The geology of the Zion and Kolob canyons area includes nine known exposed
formations, all visible in Zion National Park in Utah, United States, and
representing about 150 million years of mostly Mesozoic-aged sedimentation.
Part of the Grand Staircase, the formations exposed in the Zion and Kolob
area were deposited in several different environments that range from warm
shallow seas, streams, and lakes to large deserts and dry near-shore
environments. Subsequent uplift of the Colorado Plateaus exposed these
sediments to erosion by swifter streams that preferentially cut through
weaker rocks and jointed formations. Much later, lava flows and cinder
cones covered parts of the Zion area. Zion National Park is situated on an
elevated plateau that consists of sedimentary formations that dip very
gently to the east. This means that the oldest strata are exposed along the
Virgin River in the Zion Canyon part of the park and the youngest are
exposed in the Kolob Canyons section. The plateau is bounded on the east by
the Sevier Fault Zone, and on the west by the Hurricane Fault Zone.
Weathering and erosion along north-trending faults and fractures influence
the pattern of landscape features associated with canyons in this
stream-incised plateau region.
Read the rest of this article:
http://en.wikipedia.org/wiki/geology_of_the_Zion_and_Kolob_canyons_area
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Today's selected anniversaries:
1768:
The first edition of the Encyclopædia Britannica was published.
(
http://en.wikipedia.org/wiki/Encyclop%E6dia_Britannica)
1922:
The Irish Free State came into existence, one year after the signing of the
Anglo-Irish Treaty.
(
http://en.wikipedia.org/wiki/Irish_Free_State)
1957:
The Project Vanguard attempt to launch the United States's first satellite
was thwarted by a launchpad explosion.
(
http://en.wikipedia.org/wiki/Project_Vanguard)
1989:
Marc Lépine killed 14 women in the École Polytechnique Massacre in
Montreal, leading to Canadian gun control laws.
(
http://en.wikipedia.org/wiki/%C9cole_Polytechnique_Massacre)
1992:
The Babri Mosque was destroyed by members of the Vishwa Hindu Parishad and
associated groups, believing it was built on the birthplace of Rama.
(
http://en.wikipedia.org/wiki/Babri_Mosque)
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Wikiquote of the day:
"To be a catalyst is the ambition most appropriate for those who see the
world as being in constant change, and who, without thinking that they can
control it, wish to influence its direction." -- Theodore Zeldin
(
http://en.wikiquote.org/wiki/Theodore_Zeldin)