zion canyon geology mystery

Zion Canyon

zion canyonZion Canyon Utah USA is a very deep but narrow canyon in red Navajo Sandstone rock, with big wall climbs of over 2,000 feet (600 meters).

The distance between the cliff faces averages only 1000 feet (300 meters) at ground level.

One of the deepest parts of the Zion gorge is known as the Temple of Sinawava, a natural amphitheater with shear walls going down to a depth of 3,000 feet (900 meters).

zion canyon The narrows

Geology suggests that the canyon was formed through the Virgin River water erosion. But the water volume of the Virgin River is normally small, although flash floods and flooding does occur.

There is even a part of the Zion Canyon known as The Narrows and The Subway. The distance between the Zion Narrows cliff faces averages only 20 feet (6 meters).

The canyon floor is surprisingly very flat.

Geology suggests the level surface is due to a huge rock landslide from The Sentinel rock face blocking the Virgin River and creating a centuries long dam in the canyon.

The flat valley floor of modern Zion Canyon owes its origin to a 286 million m3 rock avalanche at 4.8 ka arising from the catastrophic collapse of a nearly 900-m-high wall of predominantly Navajo Sandstone Formation.

zion canyon geology mystery

… Zion Canyon was blocked over a distance of 3.3 km, damming the Virgin River and creating a lake. At its high-stand, Sentinel Lake may have covered more than 6 km2, including all of Zion Canyon to The Narrows, but this water level was short-lived as incision of slide debris lowered the breach elevation to ~1345 m. There Sentinel Lake stood relatively stable for ~700 yr until filling with sediment.
Dynamics and legacy of 4.8 ka rock avalanche that dammed Zion Canyon, Utah, USA | The Geological Society of America (link to PDF)

How did the Virgin River remain flowing for a very long time (millions of years?) during what geology describes as uplift that pushed rock from sea level up to 10,000 feet?

Zion Canyon

zion canyon Three Patriarchs 3
When did this massive rock slide event occur? What events triggered it?

zion canyon the subway water river erosion tunnels

Has water erosion created the Zion Canyon? How were The Narrows formed or not eroded wider?

How were the Three Patriarchs also eroded at their perpendicular angle to the main canyon direction?

Other puzzling and interesting erosion peaks, canyons or tunnels in the Zion National Park include The Kolob Canyons and The Zion Subway.

Why are the top layers of the red Navajo Sandstone made of shale and other material? Could this material have been dumped or deposited at the same time as the material that dammed the canyon?