Geology Test 2
Dikes and sills
High-angle and low-angle igneous intrusions
Ground mass grains
Porphyritic rocks are named for the size of:
Initial slow cooling and then fast cooling
Porphyritic textures indicate:
Geologic processes occurring now happened throughout earths history
Principle of uniformitarianism states that:
Gulf of Mexico
Sediments eroded from the Putnam County by the Candy Fork river may be deposited in:
Bowen's reaction series
Shows that minerals in a cooling magma crystallize in a predictable order
Volatile passages in an igneous rock
Vesicles in vesicular textures are remnants of:
A, B and D
A conglomerate sample consists of well-rounded clasts of granite, angular clasts of micaschist, and individual mineral fragments derived from granite and mica-schist. What can you infer about the source region of the sandstone? A. The basin where sandstone was deposited received sediments from both igneous and metamorphic terrains B. igneous terrain was closer to the source than the metamorphic terrain C. Metamorphic terrain was closer to the source than the igneous terrain D.the combined source region dominant mineralogy( considering both the terrains together) is quartz, feldspar, biotite, Muscovite
Granite
A course grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K-feldspar may be called:
All of them( igneous, metamorphic, and sedimentary rocks)
A dike intrudes into:
Wet magma
A magma that is rich in volatiles is called:
Individual crystals can be seen with the naked eye
A phaneritic texture is one in which:
Individual crystals are a mix of coarse and fine-grained crystals
A porphyritic texture is one in which:
Sample B traveled more distance than sample A
A sandstone sample A has subangular sand grains, while a sandstone sample B has rounded sand grains. Which of the following statements are true?
Mudcracks
A small stream in an arid region which is experiencing severe droughts for a few years continuously is expected to best preserve the following sedimentary structure:
Pores are abundant
A vesicular texture is one in which:
All of these( fine-grained, derived from lava, cooled faster)
All Aphanitic textures are:
Phaneritic texture
All intrusive igneous rocks have:
All of these( coarse-grained, derived from magma, cooled slowly)
All phaneritic textures are:
All of them( a change in River flow velocity, a change in slope of the land, deposition of sediments eroded from mountain tops)
Alluvial fan is a type of depositional environment where the following happens:
Rise and fall of sea level
Alternating red and black shales in a sedimentary sequence indicate that the deposition environment experienced...
Individual crystals cannot be seen with the naked eye
An Aphanitic is one in which:
Ultramafic rock
An igneous rock containing <45% SiO2 is called:
Pyroclastic texture
Another name for fragmental texture is:
Weathering-erosion-deposition-burial-compaction-cementation
Arrange in correct order the set of processes leading to a clastic rock formation
Average flow direction
Cross beds indicate:
Phenocrysts
Coarse-grained crystals in porphyritic textures are called:
Mafic to ultramafic
Composition of the earths mantle is:
Aphanitic or glassy or fragmental texture
Extrusive igneous rock textures can be:
Light color shades
Felsic igneous rocks tend to have:
LIPs
Flood basalts are characteristic of:
Both b and c( volcanic ash, and volcanic rock debris)
Fragmental texture is formed from:
Columbia River Flood Basalts
Give an example of a LIP in continental U.S.
Hawaii
Give an example of a location experiencing hotspot-induced volcanism?
East African Rift
Give an example of a place currently undergoing continental rift tectonic setting.
Magma
Hot rock melt inside the earth is called
Lava
Hot rock melt on the earths surface is called
No
In Q.29, would you expect olivine as a mineral fragment in the sandstone?
All of them( water vapor, carbon-dioxide, sulphur dioxide)
In a flux-induced melting, which of the following can act as flux?
Hotspots
Intra-plate volcanism is seen at:
Felsic magma
Is more viscous than mafic magma
Large igneous provinces
LIP is:
Continental rifting, sea floor spreading, mantle plume
List 3 tectonic and/or mantle processes that trigger decompression melting.
Subduction zones, mid ocean ridges, continental rifts, and hotspots
List 4 tectonic settings where igneous activity occurs:
Burial, compaction, cementation
Lithification involves:
Dark colored shades
Mafic igneous rocks tend to have:
Both a and c ( felsic melts and extrusive settings)
Pyroclastic flow occurs in:
Current flow conditions
Ripple marks on a sandstone indicate:
All of them( sedimentary, igneous, metamorphic rocks)
The Grand Canyon carved out by the Colorado River exposes:
Limestone
The dominant rock-type in coral reefs:
Labrador, Canada was a shallow marine underwater region close to the Equator
The early Cambrian(500 Ma) rocks in Labrador, Canada contain ancient coral reefs preserved in rocks. What can you infer about the paleo-geographic position of the Labrador region 500 million years ago?
I is older than both B and C
Three sedimentary rock layers A, B, and C are arranged in layers with A at the bottom and C at the top. An igneous dike I has intruded the rock layer A but it did not intrude B and C. Which of the following statements about I is true?
All of them(C is younger than B and A, A and B are older than I, C is younger than I)
Three sedimentary rocks layers A,B, and C are arranged in layers with A at the bottom and C at the top. An igneous dike I had intruded the rock layers A and B but it did not intrude C. Which of the following statements is true?
Chamber A
Two magma chambers of similar size are undergoing crystallization. Chamber A is tabular. Chamber B is spherical. Which chamber cools faster?
Chamber Y
Two magma chambers of similar size are undergoing crystallization. Chamber X is 10 km below the earths surface. Chamber Y is 50 km below the earths surface. Which chamber cools slower?
Reducing marine conditions
What does a black shale tell about its depositional environment?
The environment of deposition was exposed to atmosphere
What does red shale tell us about its depositional conditions?
Number of sources involved
What does sorting of a clastic sedimentary rock indicate?
Great Barrier Reef
What is the giant reef system along the coast of NE Australia known as?
Overburden Pressure
What is the primary factor that keeps the mantle rocks from melting at very high temperatures of 3000 degrees C?
Mafic fine-grained
What kind of igneous rocks do you expect at mid-ocean ridges?
Flex-induced melting
What kind of melting do you expect at subduction zones?
Decompression melting
What kind of melting do you expect in a continental rift tectonic setting?
Decompression melting
What kind of melting do you expect just under a mid-ocean ridge?
Breccia
What would you call a rock that has pebble-sized angular clasts?
Shale
What would you call a very-fine clastic grained sedimentary rock with clay minerals?
Beach
Where would you expect a chemical sedimentary rock like rock salt to be deposited?
Swamps
Where would you expect coal to be deposited?
Breccia-conglomerate-sandstone-shale
Which of the following arrangements represent a correct sequence of deposition away from the source?
Chalk
Which of the following is a biochemical sedimentary rock?
Oolithic limestone
Which of the following is a chemical sedimentary rock?
Calcite
Which of the following is a dominant mineral in limestone?
Quartz
Which of the following is a dominant mineral in sandstone?
Ultramafic<mafic<intermediate<felsic
Which of the following melt compositions are arranged in the order of increasing viscosity?
Ultramafic<mafic<intermediate<felsic
Which of the following melt compositions are arranged in the order of increasing volcanic explosivity?
Basalt melts
Which of the following melt compositions do you expect to travel long distances?
All of them( olivine, pyroxene, amphibole)
Which of the following minerals crystallize via the discontinuous reaction series?
Ca-rich plagioclase and Na-rich plagioclase
Which of the following pairs of minerals are part of the continuous reaction series in Bowen's Reaction series?
Coal
Which of the following rocks can be ignited?
Obsidian
Which of the following rocks display a stunningly black glassy texture?
Coquina
Which of the following rocks is made up entirely of shells of marine organisms
Tuff
Which of the following rocks is not derived from an igneous rock melt?
All of them( micrite, fossiliferous limestone, chalk)
Which of the following rocks would you expect to react with acid?
All of them( they are arranged in layers, they are mappable, they may contain sedimentary structures)
Which of the following statements are true about sedimentary formations?
All of them( Aphanitic, phenocrysts, ground mass)
Which of the following words may be used to describe portions of rock with porphyritic texture?
Molten rock is less dense than the surrounding solid rocks
Why does molten rock move upward through the earths mantle?