Hawaii hotspot created at least 129 volcanoes, more than 123 of which are extinct volcanoes, seamounts, and atolls, four of which are active volcanoes, and two of which are dormant volcanoes. They can be organized into three general categories: the Hawaiian archipelago, which comprises most of the U.S. state of Hawaii and is the location of all modern volcanic activity; the Northwestern Hawaiian Islands, which consist of coral atolls, extinct islands, and atoll islands; and the Emperor Seamounts, all of which have since eroded and subsided to the sea and become seamounts and guyots (flat-topped seamounts). Hawaiian volcanoes are characterized by frequent
Extinct radionuclide found in nature, so they are known as extinct radionuclides. Their former existence is inferred from a superabundance of their stable decay products. Examples of extinct radionuclides include iodine-129 (the first to be noted in 1960, inferred from excess xenon-129 concentrations in meteorites, in the xenon-iodine dating system), aluminium-26 (inferred from extra magnesium-26 found in meteorites), and iron-60. The Solar System and Earth formed from primordial nuclides and extinct nuclides. Extinct nuclides have decayed away, but primordial nuclides still exist in their original state (undecayed). There are 253 stable primordial nuclides, and remainders of 33 primordial radionuclides that have very