Pleistocene age varves at Scarborough Bluffs, Toronto, Ontario, Canada. The thickest varves are more than half an inch thick.
A varve is an annual layer of sediment or sedimentary rock.
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.[1]
Initially, "varve" referred to each of the separate components comprising a single annual layer 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.[2] More recently introduced terms such as 'annually laminated' are synonymous with varve.
Of the many rhythmites in the geological record, varves are one of the most important and illuminating in studies of past climate change. Varves are amongst the smallest-scale events recognised in stratigraphy.
Geological park with varves in Itu, Brazil
An annual layer can be highly visible because the particles washed into the layer in the spring when there is greater flow strength are much coarser than those deposited later in the year. This forms a pair of layers—one coarse and one fine—for each annual cycle. Varves form only in fresh or brackish water, because the high levels of salt in normal sea water coagulate the clay into coarse grains. Since the saline waters leave coarse particles all year, it is nearly impossible to distinguish the individual layers in salt waters. 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.[citation needed]
^Zolitschka, B. (2007). "Varved lake sediments" (PDF). Encyclopedia of Quaternary Science: 3105–3114. Archived from the original (PDF) on 2015-09-22. Retrieved 2014-03-19.
^De Geer, G. (1912). A geochronology of the last 12,000 years. Proceedings of the International Geological Congress Stockholm (1910),1, 241–257.
A varve is an annual layer of sediment or sedimentary rock. The word 'varve' derives from the Swedish word varv whose meanings and connotations include...
thickness of sediment layers (known as "varve analysis"—the term "varve" means a layer or layers of sediment. Typically, varve refers to lake or glacial sediment)...
geomorphology and geochronology. De Geer is best known for his work on varves. In 1890 De Geer was the first to apply the name Ancylus Lake to the Baltic...
technique such as ice core dating, dendrochronology, uranium-thorium dating or varve analysis is used as the primary method for age determination. If age is...
components (such as lamp filaments) and in hardening alloys (such as steel)" varve, "a pair of layers of alternately finer and coarser silt or clay believed...
identified using X-ray diffraction rather than chemical or physical tests. Varve (or varved clay) is clay with visible annual layers that are formed by seasonal...
Prefectural Varve Museum is a geological and archeological museum located in Wakasa, Mikatakaminaka District, Fukui Prefecture, Japan. It features varve ranging...
the types of nutrients available. A paired (black and white) layer of the varved lake sediments correspond to a year. During winter, when organisms die,...
light-hue inorganic layer in the dry season. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present...
only penetrated the first few meters of sediment, they provided sufficient varves to give proxy climate data for up to 14,570 years BP. A team of scientists...
time-transgressive even within there. After an examination of laminated varve sequences, Muschitiello and Wohlfarth found that the environmental changes...
the innermost belong to the LGP. Llanquihue Lake's varves are a node point in southern Chile's varve geochronology. During the last glacial maximum, the...
sediment or sedimentary rock laid down with periodicity and regularity Varve – Annual layer of sediment or sedimentary rock "Science writer Richard Hill...
ISSN 0016-7606. Retrieved 11 September 2023. Bradley, W. H. (1930). "The varves and climate of the Green River epoch". U.S. Geological Survey Professional...
sediments, or varves: silt and sand in the summertime (due to glacial meltwater) and clay in the wintertime (as the lake froze). Analysis of varves along Canoe...
improvements to these curves are based on new data gathered from tree rings, varves, coral, plant macrofossils, speleothems, and foraminifera. There are separate...
out, forming a thin layer on the ocean floor. Each band is similar to a varve, resulting from cyclic variations in oxygen production. Banded iron formations...
of Lake Huron, with giant layers of now-lithified till beds, dropstones, varves, outwash, and scoured basement rocks. Correlative Huronian deposits have...
Laminae that represent seasonal changes (similar to tree rings) are called varves. Any sedimentary rock composed of millimeter or finer scale layers can be...
are the Quaternary deposits. The materials of these deposits are till, varved clay, sand, gravel, and pebbles that are of glacial, marine and lacustrine...
minerals (particularly carbonates), grain size, thickness of sediment layers (varves) and fossil diversity with time, related to seasonal or longer term changes...
deposited all over the lake bed. Glaciolacustrine deposits commonly form varves, which are annually deposited layers of silt and clay, where silt is deposited...
the region between AD 26 and 36. This earthquake was dated by counting varves (annual layers of sediment) between the disruptions in a core of sediment...
Mekhaldi, Florian; Adolphi, Florian (31 May 2018). "Synchronizing 10Be in two varved lake sediment records to IntCal13 14C during three grand solar minima"....
in 1999. The Russian scientists in 2017 counted at least 280 such annual varves in the 1260 mm long core sample pulled from the bottom of the lake, representing...
found in the geological record, varves are among the most important and illuminating to studies of past climate change. Varves are amongst the finest resolution...
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