Lecture 6 09 12 2014 Sediment Cycle Transport Transporting sediments happens mainly in rivers headwaters floodplains delta Each part of the river have different sediments found there Headwaters the heavy fast moving waters can move the heavy rocks Boulders Gravel Floodplain cant find boulders and gravel because the water is moving too slowly to carry them Sand Mud Delta Sand Mud Flooding Most transport happens during floods Rain covers part of floodplain 10 yrs Lots of rain covers all of floodplain 100 yrs 09 12 2014 Glaciers and Wind Transport Glaciers needs to be cold to have a glacier have a black line running down center which is dirt and mud Very good at grinding up carving rocks on the inside at bottom at top of the ice Breaks the rocks down into small pieces Glaciers are basically slow moving rivers made of ice Snow falls at the top and weighs down gravity pulls down glacier structure from high elevation to the low elevation Some glaciers sediments make it to the ocean o But most deposit sediment on land where it can be carried by rivers if river is strong enough In cold places high elevation latitude glaciers are great mean of transport Sediments carried by the wind Mostly desert sand and dust mostly dust Haboobs dust storm can be a mile tall Sahara desert biggest desert on earth wind blows east west Transporting sediment there are 3 ways River o If you re in a place where there are rivers Wind o If you re in a desert Glaciers o If you re in a place that is cold with a lot of snow 09 12 2014 Sediment Cycle Deposition Sediment on continental shelf Sand Mud Skeletons First thing you get on beach is sand As you get further out in beach you get more skeletons hard parts of living organisms animals or plants Marine life Calcite Limestone o Calcite is a mineral that becomes limestone Skeletons Calcite Limestone o Sedimentary Layers like grand canyon the mountains are a ton of sediments laid down on top of each other in layers over hundreds of years Skeletons calcite Mud Sand 09 12 2014 Sediment Cycle Deposition Sediment on the deep ocean floor Sediments in the deep water 1 2 3 Turbidite submarine landslide sand mud skeletons sediment built up on continental shelf but moved around by wind driven waves and eventually find way into submarine canyon and tumble off into giant submarine landslide made up of everything found on a shelf thickest sediments found just over the edge of a shelf Sand and Dust blown in from deserts covers much of the deep sea floor mud Skeletons of marine organisms These organisms including plants live get eaten get pooped out sometimes just live and die and then sink to ocean floor What kind of sediments do you find on the ocean floor Diatoms most abundant organism on earth in terms of mass o A type of plankton microscopic and floating cant control where it is going flows with the currents o skeletons are made of quartz silicone dioxide o phytoplankton lets sunlight in photosynthesis o live and die cover huge part of ocean floor Coccoliths 2nd most abundant organism in terms of mass o Type of phytoplankton they photosynthesis o Make hard parts of calcite calcium carbonate o Dominate some parts of ocean floor that diatoms do not 09 12 2014 Sediment Cycle Recap Reasons why there is thin sediment over a mid ocean ridge Spreading centers Far from land Physical changes