Hadean
The Hadean () is a geologic eon of the Earth pre-dating the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the ICS, 4 billion years ago. , the ICS describes its status as ""informal"". Geologist Preston Cloud coined the term in 1972, originally to label the period before the earliest-known rocks on Earth. W. Brian Harland later coined an almost synonymous term, the "Priscoan period", from "priscus", the Latin word for "ancient". Other, older texts simply refer to the eon as the Pre-Archean.
Haida argillite carvings
This first phase, named Haida I, existed from about 1820 to 1830. The second phase began in 1830 and was titled the Western Period. This is when argillite carving began to incorporate Western elements and themes. Kaufman refutes the idea that this phase is influenced by European and Euro-American buyers who wanted to purchase Haida carved argillite in Western themes. She also disagrees with the theory Barbeau and Erna Gunther proposed: that Western themed argillite carving was inspired by whalers' scrimshaw. Kaufmann interprets the move toward Western images in the 1830s as the Haida's receptivity to European culture, and the social desire to incorporate the Western mode of life more fully into their own world. Phases one and two are similar in that none of the items carved are sacred; instead all of the argillite carvings produced between 1820 and 1865, the approximate end date for the second period, are utilitarian pieces and completely secular in nature. The third period Haida II, is marked by a return to Haida inspired images, theme and styles and begins five years after the end of the second, in 1870. Although this return to more traditional images has been interpreted as stabilization in Haida society due to the decrease of whalers and traders in the region, Kaufmann believes the substitution was actually caused by the disintegration of social and artistic regulation. Because the Haida population had been decimated due to contact elements such as disease, increased mobility, and missionary influences the traditional rules which regulated the production of culturally important objects and images began to degrade. According to Kaufmann, the proliferation of sacred or respected imagery or objects in a medium such as argillite was in actuality "a loosening within the traditional social structure"