Category Archives: Earth Science

Also known as Geology, Geosciences, etc. It is a science that deal with Geologic materials and processes which made them. A multidisciplinary field in which also includes Geophysics, Hydrology, Structure and Civil Engineering and many more.

Earth Science

Late Heavy Bombardment

The Late Heavy Bombardment and its Impact on the Terrestrial Planets

Sanuja Senanayake1, Jenna Sie1, Brendan Visser1 and Cassie Vocke1
1Geology Undergraduate Students: Fall 2014, University of Calgary.

Abstract

The Late Heavy Bombardment (LHB) is a hypothetical astrophysical event which occurred in our Solar System 4.1 to 3.8 billion years ago. At this time, an increased flux of impacting materials hit the Earth, Moon and other terrestrial planets of the inner Solar System. This has been suggested as the source for the increased number of crater impacts seen on the lunar surface, Venus, and Mars, and inferred to have struck all the inner terrestrial planets; preserved evidence has yet to be discovered on Earth. Several theories have been proposed to explain the crater formations, however the focus will be on the two most accepted theories: the Nice Model and Planet V Hypothesis. The preservation of craters from the LHB is best seen on the Moon due to the lack of plate tectonics, minimal erosion and deposition. Analyzing the surface of the Moon can help us understand the impact that the LHB had on the inner solar system. A lunar timescale is currently being modified, and when calibrated with radiometric dates from Martian samples, a timescale for Mars and other planetary bodies could be developed to verify if the LHB was a synchronous event. The LHB was early in Earth’s evolution and the contribution of extraterrestrial material to the planet is thought to have affected it in different ways; this includes the development of the atmosphere, biosphere and hydrosphere. The LHB is important not only to explain the sudden increase in crater evidence but also to help confirm the current geochemical properties of the terrestrial planetary system as seen today.

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Earth Science

Thin Section Sketches

Thin section sketches are drawings that represent what you observed. But most of us (students, researchers and professors) are not artistically inclined. Even if you are good at drawing diagrams, you still have to empathize key features when drawing a thin section sketch. Here are some tips and tricks for making a good (if not perfect) thin section sketch.

Kyanite - PPL
Photomicrograph of Kyanite – PPL
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Earth Science

Few tips for new Geoscience students

Fault steps
Fault steps

Even before we go into minute details on being a successful Geoscience student, let me explain why we use “Geoscience” as opposed to “Earth Science” or “Geology”. Geology can be loosely defined as the study of solid Earth and the processes which the Earth evolve. But it has grown into a multidisciplinary field with several different specializations. Geology itself has few different sub specializations such as hydrology, environmental, petroleum, engineering, mining and precious metal, geochemistry, etc. Additionally we have two major sectors; Geology and Geophysics. Hence I think the best way to describe all of these sub sections is to use the term “Geoscience”.

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Earth Science

Pictures from field school

The pictures are from the Carlin Canyon, Nevada Field School instructed by Dr. Charles Henderson and Dr. Benoit Beauchamp at the University of Calgary. However, this page has no affiliation to the professors or the university. This is a personal (Sanuja Senanayake) collection of images. The GPS reading are taken either from the built-in GPS locator in the camera or from field notes. I found that the location information can be highly inaccurate. One should not use the information on this page for any type of field work. The images are posted purely for entertainment.

Conglomerate

Location: 40°44’05.8″N 116°01’18.3″W
Elevation: 1478.70 m
Image direction: 100.73° (true direction)

Image: Click on the image for high resolution version.

Conglomerate formed by cyclothems.
Conglomerate formed by cyclothems.

Features: Conglomerate formed as a result of cyclothems.

Cross-bedding

Location: 40° 44′ 10.26″ N 116° 1′ 2.946″ W
Elevation: 1641.20 m
Image direction: 51.06° (true direction)

Image: Click on the image for high resolution version.

Crossbeds indicating marine environment.
Crossbeds indicating marine environment.

Features: Inclined layers with dipping indicating paleocurrents.

Paleosols

Location: 40° 44′ 6.678″ N 116° 1′ 9.48″ W
Elevation: 1653.70 m
Image direction: 66.78° (true direction)

Image: Click on the image for high resolution version.

Paleosols identified by roots and root traces.
Paleosols identified by roots and root traces.

Features: Roots and rootlets are indicative of paleosols. The Paleosols are formed under subareal exposure type environments.

Lava Rocks

Location: TBA
Elevation: TBA
Image direction: 2.05° (true direction)
Image: Click on the image for high resolution version.

Rocks formed by lava flows
Rocks formed by lava flows

Rocks formed by lava flows II
Rocks formed by lava flows II

Features: Ropy texture of this lava formation is indicative of pahoehoe lava.

Chert

Location: 40° 44′ 8.016″ N 116° 1′ 9.114″ W
Elevation: 1654.20 m
Image direction: 62.95° (true direction)

Image: Click on the image for high resolution version.

Chert sticking out of the outcrop.
Chert sticking out of the outcrop.

Chert at another location.
Chert bands sticking out of the outcrop.
Chert bands sticking out of the outcrop.

Features: Chert is more weather resistant than the outcrop surrounding them. Therefore it will stick out and easy to identify. Generally all cherts are harder than the surrounding Geologic material.

Contact between Formations

Location: 40° 43′ 46.764″ N 116° 1′ 0.006″ W
Elevation: 1663.10 m
Image direction: 89.70° (true direction)

Image: Click on the image for high resolution version.

Contact between two Formations.
Contact between two Formations.

Features: Different lithoologies will often have different weathering colours and patterns.

Misidentify a contact

Location: 40° 43′ 20.394″ N 116° 1′ 16.794″ W
Elevation: 1504.70 m
Image direction: 249.06° (true direction)

Image: Click on the image for high resolution version.

This looks like a contact, but it is not.
This looks like a contact, but it is not.

Features: This is not a contact but rather a fracture within the same formation. The difference in weathering colour may have been caused by the lower part being exposed to more fluid runoffs(?) from the fracture.

Fluvial Deposits

Location: TBA
Elevation: NA
Image direction: TBA
Image: Click on the image for high resolution version.

Fluvial deposits - Hoodoos
Fluvial deposits – Hoodoos

Features: Poorly sorted clasts from almost all Formations in the region. Lose sediments, friable and extremely poor bedding (almost no bedding). Formed as a result of weathering and erosion of other formations. May indicate a paleo river formation. Highly matrix supported with sandy size matrix particles.

Resistant (cliff forming) and Recessive

Location: 40° 43′ 40.8″ N 116° 1′ 10.1″ W
Elevation: NA
Image direction: 9.59° (true direction)

Image: Click on the image for high resolution version.

Formations : Resistant and (cliff) recessive outcrops.
Formations : Resistant and (cliff) recessive outcrops.

Features: Even from a distance we can interpret some Geological formations. In this example, we can say that at least two major formations based on the cliff forming and recessive units. Often Geologists scans the area before climbing to the outcrop of interest. In this picture we are about 1 km (or may be bit less) away from the outcrops shown.

Lose (non-outcrop type) Carbonate

Location: 40° 44′ 9.54″ N 116° 0′ 15.426″ W
Elevation: 1617.40 m
Image direction: 58.65° (true direction)

Image: Click on the image for high resolution version.

Lose sediments are an erosional feature.
Lose sediments are an erosional feature.

Features: Lose materials like these red carbonate pieces can be used to determine where the actual outcrop may be; up the slope!

Searching for outcrops like mountain goats

Location: 40° 43′ 3.3″ N 116° 0′ 9.306″ W
Elevation: 1569.70 m
Image direction: 167.06° (true direction)

Image: Click on the image for high resolution version.

Searching for outcrops.
Searching for outcrops.

Features: None that can be identified at this scale.

Miscellaneous

Chert in an unknown location (same area).
Chert in an unknown location (same area).
Crossbeds in an unknown location (same area).
Crossbeds in an unknown location (same area).