Archean

How To Use Archean In A Sentence

• _ -- The whole formation is Archean and Primary (with a few modern plutonic outbursts), and chiefly consists of granite, felspar, quartz, gneiss, schists, amphibolite and other Archean rocks, with Primary sandstones and limestones in the basin of Lake Nyasa (a great rift depression), the river Shiré, and the regions within the northern watershed of the Zambezi river. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"
• The answers to questions about early life on Earth are preserved in the oldest rocks, and Canadian earth scientists include some of the world's best Archean geologists and laboratories equipped to study Archean rocks.
• The rocks dated back into the Archean eon, before 2.5 billion years ago.
• There is strong geological evidence that the only "dry land" prior to the early Archean was scattered basaltic islands (sitting over mantle plume "hot spots") similar to the Hawaiian islands. Ancient Predator Revealed!
• With the exception of the post-Karoo igneous intrusive formation and the recent thin alluvia along the major river valleys, the strongly consolidated rocks of the Archean Basement Complex and the Karoo system underlie practically all of Swaziland and limit the groundwater development potential of the country. Water profile of Swaziland
• Mobile belts of various ages seem to have stitched Africa's Archean cratons together by Himalayan-style continental collisions.
• The Proterozoic, Archean and Hadean are often collectively referred to as Precambrian Time, and sometimes also as the Cryptozoic. Table of geologic time - The Panda's Thumb
• During the Archean Eon life started and was dominated by one-celled prokaryotic life forms. Geologic time
• However, most Archean volcanic rocks occur as deformed and fault-fragmented packages termed greenstone belts.
• Precambrian divisions such as the Proterozoic and the Archean were conventionally eras but are now often referred to as eons.