Historical Geology Understanding Our Planet\'s Past
in the crust quickly healed as batches of fresh magma bled through giant fis- sures and poured onto the surface, creating a magm ...
functional until about 3 billion years ago, when the formation of the crust was nearly complete. Much information about the earl ...
and tell of the earliest history of Earth, when the crust first formed some 4.2 billion years ago. Among the oldest rocks are th ...
through the thin crust. Great floods of dark basaltic lava spilled onto the sur- face,giving the Moon a landscape of giant crate ...
longer), it transferred some of its angular momentum to the Moon, flinging it outward into a widening orbit. Eventually, the Moo ...
THE ATMOSPHERE For the first half billion years, while Earth was spinning wildly on its axis and sur- face rocks were scorching ...
though millions of tons of coal rained down from the heavens. Perhaps these carbon-rich meteorites bore the seeds of life, which ...
face blanketed the entire planet with suspended sediment much like the Mar- tian dust storms of today (Fig. 11). Huge lightning ...
mountain slopes and the sides of large meteorite craters, gouging out deep canyons in the rocky plain.When the rains ceased and ...
ocean did not reach its present concentration of salts until about 500 million years ago.The warm seas were heated from above by ...
required for such a random event would involve billions of years. Moreover, evidence gathered from ancient rocks on Earth, the M ...
for a site in Western Australia where it fell to Earth in 1969.The meteorite held lipidlike organic compounds able to self-assem ...
early in the history of life. Furthermore, no new life-forms are being created today either because the present chemical environ ...
remained hot, ring molecules of sulfur atoms in the atmosphere would block out solar ultraviolet radiation. Otherwise, the first ...
Free ebooks ==> http://www.Ebook777.com the first simple organisms appeared to have arrived soon after conditions on Earth be ...
T his chapter examines the earliest history of Earth, its evolving life- forms, and the formation of continents. The first 4 bil ...
Historical Geology TABLE 2 THE GEOLOGIC TIME SCALE Age (Millions First Era Period Epoch of Years) Life-Forms Geology Holocene 0. ...
interval, the planet experienced a restlessness that might have been a major fac- tor in the emergence of life so early in the h ...
thick gre w on the surface of a clay-rich soil, becoming the first life on land some 2.6 billion years ago. The stromatolite col ...
Free ebooks ==> http://www.Ebook777.com Although the Archean spans almost half of Earth’s history, its rocks rep- resent less ...
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