Geological Evolution — Practice Quiz

A tableland that has risen due to block faulting

Step 1: A 'horst' is a geological term referring to a raised block of the earth's crust that has been pushed upward between fault lines. Step 2: The Peninsular Plateau is described as a horst because it has behaved as a rigid, inflexible block throughout its geological history. Step 3: It has been subjected to vertical movements and block faulting, rising above the surrounding areas without being folded or significantly deformed. Step 4: A valley between two fault lines is called a 'rift valley' or 'graben' — this is the opposite of a horst. Step 5: Fold mountains (like the Himalayas) are form

Archean

Step 1: India has four geological eras — Archean, Purana, Dravidian, and Aryan. Step 2: The Archean corresponds to the Early Pre-Cambrian era. It contains the first-formed rocks of the Earth, primarily gneisses and granites with no fossils. Step 3: The Purana corresponds to the Late Pre-Cambrian era. Step 4: The Dravidian covers from the Cambrian to the middle Carboniferous period (400-570 million years ago). Step 5: The Aryan is the most recent Indian era, covering from the Upper Carboniferous to the present (400 million years ago to present).

Coal

Step 1: The Gondwana rocks were formed during the Upper Carboniferous period when the Peninsular Plateau experienced crustal movements. Step 2: These movements created basin-shaped depressions which trapped countless terrestrial plants and animals. Step 3: Over millions of years, these organic materials were buried and compressed to form coal deposits. Step 4: This is why Gondwana rocks are famous for coal deposits, found mainly in the Damodar, Mahanadi, and Godavari valleys. Step 5: Gold is found in the Dharwar system, iron ore in the Dharwar and Cuddapah systems, and limestone in the Vindhya

Gondwanaland

Step 1: Before the Himalayas were formed, the Tethys Sea lay between two large ancient landmasses. Step 2: Angaraland was located to the NORTH of the Tethys Sea. It roughly corresponds to modern-day Asia and Europe. Step 3: Gondwanaland was located to the SOUTH of the Tethys Sea. It included the Indian subcontinent, Africa, South America, Antarctica, and Australia. Step 4: Rivers from both Angaraland and Gondwanaland deposited sediments into the Tethys Sea, which were later folded to form the Himalayas. Step 5: Laurasia was another name for the northern supercontinent, similar to Angaraland —