerals muscovite or chlorite. It has a glossy green color and exhibits rock cleavage.
Phyllite
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A silvery gray fine sheet Phyllite transitioning to mica schist. It contains sericite and quartz.
Sericite Schist
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A greenish fine to medium grained schist resulting from basic igneous rocks of low temperature.
Chlorite Schist
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A regional low-grade metamorphism of basalt, diabase, feldspar arenite, greywacke and marl
Glaucophane Schist
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The transformation of ultrabasic rocks and serpentinite that occurs by hydrothermal metamorphism from olivine.
Talc Schist
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A very-high pressure and high-temperature rock having different mineral composition of quartz and feldspar along with pyroxene and garnets.
Granulites
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It is formed in extremely high temperature and high pressure environments from basic migmatites with a little presence of peridotites.
Eclogite
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A deformed micro-folded, mixed igneous and metamorphic rocks by the partial melting of gneiss.
Migmatites.
