This cache is about types of rock found on Earth namely, igneous, sedimentary and metamorphic rock.
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1) Identify the type of rock at GZ and explain your answer?
2) What is the estimate height of the largest rock at GZ?
3) Are both Rocks at GZ the same type of rock?
There are three main types of rocks:
- Metamorphic Rock
- Igneous Rock
- Sedimentary Rocks
Metamorphic Rock
This is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. There are two basic types of metamorphic rocks. Foliated metamorphic rocks such as gneiss, phyllite, schist, and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure. Non-foliated metamorphic rocks such as hornfels, marble, quartzite, and novaculite do not have a layered or banded appearance.
With the Cape Fold Mountains stringing from Cape Town through to KZN and in many cases science has found that the central core of many mountain belts is made of metamorphic rocks.
Igneous Rock
The word is derived from the Latin word ignis meaning fire. Igneous rock is formed through the cooling and solidification of magma or lava.
The Karoo is the main point of interest of Igneous Rock as scientist believe that much of the Karoo basin was formed by volcanic reaction. Coming closer to Port Elizabeth and investigating the Cape Fold Belt of southern South Africa we find that it due to the repeated episodes of tectonic deformation on continental lithosphere that there are pockets of Igneous rock.
Sedimentary Rocks
These are types of rock that are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles (detritus) to settle in place.
The Cape Fold Mountain Range is composed predominantly of quartzitic Sandstone. This is a clastic sedimentary rock composed of sand-size grains of mineral, rock, or organic material. It is composed of sand-size grains of mineral, rock, or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains. Sandstone is one of the most common types of sedimentary rock and is found in sedimentary basins throughout the world. It is often mined for use as a construction material or as a raw material used in manufacturing. In the subsurface, sandstone often serves as an aquifer for groundwater or as a reservoir for oil and natural gas.
Van Stadens Nature Reserve finds itself in a very unique position with having a few valleys where the Van Stadens River flows to the Lady Slipper Mountain practically right next door. Then there are some areas which some believe could have been a river bed many years ago. If you look carefully you will see ample evidence that points this area as being part of the Cape Fold Mountain Range.
References:
http://geology.com/
https://en.wikipedia.org/wiki/Cape_Fold_Belt
https://www.sanparks.org/assets/docs/parks_addo/geology.pdf
https://www.ru.ac.za/media/rhodesuniversity/content/geology/documents/SciFest%202015%20Rhodes%20Field%20Trip.pdf
https://www.earth.ox.ac.uk/~oesis/field/#sedimentary
http://sajg.geoscienceworld.org/content/100/3/195
http://karoospace.co.za/dolerite-karoos-fracking-game-changer/