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Age-estimate evidence for a complex Middle to Late Pleistocene fluvial terrace aggradation spanning more than a 100-kyr interglacial–glacial cycle at Sutton Cross, eastern England
Proceedings of the Geologists' Association ( IF 1.2 ) Pub Date : 2020-11-22 , DOI: 10.1016/j.pgeola.2020.09.001
H.E. Langford , H. Griffiths , D.J. Horne , D.H. Keen , K.E.H. Penkman

At Sutton Cross, eastern England, an undated River Nene 2nd Terrace was known to record a complex sequence of late Middle to Upper Pleistocene deposits. Amino acid geochronology was carried out for samples from four separate facies associations in order to provide a chronostratigraphic framework for this complex deposit. Each sample comprised three specimens of Bithynia tentaculata opercula. The intracrystalline protein decomposition results confirmed the sedimentary stratigraphic interpretation previously proposed for the site, i.e., that fossiliferous sediments yielding fully temperate Mollusca and Ostracoda faunas are equivalent in age to marine isotope stage (MIS) 7. Palaeotemperature reconstructions based on the Ostracoda fauna (July: +14 to +26 °C; January: ―4 to +5/+3 °C) embrace those of today at this location (July: +17 °C; January +3 °C). The sedimentary succession at Sutton Cross comprises vertically aggraded packages with a probable maximum age of MIS 8 and minimum age of MIS 2. This aggradation pattern (and age range) is also common to downstream sedimentary successions at Whittlesey, and is counterintuitive to the traditional terrace stratigraphy approach that expects laterally aggrading downstepping packages. The preservation of sediments of MIS 7 age and older at Sutton Cross with no evidence of glacial overriding places constraints on recently proposed late Middle Pleistocene regional ice limits.



中文翻译:

在英格兰东部萨顿克罗斯,经历了一个超过100年的冰期-冰期循环,年龄复杂的中更新世晚期河床阶地集聚的年龄估算证据

在英格兰东部的萨顿克罗斯(Sutton Cross),一个未注明日期的内内河第二阶地(River Nene 2nd Terrace)记录下中晚期至上更新世沉积的复杂序列。对来自四个不同相协会的样品进行了氨基酸地质年代学研究,以便为这种复杂的矿床提供年代地层学框架。每个样品包含三个Bithynia tentaculata opercula标本。晶体内蛋白质的分解结果证实了先前对该地点提出的沉积地层解释,,认为产生完全温带Mollusca和Ostracoda动物区系的化石沉积物的年龄与海洋同位素阶段(MIS)7相同。基于Ostracoda动物区系的古温度重建(7月:+14至+26°C; 1月:“-4至+5” / + 3°C)包含今天的温度(7月:+17°C; 1月+3°C)。萨顿克罗斯(Sutton Cross)的沉积演替包括垂直凝结的包裹,可能的最大年龄为MIS 8,最小为MIS2。这种凝结模式(和年龄范围)在惠特尔西的下游沉积演替中也很常见,这与传统阶地有悖常理。地层学方法,期望横向升级降级软件包。

更新日期:2020-12-16
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