Mountain Building Basics
This first stage of a major mountain belt involves building up thick stacks of sedimentary or volcanic rock that will later be deformed
What is the accumulation stage?
In this type of fold, rock layers bend upward into an arch, and the oldest rocks are in the center
What is an anticline?
This Nevada park lies in the Basin and Range Province and shows classic alternating high ranges and sediment-filled basins created by normal faulting
What is Great Basin National Park?
This Wyoming park is a classic example of a normal fault-block range rising abruptly above Jackson Hole
What is Grand Teton National Park?
Both Lehman Cave in Great Basin and Mammoth Cave in Kentucky formed when groundwater dissolved this carbonate rock
What is limestone?
This stage is the main mountain-building event when intense folding, faulting, and crustal deformation occur
What is the orogenic stage?
In this fold, layers bend downward into a trough, and the youngest rocks are in the center
What is a syncline?
The repeating pattern of high fault-block mountains and low sediment-filled valleys seen in Nevada and eastern California is called this
What is Basin and Range topography?
The Teton Range has been uplifted more than 30,000 feet relative to the valley block along this kind of fault
What is a large normal fault?
Just like the glaciated landscapes of Rocky Mountain and Yosemite, repeated alpine glaciations in Grand Teton carved these broad, flat-floored valleys out of former V-shaped stream valleys
What are U-shaped valleys?
After orogeny, this stage stretches the crust, causes normal faulting and uplift of fault blocks, and helps create Basin-and-Range topography
What is crustal extension and block faulting (the block-faulting/uplift stage)?
This kind of fault forms under tensional stress when the hanging wall moves down relative to the footwall, stretching the crust
What is a normal fault?
Because streams in the Great Basin never reach the ocean and end in playas or salt lakes, the region is described as having this type of drainage.
What is interior drainage?
Sequoia and Kings Canyon National Parks expose a huge Mesozoic body of intrusive igneous rock that crystallized miles underground; it’s called this
What is a granite batholith?
Sequoia and Kings Canyon are dominated by a granite batholith, while Mount Rainier in Washington is built mostly of this intermediate-composition volcanic rock
What is andesite?
This term describes the stable interior of a continent, usually made of very old crystalline rocks
What is the craton?
This low-angle type of reverse fault pushes older rocks up and over younger ones and is common in the Appalachians
What is a thrust fault?
At the base of steep mountains in Death Valley, these fan-shaped deposits form where fast-moving streams suddenly slow down on the flat basin floor
What are alluvial fans?
Redwood National Park sits on this type of tectonic setting, where sediments and bits of oceanic crust are scraped off a subducting plate and plastered onto the continent
What is an accretionary wedge?
Redwood’s rising coastline with wave-cut benches and sea stacks is shaped mainly by uplift and waves, whereas Acadia’s rugged coastline also reflects this Pleistocene process that carved U-shaped valleys and polished granite domes
What is glaciation?
Small crustal blocks and oceanic sediments can be welded onto a continent at subduction zones through this process, which helped build parts of coastal Alaska and northern California
What is tectonic accretion?
These are fractures in rock with no measurable movement along them; they helped control landforms like those in Arches and Bryce Canyon
What are joints?
In Joshua Tree National Park, rounded granite “island rocks” formed mainly by spheroidal weathering and exfoliation during past, wetter climates are called these
What are inselbergs?
In Hot Springs National Park, groundwater circulates for thousands of years, is heated at depth, then rises quickly along faults. Unlike Yellowstone, the water carries few dissolved minerals, so it does not build thick deposits of this material
What are extensive mineral/travertine deposits?
Great Smoky Mountains and Shenandoah record multiple Paleozoic orogenies with complex thrust faulting that stack older rocks over younger ones. This contrasts with Great Basin and Death Valley, which formed mainly during this later tectonic regime in the Cenozoic
What is crustal extension and block faulting in the Basin and Range Province?