Geology Test 2

Which of the following is a biochemical sedimentary rock?

Chalk

Give an example of a LIP in continental US.

Columbia River Flood Basalts

What kind of melting do you expect at a subduction zones?

Flux-induced melting

With increasing P, inside the Earth:

High density minerals are formed

Dikes and sills are:

High-angle and low-angle igneous intrusions

What does sorting of clastic sedimentary rock indicate?

Number of sources involved

What is the primary factor that keeps the mantle rocks from melting very high temperatures of 3000 C?

Overburden pressure

Metamorphic grade implies

P, T conditions of a rock environment

Metamorphism implies:

P, T, Stress, Fluids conditions of a rock environment

Which of the following is a chemical sedimentary rock?

Oolitic Limestone

A vesicular texture is one in which:

Pores are abundant

burial metamorphism is common in:

Sedimentary basins

The Grand Canyon carved out by the Colorado River exposes:

Sedimentary rocks, Igneous rocks and Metamorphic rocks

What would you call a very-fine clastic grained sedimentary rock with clay minerals?

Shale

Bowens Reaction Series:

Show that minerals in a cooling magma crystallize in a predictable order.

Which is the correct sequence for increasing grain size inside the Earth?

Slate-Phyllite-Schist-Gneiss

Reheating

(heating a rock without melting it)

Which of the following is a possible metamorphic temperature?

450 C

In the above diagram in Q53, which of the following data sets represents an approximately accurate dataset that describes the pressure (kbar), temperature (C) and depth (km) of a rock at point B?

50, 1700, 150

Alluvial fan is a type of depositional environment where the following happens:

A change in river flow velocity, A change in slope of the land and Deposition of segments eroded from the mountain tops

Which of the following situations are impossible in nature?

A granite rock with olivine and A metamorphic rock with marine shell fragments

Extrusive igneous rock textures can be:

Aphanitic or glassy or fragmental texture

Which of the following words may be used to describe portions of rocks with porphyritic textures?

Aphanitic, Phenocrysts and Groundmass.

Cross beds indicate:

Average flow direction

Which of the following melt compositions do you expect to travel long distances?

Basalt Melts

Where would you expect a chemical sedimentary rock like rock salt to be deposited?

Beach

What would you call a rock that has a pebble-size angular clasts?

Breccia

Which of the following arrangements represent a correct sequence of deposition away from the source (i.e. closest to farthest)?

Breccia-Conglomerate-Sandstone-Shale

Lithification

Burial Compaction Cementation

Lithification involves:

Burial, Compaction and Cementation

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 layers A and B but it did not intrude C. Which of the following statements is true?

C is younger than B and A, A and B are older than I, C is younger than I

Which of the following pairs of minerals are part of the continuous reaction series in Bowen's Reaction Series?

Ca-rich plagioclase and Na-rich plagioclase

What is the dominant mineral composition of marble?

Calcite

Which of the following is a dominant mineral in limestone?

Calcite

Two magma chambers of similar size are undergoing crystallization. Chamber A is tabular. Chamber B is spherical> Which chamber cools faster?

Chamber A

Two magma chambers of similars size are undergoing crystallization. Chamber X is 10 km below the Earths surface. Chamber Y is 50km below the Earth's surface. Which chamber cools slower?

Chamber Y.

A low-grade metamorphic rock containing chlorite-biotite-muscovite is subjected to higher P/T conditions. Which of the following minerals will be replaced first during neo-crystallization?

Chlorite

Name an organic sedimentary rock.

Coal

Which of the following rocks can be ignited?

Coal

All phaneritic textures are:

Coarse-grained, derived from magma and cooled slowly

Which of the following processes can turn a sedimentary rock into a metamorphic rock?

Contact metamorphism, Subduction metamorphism and Burial metamorphism

List 3 tectonic and/or mantle processes that trigger decompression melting.

Continental rifting, sea floor spreading and mantle plume

Which of the following rocks is made up entirely of shells of marine organisms?

Coquina

Ripple marks on a sandstone indicate:

Current flow conditions

Mafic igneous rocks tend to have?

Dark-color shades

What kind of melting do you expect just under a mid-ocean ridge?

Decompressing melting

What kind of melting of you expect in a continental rift tectonic setting?

Decompression melting

Graphite in a metamorphic rock is stable up to a certain P/T condition. Imagine metamorphic rock containing graphite is subjected to more intense P/T conditions, such that graphite becomes unstable at the new P/T conditions. What will be the resulting new mineral phase?

Diamond

Give an example of a place currently undergoing continental rifting.

East African Rift

Quartzite and marble lack foliation because they have:

Equant mineral grains

Which of the following tectonic processes cools rocks inside the Earth?

Exhumation

Pyroclastic flow occurs in:

Felsic melt flows and Extrusive settings

All aphanitic textures are:

Fine grained, derived from lava and cooled faster

Principal of uniformitarianism states that:

Geologic processes occurring now happened throughout Earth's history

The characteristic mineral for subduction zone metamorphism which impacts a blue hue to the subduction zone metamorphic rocks is:

Glaucophane

Which of there following rocks contain banded foliations? (Check all that apply)

Gneiss and Migmatite

During metamorphism recrystallization, there is a change in:

Grain size of the protolith minerals and Texture

A coarse-grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K-Feldspar may be called:

Granite

What is the giant reef system along the coast of NE Australia known as?

Great Barrier Reef

Porphyritic rocks are named for the size of:

Groundmass grains

Sediments eroded from the Putnam County by the Casey Fork river may be deposited in:

Gulf of Mexico

Give an example of a location experiencing hotspots-induced volcanism?

Hawaii

The rock-type produced by contact metamorphism is called?

Hornfels

Intra-plate volcanism is seen at:

Hotspots

Chemical alteration of ocean floor basalts is an example of:

Hydrothermal Metamorphism

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 layers A but did not intrude B and C. Which of the following statements about I is true?

I is older than both B and C.

A dike intrudes into:

Igneous rock, sedimentary rock and metamorphic rock

A porphyritic texture is one in which:

Individual crystals are a mix of coarse and fine-grained crystals

A phaneritic texture is one which:

Individual crystals can be seen with the naked eye

An aphanitic texture is one in which:

Individual crystals cannot be seen with the naked eye

Porphyritic textures indicate:

Initial slow cooling and then fast cooling

A metamorphic rock-specimen contains the minerals muscovite and biotite but no chlorite. What can you infer about the P/T conditions where the rock formed?

Intermediate P/T

Feslic Magma:

Is more viscous than mafic magma

As a mantle rock moves from A to B in this diagram below, what happens? Moving from Solid line upwards towards crust.

It begins to melt via decompression.

In the above diagram in Q.53, Point A represents a rock that fits with which of the following descriptions?

It has a pressure of 100,000 bars.

Flood basalts are characteristic of:

LIPs

The early Cambrian (500 Ma) rocks in Labrador, Canada contain ancient coral reefs preserved in rocks. What can you infer about the paleo-geographic positions of the Labrador region 500 million years ago?

Labrador, Canada was a shallow marine underwater region close to the Equator

LIP is:

Large Igneous Provinces

Hot rock melt on the Earth's surface is called?

Lava

Felsic igneous rocks tend to have?

Light-color shades

The dominant rock-type in coral reefs are:

Limestone

What is the parent rock for marble?

Limestone

Hot rock melt inside the Earth is called?

Magma

Match the P/T conditions with the corresponding rock environment pair:

Low T/High P metamorphism - Accretionary Prism High T/Low P metamorphism - Volcano tops High P/High T metamorphism - Deeper parts of subduction zones Dynamic metamorphism - Mylonites

What kind of igneous rocks do you expect in a continental rift tectonic setting?

Mafic fine-grained

Composition of the earth's mantle is:

Mafic to ultramafic

How would you get an igneous rock from another igneous rock?

Melting

Which of the following rocks would you expect to react with acid?

Micrite, Fossiliferous limestone and Chalk

Which of the following is a mixed rock?

Migmatite

Which of the following rocks have banded foliations?

Migmatite

During metamorphism in a compressive stress field, how does the minerals acquire preferred orientation?

Minerals long axes align normal to the direction of maximum compressive stress

Why does molten rock move upward through the Earths mantle?

Molten rock is less dense than the surrounding solid rocks

Regional metamorphism is typical of:

Mountain belts

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:

Mudcracks

In Q29, would you expect olivine as a mineral fragment in the sandstone?

No

Which of the following rocks display a stunningly black glassy texture?

Obsidian

Which of the following minerals crystallize via the discontinuous reaction series?

Olivine, Pyroxene and Amphibole

All intrusive igneous rocks have:

Phaneritic texture

Coarse-grained crystals in porphyritic textures are called?

Phenocrysts

Another name for fragmental texture is?

Pyroclastic texture

Which of the following is a dominant mineral in sandstone?

Quartz

When a sandstone is metamorphosed, it turns to:

Quartzite

Which of the following metamorphic rocks are coarse-grained?

Quartzite, Gneiss and Schist

What does a black shale tell about its depositional environment?

Reducing marine conditions

How would you get a gneiss from phyllite?

Reheating

How would you get a metamorphic rock from an igneous rock?

Reheating

alternating red and black shales in a sedimentary sequence indicates that the deposition environment experienced?

Rise and fall of sea-level

In most types of metamorphism, bulk element composition of parent rock is:

Same as that of the parent rock

A sandstone sample A has sub angular sand grains, while sandstone sample B has rounded sand grains. Which of the following statements are true?

Sample B traveled more distance than sample A

Which of the following metamorphic rocks have visible mineral grains?

Schist

Which of the following rocks may be a photolithography of gneiss?

Schist, Shale and Granite

Which is the correct sequence for increasing metamorphic grade inside the Earth?

Slate-Phyllite-Schist-Gneiss

Which of the following minerals is found in impact craters only?

Stishovite

List the 4 tectonic settings where igneous activity occurs:

Subduction zones, Midocean ridges, Continental rifts and Hotspots

Where would you expect coal to be deposited?

Swamps

A conglomerate sample consists of well-rounded clasts of granite, angular clasts of mica-schist and individual mineral fragments derived from granite and mica-schists. What can you infer about the source region of the sandstone? (Check all that apply)

The basin where sandstone was deposited received sediments from both igneous and metamorphic terrains. Igneous terrain was closer to the source than the metamorphic terrain. The combined source region dominant mineralogy (i.e. considering both terrains together) is quartz, feldspar, biotite and muscovite.

Shock metamorphism is associated with:

Ultrahigh P/High T

What does red shale tell us about its depositional conditions?

The environment of depositions was exposed the atmosphere

Formation of migmatite is an indication of:

The rock has just entered the zone of melting the Earth

Which of the following statements are true about sedimentary formations?

They are arranged in layers, They are mappable and They may contain sedimentary structures

Which of the following rocks is not derived from an igneous rock melt?

Tuff

An igneous rock containing <45% SiO2 is called:

Ultramafic rock

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?

Ultramafic<Mafic<Intermediate<Felsic

A metamorphic rock contains the minerals coesite and diamond. What can you infer about the P/T conditions of the rock?

Very high P

Vesicles in vesicular textures are remnants of:

Volatile passages in an igneous rock

Fragmental texture is formed from:

Volcanic ash and Volcanic rock debris

In a flux-induced melting, which of the following can act as flux?

Water vapor, Carbon-dioxide and Sulphur dioxide

How would you get a conglomerate from a granite?

Weathering

Sedimentation

Weathering Erosion Deposition

Arrange in correct order the set of processes leading to a clastic rock formation.

Weathering-Erosion-Deposition-Burial-Compaction-Cementation

A magma that is rich in volatiles is called:

Wet magma

Rock exhumation

brings rocks from depths to surface- applies to ion/sedi/meta rocks)