Key Terms List

A list of geologic terms that pertain to this blog.

Sometimes a hiker turns into a geologist or sometimes a hiker is just trying to read a travel blog that is sprinkled with geology. I wanted to include a list of geological words for easy reference for those who are the latter. All words will be in alphabetical order. Some terms will require longer explanations and will link you to other pages. This is no way a comprehensive geological term list, but the list is composed of geological terms that are already on or will occur in my blog.

---

Geological History is the best and first place that we will start. I just want to make sure that we (hikers and geologist alike!) are all on the same time scale before building our vocabulary.

Geological history follows the major events that occur during Earth's past. The image below shows the classification.

A simpler snapshot of geological history. On left, it shows the types of fossils that can be found in this time period, while moving across depicts some eons, eras and periods. The numerical time scale can be found on the right.

Geological history is divided into a geological time scale, meaning that it is created through chronologically dating of the different rock layers. After formation of the Earth, geological time is broken into eons. These are the largest chunks of time, which are Precambrian and Phanerocoic. Precambrian can be further broken done into main categories seen as Hadean, Archean and Proterozoic. Eons are divided into smaller units called eras, which include divisions of Archean and Proterocoic, Paleozoic, and Mesozoic. Eras continue to be broken town into periods. For example, the Paleozonic is divided into numerous layers that include Cambrian, Ordovician, ect. Finally, there are finer subdivisions of time called epochs.

---

Key Term List: (In alphabetical order)

• Bed(s): layers of sedimentary rocks that are distinctly different from above or below layers of sedimentary rocks

• Bedding: describes the layering that occurs between sedimentary and sometimes metamorphic rocks, can occur when one distinctly different layer is deposited on an older layer

• (Inter)bedding: occurs when beds of rocks are between other beds of rocks

The visually distinctive layers of rocks can be seen (beds) and the layering between the beds is called bedding.

• Bedrock: solid layer of rock under loose surface (sand, gravel, soil, clay) of Earth

• Deformation: is caused by stress (force) applied to a certain area or rocks, in particular, the stress on rocks can vary which includes changes in temperature, moisture, buildup or even gravity

• Depositional Environment: This is a specific type of place where sediments are deposited, like lakes, channels, streams, or deep ocean. It is categorized into three main types: continental where sediments are deposited on land or in fresh water, transitional where sediments are deposited where there is influence of both fresh water or air and marine water, and marine where sediments are deposited in only sea water

• Eon(s): a major devision of geological time

• Epoch(s): a division of time that is a subdivision of an era

• Era: a subdivision of geological time that divides an eon into smaller time

• Erosion: gradual removal and transportation of materials from the Earth's crust due to natural processes like wind, water, or rain

• Floodplain: a flat area of lower elevation ground that is adjacent to a river that can experience flooding

• Formation: basic unit that geologist use to categorize and map layers of rocks; the rock unit must be unique enough in physical appearance to see the difference from other rock units, can also be rocks that are inter-layered together

• Geology: a science that deals with Earth's physical structure, substance, history and all the processes that act on it

• Geologist: scientist who studies the materials, processes and past of the Earth

A couple of geologists in their nature environment, including yours truly at the bottom in black.

• Geological History: time period that is arranged based off main events and different rock layers

• Igneous Rocks: [x] click here to be taken to the classification of rocks

• Metamorphic Rocks: [x] click here to be taken to the classification of rocks

• Outcrop: a visible exposure of bedrocks or deposits

An outcrop on the side of the road.

• Plate Tectonics: a scientific theory that explains structure of the Earth's crust that describes large-scale motion of seven large plates and movements of a larger number of smaller plates

The divisions of the Earth's surface can be seen as the different "plates" described in plate tectonics.

• Rock: solid mineral material forming part of the surface of earth that can be either outside or inside of surface [x] click here to be taken to the classification of rocks

• Rock Strata: layer of sedimentary rocks or igneous rocks formed at Earth’s surface that have consistent characteristics that make it unique

• Sediments:

• Sedimentary: [x] click here to be taken to the classification of rocks

• Sandstone: [x] click here to be taken to the classification of rocks

• Unconformity: A gap in geological record that can be seen through observing the surfaces of two rock bodies that constitute a substantial break which can be where one surface was experiencing erosion, sea level variations or crustal deformation.

An unconformity is represented with a red line that shows the irregular contacts between the rocks.

• Uplift: a vertical change in elevation of Earth's surface due to natural causes

• Weathered: worn out due to long exposure to the air, seasoned by exposure to the weather

This depicts the process of weathering on a rock over time.