How Golda Meir, Indira Gandhi, and Margaret Thatcher Wrought a New Standard of Leadership. It is surely time to recognize what an immense improvement has been wrought in world standards of governance by the rise of female national leaders.
Shield volcanoes, the third type of volcano, are built almost entirely of fluid lava flows. Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior's shield.
Two types of lava flows, pahoehoe and aa, are different textural forms of otherwise identical lava. The smooth-textured pahoehoe lavas (left) are formed by stable upwelling of gas-poor lava, whereas the hackly-surfaced aa flows are produced during eruptions with high lava fountaining of gas-rich magma.