Correct Answer: Option 4 – Halite and Pyroxene

Cleavage describes the way a mineral breaks along its plane of weakness. These planes of weakness can be described as where the atomic bonding between atoms in the crystal structure is weak at those points causing the mineral break when stressed much like a stack of papers when drop will spread off in individual sheets. Cleavage, being related to structure, is important at times in the correct identification of a mineral's symmetry. Remember, cleavage must obey the symmetry of the mineral and must be parallel to a possible crystal face. A mineral of the isometric symmetry class can either have no cleavage or at least three directions of identical cleavage that form a closed three dimensional polygon. A mineral of a uniaxial class (trigonal, tetragonal or hexagonal) will potentially have a cleavage perpendicular to the dominant axis and/or prismatic cleavage of either 3, 4 or 6 directions respectively, running parallel to the axis. Other cleavage directions are possible, but will always be controlled by the symmetry of the crystal. A biaxial mineral, those belonging to orthorhombic, monoclinic or triclinic classes, cannot have more than two identical cleavage directions. The amphibole groups of minerals are distinguished primarily by cleavage angle. The angle may also help identify the type of cleavage. Three identical directions of cleavage in one mineral can only be cubic cleavage, rhombic cleavage or prismatic (forming six sided prisms). If the angle between cleavage faces is 90 degrees, then the cleavage is cubic. If the angle is 60 degrees, then the cleavage is prismatic. Also, if the angle is something else and there are three identical cleavages, then the cleavage is rhombic.

Correct Answer: Option 2 – lava that cooled quickly on Earth's surface

"Igneous" comes from the Latin for fire, and all igneous rocks began as hot, fluid material. This material may have been lava erupted at the Earth's surface, or magma (unerupted lava) at shallow depths, or magma in deep bodies (plutons). Rock formed of lava is called extrusive, rock from shallow magma is called intrusive and rock from deep magma is called plutonic

Origin

"fire-formed rocks"

Crystallize from molten material:

• Magma - below the Earth's surface
• Lava - erupts onto the Earth's surface through a volcano or crack (fissure)

Lava cools more quickly because it is on the surface.

Cooling Rates

Cooling rates influence the texture if the igneous rock:

• Quick cooling = fine grains
• Slow cooling = coarse grains

Correct Answer: Option 1 – the oceanic crust has a greater density

Subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. A subduction zone is an area on Earth where two tectonic plates move towards one another and subduction occurs. Subduction zones involve an oceanic plate sliding beneath either a continental plate or another oceanic plate. Subduction zones are often noted for their high rates of volcanism, earthquakes, and mountain building. This is because subduction processes result in melt of the mantle that produces a volcanic arc as relatively lighter rock is forcibly submerged. Hot mantle at the core-mantle boundary rises and cool mantle sinks causing circular cells to form. At points where two downward moving convecting cells meet (cold mantle sinking), convection can occur taking the oceanic crust below either continents or other oceanic crust. Continental crust tends to override oceanic crust because it consists of less dense granite compared to the basalt of the oceanic crust.

Correct Answer: Option 3 – Mass movement

Mass movement is the down slope movement of earth materials under the influence of gravity. The detachment and movement of earth materials occurs if the stress imposed is greater than the strength of the material to hold it in place.

Incorrect Answers

Tides are the rising of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans Tides cause changes in the depth of the marine and estuarine water bodies and produce oscillating currents known as tidal streams, making prediction of tides important for coastal navigation. The changing tide produced at a given location is the result of the changing positions of the Moon and Sun relative to the Earth coupled with the effects of Earth rotation and the bathymetry of oceans, seas and estuaries. More generally, tidal phenomena can occur in other systems besides the ocean, whenever a gravitational field that varies in time and space is present

Glacial erosion produces U-shaped valleys and are characteristically so shaped. Because the lower (and more horizontally inclined) part of the U is far underwater, the visible walls may rise vertically for hundreds of feet from the water’s edge, and close to the shore the water may be many hundreds of feet deep. When allowed to spread out, a glacier erodes the landscape uniformly, but when confined within valley walls it tends to deepen and widen the valley floor. The commonly V-shaped stream valley is converted to a U-shaped valley because the U-shape provides the least frictional resistance to the moving glacier. Because a glacier has a much greater viscosity and cross section than a river, its course has fewer and broader bends, and thus, the valley becomes straighter and smoother. The valley walls may be almost vertical and may be striated by boulders dragged by the glacier, and the valley floor may be covered with till or moraines.

Correct Answer: Option 2 – burial and compaction

Sediments originate from weathering and erosion of rocks on land. Most of this sediment eventually gets transported and deposited in the sea, near river mouths or further offshore. Sediments cannot continue to build up indefinitely unless the surface on which they are deposited is slowly sinking – areas where this is happening are sometimes called Sedimentary Basins

As layers are piled one upon another, the sediments beneath are buried, sometimes by hundreds of meters of sediment above. The weight of the layers of sediments, compacts (squashes down) the sediment grains. Minerals deposited from water in the spaces between the sediment grains gradually cement them together. Compaction happens when sediments are deeply buried, placing them under pressure because of the weight of overlying layers. This squashes the grains together more tightly.

Correct Answer: Option 4 – transform plate boundary and hot spot

The major damage due to earth quake is expected near a transform plate boundary and a hotspot, because these are the zones which can easily move and hence, lead to huge damage.

Divergent plate boundary, convergent plate boundary are 2 different types of transform plate boundaries. Hence, options 1, 2 and 3  are incorrect.

Correct Answer: Option 3 - Plattsburgh

As represented by the diagram above Plattsburgh in New York State has the greatest risk of earthquake damage.

Correct Answer: Option 2 – heat energy has been creating convection currents in the Earth's interior

The tectonic plate movement occurs due to the heat energy creating convection currents in the Earth’s interior.

It is not the gravitational force of the moon, or the earth’s rotation on its axis or the change in the tilt of the axis of the earth which has lead to the tectonic plate movement. Hence, options 1, 3 and 4 are incorrect.

Correct Answer: Observable characteristics which could be used to identify this rock sample as gneiss are

• Deformation
• The rock is foliated

Correct Answer: Two minerals found in gneiss that contain iron and magnesium are:

• Mica

• Augite