Hadean vs Plutonian

Hadean

adj
  • Pertaining to Hades or hell. 

  • Of, or relating to the geological eon. 

name
  • The Hadean eon; part of the Precambrian supereon, spanning from around 4.6 to 4 billion years ago. 

Plutonian

adj
  • Of or relating to Pluto, the Greek and Roman god of the underworld; demonic, infernal. 

  • Pertaining to the astrological influence of Pluto, formerly regarded as a planet. 

  • Synonym of plutonic (“of, pertaining to, or supporting plutonism, the theory that the rocks of the Earth were formed in fire by volcanic activity, with a continuing gradual process of weathering and erosion, then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again”) 

  • Of or relating to the dwarf planet Pluto. 

  • Synonym of plutonic (“of or pertaining to rocks formed deep in the Earth's crust, rather than by volcanoes at the surface of the Earth”) 

  • Of, relating to, or having characteristics associated with the underworld; dark, gloomy; mournful. 

noun
  • A person under the astrological influence of Pluto, formerly regarded as a planet. 

  • A proponent of plutonism; a plutonist. 

  • An (imaginary) inhabitant of the dwarf planet Pluto. 

How often have the words Hadean and Plutonian occurred in a corpus of books? (source: Google Ngram Viewer )