Atmosphere of Earth primarily hydrogen. There were probably simple hydrides such as those now found in the gas giants (Jupiter and Saturn), notably water vapor, methane and ammonia. Outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth by huge asteroids, produced the next atmosphere, consisting largely of nitrogen plus carbon dioxide and inert gases. A major part of carbon-dioxide emissions dissolved in water and reacted with metals such as calcium and magnesium during weathering of crustal rocks to form carbonates that were deposited as sediments. Water-related sediments have been found that date from as early as 3.8 billion
S-80-class submarine weapons and sensors, which their government decided not to fund. DCNI then proposed a cheaper option called the S-90B, an S-70 "Agosta"-class submarine with limited improvements which was again rejected by the French but which was exported to Pakistan. Meanwhile, Spain faced the same problem in replacing their "Daphné"s, known as the "Delfín" class in Spanish service, as part of Plan ALTAMAR. Bazán (later Izar, and then Navantia) started on a new design but when it started to look like the S-80, it was agreed to collaborate in a joint venture based on the French S-80. This joint design was