Learning Module 2 Lesson 2
Rocks and Sedimentary Rocks
- Rock-forming Minerals
- List the rock-forming minerals.
- Answer: calcite, gypsum, feldspar, pyrite, feldspars, gold, quartz, diamond amphiboles, micas, olivine, garnet, calcite, and pyroxenes
- Which rock-forming minerals are common in igneous rocks?
Answer: Silicate type of minerals are the most common minerals found in igneous rocks which include silicate minerals like feldspars (plagioclase feldspar, potassium feldspar)
.c. Which rock-forming minerals are common in sedimentary rocks?
Answer: They include quartz, K-feldspar, and muscovite.
- From which mineral group does most of these minerals originate?
Answer: Silicate type of minerals
- Rock Cycle.
- Use your own words to describe the sequence of processes that result in igneous rocks. Describe a specific example of a sedimentary rock becoming an igneous rock.
Answer: Igneous rock or any form of crystalline rocks are usually formed by the processes of cooling and solidification of molten earth material. More importantly, it is vital to understand that Igneous rocks, in most cases, constitute one of the three primary groups of rocks, the two others include the metamorphic and sedimentary. It is a fact that igneous rock is unique in terms of structure and composition. A good example of a sedimentary rock becoming an igneous rock can be viewed as a particular layer of sandstone, which got subducted below a continent, and it melted later it is cooled.
- Use your own words to describe the sequence of processes that result in sedimentary rocks. Describe a specific example of sedimentary rock, becoming a new type of sedimentary rock.
Answer: There are four primary processes which are associated with the formation of a clastic sedimentary rock. It is formed through the process of weathering or erosion, which is mainly caused mainly by wave friction and also the vast transportation of sediment. These sediments get carried away by water current, then the deposition and compaction process starts when it settles, forming this type of rock. It is vital to note that this type of rock is usually broken into smaller bits by weathering and erosion later fragments get cemented together to create sedimentary rock. An example of a sedimentary rock becoming a new type of sedimentary rock happens in a certain condition as the conglomerate is then broken into smaller sand-like particles, which are later recemented to form sandstone.
- Use your own words to describe the sequence of processes that result in metamorphic rocks. Describe a specific example of a sedimentary rock becoming a metamorphic rock.
Answer:
Metamorphic rocks are mostly formed from the type of rocks in that they are created through heat and pressure. It is vital to state that these rocks are not made from molten rock. Historically, Earth movements tend to cause rocks to get deeply buried or get compacted. Additionally, Sedimentary rocks tend to become metamorphic in their rock cycle when they have put under high heat and a lot amount of pressure. The high temperatures usually originate from the Earth’s tectonic plates when they move around, thus releasing heat. Later on, they tend to collide, to form mountains and also metamorphose.
- Discuss how igneous, sedimentary, and metamorphic rocks can be used to tell us about Earth’s history.
Answer:
Igneous rocks tell of past volcanic episodes and can also be used to age-date certain periods in the past.
Sedimentary rocks tell us, humans, about past environments at Earth’s surface.
Metamorphic rocks tend to explain to people concerning plate tectonic movements and how the continents were shoved together and pulled apart.
- If you were a Paleolithic human and had to choose between limestone and Chert as the material for an ax head, which would you select? Why?
Answer: I would choose Chert mainly because it very hard sedimentary rock and lighter compared to limestone that is usually found in nodules in limestone.