Geology project: Detailed description of Chemical and mechanical weathering and Metamorphism

Geology project: Detailed description of Chemical and mechanical weathering and Metamorphism

Project 3

For project 3, please provide short answers for the following:

  • Describe the main processes of mechanical weathering, and the types of materials that are produced when mechanical weathering predominates
  • Describe the main processes of chemical weathering, and the products of chemical weathering of minerals such as feldspar, ferromagnesian silicates, and calcite
  • Explain the type of weathering processes that are likely to have taken place to produce a sand sized sediment deposit
  • Discuss the relationships between weathering and soil formation and the origins of soil horizons
  • Explain the geological carbon cycle, and how variations in rates of weathering can lead to climate change
  • Describe the differences between cobbles, pebbles, sand, silt, and clay
  • Explain the relationship between clast size and the extent to which clasts can be transported by moving water or by wind
  • Apply your understanding of the features of sedimentary rocks, including grain characteristics, sedimentary structures, and fossils, to the interpretation of past depositional environments and climates
  • Explain the importance of and differences between groups, formations, and members

 

Project 4

For project 4, please provide short answers for the following:

  • Summarize the factors that influence the nature of metamorphic rocks
  • Describe the mechanisms for the formation of foliation in metamorphic rocks
  • Classify metamorphic rocks on the basis of their texture and mineral content,
  • Describe the various settings in which metamorphic rocks are formed and explain the links between plate tectonics and metamorphism
  • Summarize the important processes of regional metamorphism
  • Summarize the important processes of contact metamorphism and metasomatism
  • Explain the difference between relative and absolute age-dating techniques
  • Summarize the history of the geological time scale and the relationships between eons, eras, periods, and epochs
  • Describe the types of unconformities
  • Describe some applications and limitations of isotopic techniques for geological dating.

Processes of chemical weathering

Ice. The formation of ice in the horde of minuscule splits and joints in a rock\’s surface gradually pries it separated more than a great many years. Frost wedging results when the formation of ice extends and develops the breaks, severing pieces and sections. Ice wedging is best in those atmospheres that have numerous patterns of freezing and thawing. Frost heaving is the cycle by which rocks are lifted vertically from soil by the formation of ice. Water freezes first under stone pieces and stones in the dirt; the continued freezing and defrosting of ice bit by bit pushes the stones to the surface.

Exfoliation. If a huge intrusion is brought to the surface through tectonic inspire and the erosion of overlying rocks, the confining weight over the intrusion has been delivered, yet the weight underneath is actually being applied, constraining the stone to extend. This cycle is called unloading. Because the external layers grow the most, breaks, or sheet joints, build up that equal the bended external surface of the stone. Sheet joints become surfaces along which bended bits of rock loosen up, uncovering another surface. This cycle is called exfoliation; large adjusted landforms (generally meddlesome rocks) that outcome from this cycle are called exfoliation domes. Examples of exfoliation vaults are Stone Mountain, Georgia, and Half Arch in Yosemite National Park.

Friction and impact. Rocks are additionally separated by friction and repeated impact with other stone sections during transportation. For instance, a stone part conveyed along in a river\’s ebb and flow continuously ricochets against other sections and the waterway base and inevitably is broken into littler pieces. This cycle happens likewise during transportation by wind and frigid ice.

Other processes. Less significant specialists of mechanical weathering incorporate the burrowing of creatures, plant roots that develop in surface splits, and the digestion of specific minerals, for example, metal sulfides, by bacteria. Daily temperature changes, particularly in those regions where temperatures can shift by 30 degrees centigrade, bring about the expansion and contraction of minerals, which debilitate rocks. Extreme temperature changes, for example, those delivered by woodland fires, can constrain rocks to break.

Weathering processes that are likely to have taken place to produce a sand sized sediment deposit

Regional transformation happens when rocks are covered somewhere down in the outside layer. This is commonly connected with convergent plate limits and the formation of mountain ranges. Since internment to 10 km to 20 km is required, the territories influenced will in general be enormous.

Most regional transformation happens inside continental outside layer. While rocks can be transformed at profundity in many regions, the potential for transformation is most noteworthy in the underlying foundations of mountain ranges where there is a strong probability for entombment of generally youthful sedimentary stone to incredible profundities.

A model would be the Himalayan Range. At this continent-continent convergent limit, sedimentary rocks have been both pushed up to incredible statures (almost 9,000 m above ocean level) and furthermore covered to extraordinary profundities.

Factors that influence the nature of metamorphic rocks

At a maritime spreading edge, as of late framed maritime covering of gabbro and basalt is gradually moving endlessly from the plate limit. Water inside the outside is compelled to ascend in the region near the wellspring of volcanic warmth, and this attracts more water from farther out, which inevitably makes a convective framework where cold seawater is brought into the covering and afterward out again onto the ocean bottom close to the edge.

The entry of this water through the maritime covering at 200° to 300°C advances transformative reactions that change the first pyroxene in the stone to chlorite and serpentine. Since this transformation happens at temperatures well underneath the temperature at which the stone initially shaped (~1200°C), it is known as retrograde transformation.

The stone that structures thusly is known as greenstone in the event that it isn’t foliated, or greenschist in the event that it is. Chlorite and serpentine are both “hydrated minerals” implying that they have water (as Goodness) in their concoction recipes. When transformed sea outside is later subducted, the chlorite and serpentine are converted into new non-hydrous minerals (e.g., garnet and pyroxene) and the water that is delivered relocates into the overlying mantle, where it contributes to motion liquefying.

Processes of regional metamorphism

At a subduction zone, maritime outside is constrained down into the hot mantle. But since the maritime covering is presently moderately cool, particularly along its ocean bottom upper surface, it doesn’t warm up rapidly, and the subducting rock stays a few several degrees cooler than the encompassing mantle. An extraordinary sort of transformation happens under these high-tension however moderately low-temperature conditions, creating an amphibole mineral known as glaucophane, which is blue in shading, and is a significant component of a stone known as blueschist.

On the off chance that you’ve never observed or even known about blueschist, it’s to be expected. Is astonishing that anyone has seen it! Most blueschist structures in subduction zones, continues to be subducted, transforms into eclogite at around 35 km profundity, and afterward in the end sinks profound into the mantle — gone forever.

Regional transformation additionally happens inside volcanic-curve mountain extents, and as a result of the additional warmth related with the volcanism, the geothermal inclination is commonly somewhat more extreme in these settings (somewhere close to 40° and 50°C/km). Thus higher evaluations of transformation can occur nearer to surface than is the situation in other territories.