็HOW LIMESTONE CAVES ARE FORMED
A limestone cave or cavern is a natural cavity that is formed underneath the Earth’s surface that can range from a few metres to many kilometres in length and depth.
Most of the world’s caves, including those at the Cradle of Humankind, are formed in porous limestone. Over millions of years, acidic groundwater or underground rivers dissolve away the limestone, leaving cavities which grow over time.
Early life forms appeared in the oceans about 3.8-billion years ago. These were single-celled, blue-green algae, called cyanobacteria, which made their own food through photosynthesis, releasing oxygen into the atmosphere in the process.
็HOW LIMESTONE CAVES ARE FORMED A limestone cave or cavern is a natural cavity that is formed underneath the Earth’s surface that can range from a few metres to many kilometres in length and depth.Most of the world’s caves, including those at the Cradle of Humankind, are formed in porous limestone. Over millions of years, acidic groundwater or underground rivers dissolve away the limestone, leaving cavities which grow over time.Early life forms appeared in the oceans about 3.8-billion years ago. These were single-celled, blue-green algae, called cyanobacteria, which made their own food through photosynthesis, releasing oxygen into the atmosphere in the process.
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