Figure 10-16: R I V U X G
Mare Basalt This 1.53-kg (3.38-lb) specimen of mare basalt was brought back by the crew of Apollo 15. Gas must have dissolved under pressure in the lava from which this rock solidified. When the lava reached the airless lunar surface, the pressure on the lava dropped and the gas formed bubbles. Some of the bubbles were frozen in place as the rock cooled, forming the holes on its surface. (Figure 9-18a shows a sample of basalt from Earth.)
Mare Basalt This 1.53-kg (3.38-lb) specimen of mare basalt was brought back by the crew of Apollo 15. Gas must have dissolved under pressure in the lava from which this rock solidified. When the lava reached the airless lunar surface, the pressure on the lava dropped and the gas formed bubbles. Some of the bubbles were frozen in place as the rock cooled, forming the holes on its surface. (Figure 9-18a shows a sample of basalt from Earth.)
(NASA)