Sediment Supply Flashcards
What are the four types of sediments?
Clastic Sediments: mineral and rock fragments resulting from rock partitioning by mechanical or chemical processes (are the most abundant)
Biogenous Sediments: shells/skeletons of any organism (2nd most abundant)
Chemical/Authigenic Sediments: Minerals precipitated in sea water
What are the three overarching parameters that control sediment distribution?
Lithogenic processes: Comes from rocks therefore, Proximity to Source, Means of Transport, Distribution Environment, Quantity, Processes of dissolution, Precipitation Process
Biogenic processes: Productivity, Dissolution Processes, Precipitation Processes
Hydrogenous/Authigenic processes: chemical processes, therefore Dissolution Processes, Precipitation Processes
What are the sedimentary sources?
Aeolian Transport: from wind
Coastal Erosion: erosion of coastal areas
Fluvial Transport: River inputs
Groundwater Transport: influx of freshwater with sediments from coastal groundwaters
Icebergs: Sediments trapped in ice or dragged by ice (creates Moraines and Heinrich Layers)
Authigenic Chemical Processes: precipitation of chemical elements in water
Organic Production: dead biota (Oozes)
What are evaporites?
Water-soluble sedimentary mineral deposit that results from concentration & crystallization by evaporation from aqueous solution
A type of Authigenic sediment
Occurs when evaporation>water influx
What is an Ooze?
Any marine sediment made of >30% biogenic (shells/skeletons)
Most commonly:
i. siliceous ooze: Radiolaria and diatoms
ii. Calcareous ooze: Foraminifera, coccolithophore, pteropods
What is the main sedimentary source to ocean basins?
Fluvial transport/River inputs
What is a Moraine?
Sediment deposit “lines” left by a receding glacier
What is a Heinrich Layer?
Sediments deposited by a melting iceberg. The sediment composition is easily distinguishable from the typical biogenic sediments. Therefore, identifying Heinrich layers in sediment cores is how we track glaciations and deglaciation
