04-TectandSedSup - T e c to n ic E f f e c ts o n S e d im...

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Unformatted text preview: T e c to n ic E f f e c ts o n S e d im e n t S u p p ly & D is tr ib u tio n • Riverine discharge • Barrier distribution • Shelf Width * Wave energy * Sediment dispersion * Prox. of submarine canyons • Failed third arm and river location • Cliff coast processes and morphology R iv e r in e S e d im e n t D is c h a r g e • Tectonic setting • Drainage area & divides • Precipitation & evaporation • Ruggedness of terrain • Glaciated D r a in a g e D iv id es Topographically higher areas Rivers East of Andes: Large Ad Rivers flow toward Pacific: Small Ad Ad - Drainage Area Area Drained by a River Andes Mountains form Drainage Divide When it rains over South America where does all the water drain? In d us G a n g es B r a h m a p u tr a Copper River Delta Barriers Chugach Mountains Copper River Gulf of Alaska Magdalena Drainage System Magdalena R. Factors Small Ad R u g g e d te r r a i n H i g h p r e c i p i ta ti o n H ig h S ed im en t d is ch a r g e Drainage Basin shown in yellow and green S ed im en t D isch a r g es Sediment Discharge (vol./time) Qs Magdalena Sediment Discharge vs. Drainage Area Magdalena - 250 x 106 tons/yr, Ad = 23,000 km2 Amazon - 2000 x 106 tons/yr, Ad = 6,100,000 km2 Niger - 20 x 106 tons/yr, Ad = 2,300,000 km2 Amazon Niger Climatic Effects Precipitation Evaporation Drainage to World’s Oceans W o r ld ’ s la n d s u r fa ce d r a in ed A tl a n ti c 4 3% A r c ti c 1 4% P a cific 1 2% I n d ia n 1 2% A n ta r c ti c 9% M e d i te r r a n e a n 0 .5 % G u lf o f M ex ico 0 .4 % Ocean Relationship of Major Rivers and Tectonic Coastal Classification High Sediment Discharge Rivers include: A d ( x 1 06 ) Q (x 106 ) (Big Circles on diagram) s M is s is s ip p i A m azon In d us Y a n g tz e Irra w a d d y G a n g e s -B r a h m a p u tr a M ek o n g T i g r e s s -E u p h r a te s Y e l l o w (H u a n g -H e ) M a g d a len a 3 .2 6 .1 1 .1 1 .7 0 .4 1 .6 0 .8 1 .4 0 .9 0 .0 2 0 .5 1 .0 0 .5 0 .2 5 0 .2 5 2 .0 1 .0 0 .2 5 0 .5 0 .2 5 Ganges-Brahmaputra Delta Sediment Discharge of Major Rivers Freshwater discharge versus Sediment discharge Northern Rivers Qw Southern Rivers Qs Continental Shelves Formed by Sediment Deposition They affect waves and tides Proximity of Submarine Canyons Coastal Plain provides sediment supply and even platform for barrier development Submarine Canyons Similar to Canyons on Land (Grand Canyon) Canyons cut into continental slope and extend onto continental shelf Canyons formed by Water and Sediment moving down slope due to Gravity Occur throughout continental margins of the world Salt River Canyon, USVI Sand cascading into submarine canyon Los Angeles Los W e st C o a st - C o llisio n C o a st Narrow Continental Shelf Submarine Canyons close to shore Siphon sand to deep ocean floor Shelf Width Controls Wave Energy Narrow Shelf-Little Attenuation of wave energy-Big Waves Wide Shelf-High Attenuation of wave energy-Small Waves Narrow Continental Shelf Huge Waves Cape Point River Drainage - Failed Third Arms • Related to rift valleys • Formed during break up of Pangea • Become sites of internal continental drainage • Coincide with major rivers Failed Third Arm (relationship to Continental Drainage) Location of major rivers Rising Plume of Magma domes overlying Lithosphere stretching and thinning it When rupture occurs it causes a Three-Arm Tear Failed Third Arms D o m in g R i f ti n g L in ea r S ea Southern Panagea Gondwanaland Failed Third Arms Sacramento River Collision coast have small low sediment discharge rivers San Joaquin River Contrasting Coasts East Coast P l a te P o s i ti o n V o lc a n ism E a r th q u a k e s C o n ti n e n ta l S h e l f W i d th A d ja cen t M a in la n d D e p o s i ti o n a l F e a tu r e s C o a s ta l T r i p A m e r o -T r a ilin g -E d g e No M in o r W id e F l a t C o a s ta l P l a i n B a r r i e r s C o n ti n u o u s B o r in g West Coast C o llis io n C o a s t A c ti v e V o l c a n i s m M a jo r N arrow M o u n ta i n s > 3 0 0 0 m P o ck et B ea ch es , M in o r S p i ts S p e c ta c u l a r ...
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