Question: where can helium be found in the world

title: Helium
text: Most helium on Earth is a result of radioactive decay . Helium is found in large amounts in minerals of uranium and thorium , including cleveite , pitchblende , carnotite and monazite , because they emit alpha particles ( helium nuclei , He ) to which electrons immediately combine as soon as the particle is stopped by the rock . In this way an estimated 3000 metric tons of helium are generated per year throughout the lithosphere . In the Earth 's crust , the concentration of helium is 8 parts per billion . In seawater , the concentration is only 4 parts per trillion . There are also small amounts in mineral springs , volcanic gas , and meteoric iron . Because helium is trapped in the subsurface under conditions that also trap natural gas , the greatest natural concentrations of helium on the planet are found in natural gas , from which most commercial helium is extracted . The concentration varies in a broad range from a few ppm to more than 7 % in a small gas field in San Juan County , New Mexico . 

Answer: answer: Helium is found in large amounts in minerals of uranium and thorium , including cleveite , pitchblende , carnotite and monazite , because they emit alpha particles ( helium nuclei , He ) to which electrons immediately combine as soon as the particle is stopped by the rock . In the Earth 's crust , the concentration of helium is 8 parts per billion . In seawater , the concentration is only 4 parts per trillion .There are also small amounts in mineral springs , volcanic gas , and meteoric iron .Because helium is trapped in the subsurface under conditions that also trap natural gas , the greatest natural concentrations of helium on the planet are found in natural gas , from which most commercial helium is extracted . The concentration varies in a broad range from a few ppm to more than 7 % in a small gas field in San Juan County , New Mexico .