Highlights of a Grand Canyon Timeline, by science writer Chris Clarke

[BurtWorm]

http://faultline.org/index.php/site/comments/timeline/

Timeline

Time expressed in years before present day.

~2,000,000,000: Paleoproterozoic era, possibly during the Orosirian Period. Sediments are laid down in a shallow sea teeming with the newly evolved Cyanophyta, or blue-green algae.

~1,700,000,000: Probably during the Stratherian period, after the evolution of multicellular life, intense heat and pressure cook the above sediments into metamorphic rock, the Vishnu Schist. Intrusions of volcanic rock, the Zoroaster Granite, occur at about this time.

~1,200,000,000: During the Stenian period, as the supercontinent Rodinia is assembling, a layer of dolomite sediments out atop the Vishnu schist and Zoroaster granite. This will be called the Bass Limestone. After a relatively brief period of time, perhaps only a few million years, the sea from which the Bass Limestone was deposited recedes, and river deltas along the advancing shore lay down mud, silt, and sand that will become the Hakatai shale. These wetlands are home to stromatolites, large reef-like structures made by colonial cyanobacteria. The Hakatai emerges above sea level, is eroded away in part along with any overlying layers, and then re-submerged, after which sands are deposited —these will become the Shinumo Quartzite — and then tidal flat sediments upon the sands, which become the Dox Formation.

...

~550,000,000: The region is once again slowly submerged in ocean water. This ocean water now has multicellular animals living in it, some of them, such as trilobites, brachiopods, and crinoids, with hard shells. As the shore advances over the landscape the Tapeats Sandstone is laid down, consisting of coarse beach sand and conglomerated cobbles.


...

~1,800,000: Volcanoes erupt, forming the youngest rock in the Grand Canyon. The eruptions dam the river at least a dozen times over the next 1.4 million years, causing gigantic reservoirs to form. Some of the lava dams are 1,000 feet high, with the full force of the Colorado flowing over them in impossibly huge waterfalls as it cuts troughs through them. The Canyon reaches nearly its current depth about now.

...

~1,200: The Ancestral Puebloan people build remarkable and sturdy edifices in the area.

138: John Wesley Powell rafts the Colorado through the Canyon singlehanded.

113: Much land around the Grand Canyon is declared a preserve by President Benjamin Harrison.

99: Grand Canyon National Monument is established by Theodore Roosevelt.

88: Grand Canyon National Park is signed into existence by Woodrow Wilson.

...

6: President George W. Bush, an avowed fundamentalist Christian and smirking denier of scientific fact, is sworn into office.

3: The National Park Service approves the gift-shop sale of a book claiming the Canyon is just 6,010 years old while denying other new books shelf space. Park Service brass stonewalls in defense of the decision, despite sharp criticism from the non-ignorant community, until the present day.

[Bunny]

1. That was very interesting. Thank you, BurtWorm.

It's mind-boggling that the NPS continues to peddle that ridiculous book, isn't it?

:hi:

[BurtWorm]

2. Indeed, Bunny.

( Happy New Year! :toast: )