Lakesdating

Energy Link’s first electricity price forecast was published in 1997 and since then we have literally produced hundreds of up-to-the-minute forecasts of prices in both the electricity and gas markets.The forecasts are produced using complex market models, but we rely on our insight to formulate the key inputs to the models, which ultimately drive the evolution of market behaviour and prices.During winter months, when meltwater and associated suspended sediment input is reduced, and often when the lake surface freezes, fine clay-size sediment is deposited forming a dark coloured laminaset.In addition to seasonal variation of sedimentary processes and deposition, varve formation requires the absence of bioturbation.Indeed, clay flocculation occurs at high ionic strength due to the collapse of the clay electrical double layer (EDL), which decreases the electrostatic repulsion between negatively charged clay particles.

This prompted him to suggest the coarse-fine couplets frequently found in the sediments of glacial lakes were annual layers.The classic varve archetype is a light / dark coloured couplet deposited in a glacial lake.The light layer usually comprises a coarser laminaset, a group of conformable laminae, consisting of silt and fine sand deposited under higher energy conditions when meltwater introduces sediment load into the lake water.The word 'varve' derives from the Swedish word varv whose meanings and connotations include 'revolution', 'in layers', and 'circle'.The term first appeared as Hvarfig lera (varved clay) on the first map produced by the Geological Survey of Sweden in 1862.However, by 2012, “missing” varves in the Lake Suigetsu sequence were identified in the Lake Suigetsu 2006 Project by overlapping multiple cores and improved varve counting techniques, extending the timescale to 52,800 years.Varves form in a variety of marine and lacustrine depositional environments from seasonal variation in clastic, biological, and chemical sedimentary processes.Initially, "varve" referred the separate components of annual layers in glacial lake sediments, but at the 1910 Geological Congress, the Swedish geologist Gerard De Geer (1858–1943) proposed a new formal definition, where varve means the whole of any annual sedimentary layer.More recently introduced terms such as 'annually laminated' are synonymous with varve.De Geer and his co-workers and students made trips to other countries and continents to investigate varved sediments. By this stage, other geologists were investigating varve sequences, including Matti Sauramo who constructed a varve chronology of the last deglaciation in Finland.1940 saw the publication of a now classic scientific paper by De Geer, the Geochronologia Suecica, in which he presented the Swedish Time Scale, a floating varve chronology for ice recession from Skåne to Indalsälven.

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  1. Oct 23, 2017. and climate change on the world's saline lakes, dating as far back as 1300 years ago when the huge lakes of China's Tarim Basin were dried.

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