Notes, summaries, assignments, exams, and problems for Geology

Models of the Earth's Interior

Geochemical Model

• Crust: Up to the Mohorovičić discontinuity (35 km)
  • Continental: Granite and gneiss
  • Oceanic: Basalt
• Mantle: Up to the Gutenberg discontinuity (2,900 km). Composed of peridotite.
• Core: Central sphere (up to 6,378 km). Composed of iron and nickel.

Geodynamic Model

• Lithosphere: Crust and upper mantle. Composed of solid rocks.
  • Continental: 100–200 km (less dense)
  • Oceanic: 50–100 km (more dense)
• Asthenosphere: Solid but plastic rocks. Up to 660 km.
• Mesosphere: Solid but plastic rocks. Up to 2,900 km.
• Endosphere (Core):
  • Outer core: Up to the Lehmann discontinuity (5,100 km). Molten rocks.
  • Inner core: Remainder of the core. Solid rocks.

Isostasy

The behavior of the Earth's crust, as if it were floating on denser... Continue reading "Earth's Internal Structure and Geological Processes" »

Understanding Water Pollution

Water pollution is any chemical, physical, or biological change in water quality that has a damaging effect on anything living that consumes that water. When humans drink contaminated water, they often have health problems. Water contamination can also make it unsuitable for its intended use.

Common Types of Water Pollutants

There are several kinds of water pollutants. The first of these are disease-causing agents. These include bacteria, viruses, protozoa, and parasitic worms that are incorporated from sewage systems and raw sewage.

Oxygen-Consuming Agents

A second category of water pollutants are oxygen-consuming agents; these are residues that can be decomposed by oxygen-consuming bacteria. When the bacterial populations... Continue reading "Impacts and Causes of Water Contamination" »

Sunspot

The most visible manifestation of solar activity.

Solar Activity

All the sunspots, bursting events, and associated phenomena.

Solar Cycle

The nearly periodic 11-year change in solar activity (i.e., changes in the number of sunspots, flares, and other associated manifestations).

Wolf Number

A measure of the amount of sunspots, used to quantify solar activity.

Solar Wind

Solar material flowing into interplanetary space; the Sun's atmosphere expanding radially outwards in all directions.

Climate Change

A change in the statistical distribution of weather patterns.

Weather

The state of the atmosphere at any given place and time.

Climate

The average (mean) of weather parameters over a long period of time.

Meteoroid

A small rocky or metallic body traveling... Continue reading "Essential Astronomical and Meteorological Definitions" »

The Wilson Cycle: Earth's Dynamic Plate Movement

The Wilson Cycle describes the cyclical opening and closing of ocean basins and the fragmentation and reassembly of continents through plate tectonic processes. It typically involves several stages:

1. Continental Fragmentation and Rift Formation

   Plate dynamics generate tension that can cause a large continental mass to fracture along an axis. As the separation of plates continues, the lithosphere sinks, forming an intercontinental rift valley.

2. Formation of an Expanding Ocean

   If the rift is near a sea, the valley will flood, and a narrow sea will be formed. As the plates continue to separate, a mid-ocean ridge develops along the center, and new oceanic lithosphere expands.

3. Ocean Reduction and Continental

Structure of the Earth

Earth consists of four concentric layers: inner core, outer core, mantle, and crust. The crust is made up of tectonic plates, which are in constant motion. Earthquakes and volcanoes are most likely to occur at plate boundaries.

Inner Core

The inner core is in the center and is the hottest part of the Earth. It is solid and made up of iron and nickel with temperatures reaching 5,500ºC.

Outer Core

The outer core is the layer surrounding the inner core. It is a liquid layer, also made up of iron and nickel. Temperatures are similar to the inner core.

Mantle

The mantle is the widest section of the Earth, with a thickness of approximately 2,900km. It is made up of semi-molten rock called magma.

Crust

The crust is the outer layer of... Continue reading "Structure of the Earth and Plate Tectonics: A Comprehensive Guide" »

What is the Environment?

We can define the environment as the space in which some kind of natural exchange that makes life possible takes place. The environment is not only the space itself but also the different forms of life that inhabit it. That is, if we were speaking of space only, we would be referring merely to a spatial location. On the other hand, the concept of environment expands this idea to include everything related to life developing in that space. Today, the environment is a topic very much in vogue because of the debate generated around its care and how human activity contributes increasingly more rapidly to damage it.

The environment is nothing other than the medium, precisely the place or space in which different life-related... Continue reading "Defining the Environment and Understanding Human Impact" »

• Pollution is the addition of a substance or an agent to an environment by human activity, at a rate greater than that at which it can be rendered harmless by the environment and which has an appreciable effect on the organism within it.

• Basically… contamination of nature which affects living organisms.

• Substances exposed to the atmosphere and littering by humans.

POINT SOURCE POLLUTION (Coming from a direct source)

• The pollutants are coming from clear identifiable sources: sewage into a river.

• Easier to see who is polluting.

• Easier to manage and monitor.
  

NON-POINT SOURCE POLLUTION (NPS)

• Release of pollutants from numerous sources: car fumes, etc.

• Almost impossible to detect the origins of the pollutants.

• Rain can collect various forms of nitrates and

Collapse

Collapse is the reduction in wood size during drying before fiber saturation. It manifests as a corrugated surface due to crushed wood tissues and sometimes internal lens-shaped cracks. Collapse occurs in some wood species when dried slowly at high temperatures or humidity, or during rapid outdoor drying. It's more intense on radial cut faces than tangential ones. This defect causes significant wood loss during surfacing and reduces mechanical strength. Tangential shrinkage is greater than radial shrinkage, often separating wood tissues parallel to the weaker radial parenchyma cells. The pith is also susceptible to damage, developing cracks and crevices. In eucalyptus, avoid sawing the pith to achieve good quality dried products.

Drying... Continue reading "Wood Defects and Degradation" »

Understanding the Deep Ocean: Vessels and Instruments

Oceanographic Vessels

Conshelf

Conshelf: A diver who lives and operates both inside and outside a submarine refuge for an extended period.

Alvin

Alvin: A manned deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts.

Aluminaut

Aluminaut: The world's first aluminum submarine. This experimental vessel, an 80-ton, 15.5-meter (51 ft) manned deep-ocean research submersible, was built by Reynolds Metals Company to promote the utility of aluminum.

Essential Oceanographic Instruments

Water Bottle

Water Bottle: A container used to hold water, liquids, or other beverages for consumption.

Reversing Thermometer

Reversing