Calthemites
Calthemites are secondary deposits, i.e it forms from chemical alterations or weathering from a primary rock. Their formation and shape are like speleothems, in particular stalactites, but due to the strict definition of the word calthemites cannot be called speleothems. Calthemites can also form as flowstones.
Limestone is a sedimentary rock that is dominantly composed of the calcium-bearing carbonate minerals calcite and dolomite. Calcite is chemically calcium carbonate. This rock undergoes weathering and chemical alteration, allowing calthemites to form as mainly white calcium carbonate. Impurities such as iron oxide (rust) can sometimes give the calthemites a red or orange tinge. When water (leachate) rich in CaCO3 evaporates, it leaves behind the calcium carbonate.
Calthemite flowstone
Calthemite stalactite
QUESTIONS
Hopefully the short lesson is enough to help you answer the following! Exit the building towards Jalan Tun Perak and look above at the elevated trackway. Notice the calthemite deposits and answer the below.
- Looking at the elevated trackway, notice some white appear. What inference can you make of the nature of the concrete used?
- Describe the shape of the calthemite deposit:
- Directly beneath the platform - note the precise locations they are formed.
- Those in more exposed areas
- Give an inference as to why they are different and explain their formation in each environment.
- Are the calthemites deposited as stalactites or flowstones?
- A photo to prove your visit would be great.
I do not expect PhD level answers, nor do I overly care about wrong answers. As long as you have a good log about your experience and a photo, and you try to answer the questions as best as possible it is fine.