Final answer:
a) Two types of "natural cements" are silica cement and calcium carbonate cement.
b) The type of cement commonly used in concrete to make sidewalks and buildings is calcium carbonate cement.
c) The type of cement that would more easily erode in an acidic environment is calcium carbonate cement.
Step-by-step explanation:
The effects of heat, pressure, and cementation on sediments undergoing lithification are as follows:
Heat: Heat causes the mineral grains in sediments to vibrate more, which can break down the bonds between the grains and allow them to move closer together. This can lead to the formation of denser, more compact rocks.
Pressure: Pressure, which increases with depth of burial, can also cause the mineral grains in sediments to move closer together. In some cases, pressure can be so great that it can cause the grains to fuse together, forming a solid rock.
Cementation: Cementation is the process by which minerals precipitate from solution and fill the pores between the grains in sediments. This can bind the grains together and make the rock more resistant to erosion.
There are two main types of "natural cements":
Silica cement: Silica cement is formed by the precipitation of silica (SiO2) from solution. Silica cement is common in sandstone and other sedimentary rocks.
Calcium carbonate cement: Calcium carbonate cement is formed by the precipitation of calcium carbonate (CaCO3) from solution. Calcium carbonate cement is common in limestone and other sedimentary rocks.
Calcium carbonate cement is more easily eroded in an acidic environment than silica cement. This is because calcium carbonate is soluble in acids, while silica is not.
So, Heat and pressure cause the mineral grains in sediments to move closer together, making the rock more dense and compact.
Cementation is the process by which minerals precipitate from solution and bind the grains together, making the rock more resistant to erosion.
There are two main types of natural cements: silica cement and calcium carbonate cement.
Calcium carbonate cement is more easily eroded in an acidic environment than silica cement.