短语词组短語oceanic c rift valley system 大洋裂穀系mid d oceanic rift 大洋中穀mid oceanic rift 大洋中穀;中央裂穀oceanic rift valley system 大洋裂穀系oceanic rift system 海洋裂穀系;大洋斷裂系mid -oceanic rift 洋中穀 返回 oceanic rift