UPCAT REVIEWER: GENERAL SCIENCE (GEOLOGY)

Diastrophism

• this pertains to the movement of all solid parts of the earth

Upward forces
Downward forces
Sideward forces

A. Direction of forces and movements they produce:

Upward forces (Compression)

• cause the local or widespread rising or uplift of the crust

Downward forces (Tensional)

• cause by the local or widespread sinking subsidence of the crust.

Sideward forces (Shearing)

• cause by the horizontal motion of the crust called thrust. Large masses of rocks slide and slip against each other into new positions.

Folding
Faulting

B. Effects of diastrophism:

Folding

• occurs when the crust crumples or wrinkles due to compressions or pushes from opposite directions. As the crust is crumpled, the rock strata become tilted.

• Himalayas, Alps, etc.

Faulting

• occurs when the rock masses of the crust are pulled apart forming cracks or fractures on the crust. The rock layers slide and slip against each other along the breaks.

• Sierra Nevada and Great Rift Valley in Africa.

Continental drift Theory
Seafloor Spreading
Plate tectonic Theory

C. Causes of diastrophism:

Continental drift Theory

• proposed by Alfred Wegener

• according to him 200 million years ago, there was only a single super continent called Pangaea situated at the center of the equator. It broke up into pieces which slowly moved away from each other.

• The pieces formed the continents today.

Seafloor Spreading

• Proposed by Harry Hess

• five years after Wegener discovery a break or rift was found at the middle of the ridge running along its length where basaltic magma wells out to the surface. This basaltic magma solidified forming a new crust it pushes the old crust causing the ocean floor to spread.

Plate tectonic Theory

• it proposed that the lithosphere is divided into six more plates.

• The plate may be composed of the continental crust on top of the oceanic crust alone. These plates are slowly, but nevertheless continually in motion.

• is a scientific theory that explains how major landforms are created as a result of Earth’s subterranean movements.

Divergent boundary
Convergent boundary
Transform boundary

3 Plate boundaries:

Divergent boundary

• an area where two plates move apart leaving a gap between them. The gap formed is immediately filled up with molten material that wells up from lower mantle.

Convergent boundary

• an area where two plates move toward each other. As the plates collide, the leading edges of one plate is bent downward allowing it to slide beneath the other.

Transform boundary

• this is the area where two plates move past each other, sliding scraping and deforming the edges of the continents.

Volcanism

• the building up of landforms due to volcanic activities is rapid and process is dramatic.

Active volcano
Dormant volcano
Extinct volcano

Classification of Volcanoes based on activities: (A D E)

Active volcano

• Currently erupting or has erupted in recent history (within the last 10,000 years)

Dormant volcano

• Has not erupted in a long time, but might erupt again in the future

Extinct volcano

• Has not erupted for thousands of years and is unlikely to erupt again.

Shield Volcano
Cinder-Cone Volcano
Composite Volcano
Caldera

Classification of Volcanoes Based on Shape / Structure (form): (S C C C)

Shield Volcano

• Broad, gently sloping sides like a warrior’s shield; formed by fluid lava flows.

Cinder-Cone Volcano

• Small, steep-sided volcano made from pyroclastic fragments or cinders.

Composite Volcano

• Large, symmetrical with layers of lava and ash; very explosive.

Caldera

• Large crater formed when a volcano collapses after a major eruption.

Hawaiian
Strombolian
Vulcanian
Plinian

Classification of Volcanoes Based on Eruption Style: (H S V P)

Hawaiian

• Calm, gentle lava flows from shield volcanoes

• low gas, very fluid (runny) lava.

Strombolian

• Frequent, small to moderate explosions

• lava is thicker and erupts in short bursts

Vulcanian

• Short, violent explosions of viscous lava and ash

• more powerful than Strombolian

Plinian

• Extremely powerful, high-reaching eruption columns, heavy ashfall, pyroclastic flows.

Earthquakes

• any movement or shaking of the ground.

Tectonic

• earthquake caused by the movement of tectonic plates or shifting of faults.

Volcanic

• earthquake caused by the movement of molten magma from deep under the earth’s crust up.

Epicentre

• The point directly above the focus on the Earth’s surface.

• On the ground (Surface)

Focus

• Also called Hypocenter.

• The exact point inside the Earth where the earthquake starts (where rocks first break or move).

• Below the earth’s surface.

Tidal wave / tsunami

• large mass of water displaced by an earthquake and

  may be destructive

Intensity

• is measured in terms of its effect to a man, its damage to manmade structures and changes in natural objects and land surfaces.

Magnitude

• measures the energy released by the earthquake. It provides information about the severity of earthquake apart from damage it caused.

Richter Scale

a scale from 1 to 10 used to measure the magnitude of

earthquakes according to the amount of energy released, with a

higher number indicating stronger tremors.

Mercalli Scale

• a scale for measuring the intensity of earthquakes, ranging from 1 to 12, in which 1 denotes a weak earthquake and 12 one that causes complete destruction.

Seismograph

• an instrument that detects the presence of an earthquake and measures and records its magnitude.

Seismogram

• a record of an earthquake made by a seismograph.

Igneous
Sedimentary
Metamorphic

Kinds of Rocks: (I S M)

Igneous rocks
Igneous Intrusive
Igneous Extrusive

• _ Heavy, unlayered, dark rocks formed by the cooling and hardening of molten materials called magma.

• Cooled magma/lava.
  - ___ formed from magma that did not reach surface of the earth. These are generally light-colored and have large crystals
  - ___ formed from lava that cooled down and solidified on the surface of the earth. Rapid cooling caused small crystals to form

Sedimentary rocks
Clastic
Chemical
Organic

• formed by the accumulation and consolidation of mineral and particulate matter deposited by the action of water, wind, glacial ice.

• Formed by compaction and cementation of sediments like sand, mud, or small rocks.
  -____ Made of rock fragments (sand, silt, pebbles) that are compacted and cemented.
  -____ Formed when dissolved minerals crystallize out of solution.
  -____ Formed from the remains of living things.
  

Metamorphic rocks
Metamorphism

• are very hard rocks formed when igneous or sedimentary rocks are changed by heat, pressure, and/or chemical processes.

• This process is called _.

Clastic
Chemical
Organic

Types of Sedimentary rocks: (C C O)

Talc
Gypsum
Calcite
Fluorite
Apatite
Orthoclase
Quartz
Topaz
Corundum
Diamond

Moh’s scale of hardness: (1-10) (T G C F A O Q T C D)

Weathering

• is the process of breaking down rocks into smaller particles through physical (mechanical), chemical, or biological means.

Erosion

• is the process by which weathered rock particles are loosened, picked up, and transported from one place to another by natural agents like water, wind, ice, or gravity.

Crust
Mantle
Outer core
Inner core

What are the four major layers of the earth?

Crust

• Outermost layer of the Earth; where we live

• Irregular thickness:

  • ~5 km beneath oceans (oceanic crust)

  • ~30 km beneath continents (continental crust)

• Composed mainly of lighter rocks:

  • Basalt (oceanic crust)

  • Granite (continental crust)

Mantle

• Located beneath the crust

• Extends to a depth of about 2,900 km

• Made of silicate rocks rich in iron and magnesium

• Divided into two parts:

  • Upper _: more rigid, behaves elastically on short time scales

  • Lower _: solid, but flows over long geological timescales

Outer core

• Lies between 2,900 km and 5,150 km deep

• Composed mainly of liquid iron and nickel

• Movements within this layer generate Earth’s magnetic field

Inner core

• Center of the Earth

• Extends from 5,150 km to 6,371 km depth

• Despite extreme heat, it is solid due to high pressure

• Composed primarily of iron, with nickel and lighter elements

Lithosphere

• Thickness: About 10 to 200 km

• Composed of: Crust and the uppermost mantle

• Characteristics:

  • Rigid and brittle

  • Broken into tectonic plates

• Varies in thickness:

  • Thinner at oceanic ridges

  • Thicker beneath older oceanic and continental regions

Asthenosphere

• Location: Beneath the lithosphere, from ~100 to 350 km deep

• Characteristics:

  • Plastic/ductile behavior (flows slowly)

  • Allows tectonic plates to move above it

• Composition: Similar to upper mantle, mainly peridotite (rich in silicate minerals)

Mesosphere

• Location: Below the asthenosphere, extends to ~2,900 km deep

• Characteristics:

  • Strong, rigid rocks

  • Deforms slowly under high heat and pressure

• Composition: Silicate minerals that change structure with increasing depth