In Andhra Pradesh, Dharwar types of rocks are found in:

Key Points

• The Chittoor and Nellore regions in Andhra Pradesh are known for their significant deposits of Dharwar rocks.
• Dharwar rocks are among the oldest rock formations in India, dating back to the Precambrian era.
• These rock types mainly consist of metamorphosed sedimentary and volcanic rocks.
• The presence of these ancient rocks indicates a rich geological history and the potential for mineral deposits in the region.

Additional Information

• Dharwar Craton
  • The Dharwar Craton is a part of the Indian Shield and is famous for its Archean rock formations, which are among the oldest geological features on Earth.
  • It is named after the town of Dharwar in Karnataka and spans a large area covering parts of Karnataka and Andhra Pradesh.
  • These cratons are known for their rich mineral resources, particularly gold, iron ore, and other metals.
  • The rock formations within the Dharwar Craton have provided valuable insights into the Earth's early crustal development and tectonic history.
• Precambrian Era
  • The Precambrian era covers almost 90% of Earth's geological history, spanning from the formation of the Earth about 4.6 billion years ago to the start of the Cambrian period, approximately 541 million years ago.
  • It is divided into three eons: the Hadean, Archean, and Proterozoic.
  • Most of the Earth's continental crust was formed during this era, and it witnessed the emergence of the first simple life forms.
  • Studying Precambrian rocks is crucial for understanding the Earth's early environment and the evolution of life.
• Metamorphic Rocks
  • Metamorphic rocks are formed from pre-existing rocks (igneous, sedimentary, or other metamorphic rocks) that have been transformed by heat, pressure, and chemically active fluids.
  • Common examples include slate, schist, and gneiss.
  • These rocks are characterized by their distinct foliation or banding patterns, which result from the alignment of mineral grains under directional pressure.
  • Metamorphic processes play a key role in the rock cycle, contributing to the formation of economically important mineral deposits.