Geological Structure

Question 1

What are the three major geological regions in India?

Answer 1

1. The peninsular region
2. The extra peninsular region
3. The Indo-Gangetic plain

Question 2

Archean, Purana, Dravidian and Aryan are classification of?

Answer 2

The rock system of India

Question 3

Assertion: Archean rock system comprises the oldest rocks.
Reason: They were the first to be formed at the time of cooling and solidification of the upper crust around 4000 million years ago.

Answer 3

Both are true, and the reason for the assertion is correct.

Question 4

What is ‘Fundamental Complex’ or the ‘Basement Complex’?

Answer 4

Archean rocks like gneiss and schists often underlie the strata formed subsequently. Hence they are sometimes called Fundamental or Basement complex.

Question 5

What is the underlying rock system of the Himalayas?

Answer 5

Archean rocks forms the bulk of high ranges and the back bone of mountain system.

Question 6

What is Archean rock system?

Answer 6

Archean rock system refers to rocks formed prior to the Cambrian period i.e around 4000 million years ago.

Question 7

What is Dharwar Rock System?

Answer 7

Dharwar rock system refers to one of the oldest metamorphic deposits in India. These rocks are of both sedimentary and igneous origin.
Most rocks of this system are so metamorphosed, that they are practically indistinguishable from their primitive forms.
These rocks were deposited in three major cycles:
The earliest one over 3,100 million years ago and the latest one about 2,300 million years ago.
They were metamorphosed around 1,000 millions years ago.

Question 8

What is the economic significance of Dharwar rocks?

Answer 8

Dharwar rocks are economically the most important rocks because they posses valuable minerals like high grade iron ore, manganese, lead, gold, copper, mica, slate, quartzite, etc…