In [[sedimentary geology]], '''maturity''' describes the composition and texture of grains in [[clastic rock]]s, most typically [[sandstone]]s, resulting from different amounts of [[Sediment transport|sediment transportation]]. A sediment is mature when the grains in a sediment become [[Sorting (sediment)|well-sorted]] and [[Rounding (sediment)|well-rounded]] due to [[weathering]] or abrasion of the grains during transport. There are two components to describe maturity, ''texture'' and ''composition''. [[Texture (geology)|Texture]] describes how rounded and sorted the sample is while composition describes how much the composition trends toward stable [[mineral]]s and components (often [[quartz]]).
A mature sediment is more uniform in appearance, for the sediment grains are well rounded, are of a similar size and exhibit little compositional variation. Conversely, an immature sediment contains more angular grains, diverse grain sizes, and is compositionally diverse.<ref name=Boggs2006>{{cite book | author = Boggs Jr., S. | year = 2006 | title = Sedimentology and Stratigraphy | publisher = Pearson Education | isbn = 0-13-154728-3 | url = }}</ref>
As the sediment is transported, the unstable minerals are abraded or dissolved to leave more stable minerals, such as [[quartz]]. Mature sediments, which contain stable minerals, generally have a smaller variety of minerals than immature sediments, which can contain both stable and unstable minerals. One measure of this maturity is the [[ZTR index]] which is a measure of the common resistant minerals found in ultra-weathered sediments: [[zircon]], [[tourmaline]], and [[rutile]].
A sediment sample from the lower (downstream) portions of a stream is likely to be more mature than one found upstream, since the original sediment has been subject to more abrasion as it travels downstream.
==See also== *[[Maturity (geology)]]
==References== {{reflist}}
[[Category:Sedimentology]]
https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/38/4/1326/96178 [[Basu, A. (1985). Reading provenance from detrital quartz. In Provenance of arenites (pp. 231-247). Springer, Dordrecht.]]
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