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?