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首页> 外文期刊>Journal of Paleolimnology >Holocene paleostorms identified by particle size signatures in lake sediments from the northeastern United States
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Holocene paleostorms identified by particle size signatures in lake sediments from the northeastern United States

机译：通过粒度特征识别的全新世古风暴来自美国东北部的湖泊沉积物中

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The frequency and timing of Holocene paleofloods in the hilly terrain of New Hampshire and Maine are identified using 14C and high-resolution (cm-by-cm) particle size analysis of sediment cores taken from six post-glacial lakes (~0.1–1.4 km2). A total of nine sediment cores (4.5–6 m long) were taken near the base of stream delta foreslopes. End-member modeling of the particle-size frequency distributions from each core produces 3–5 representative end member distributions, or end members (EMs). Concurrent increases in mean and median particle size, and in the relative abundance of the coarsest EM(s), indicate increased transport capacity of inflowing tributaries, resulting from rainstorms. In all 9 cores, particle size data show clear signs of episodic, high-energy sediment transport events where proxy measurements such as loss-on-ignition and magnetic susceptibility do not, demonstrating the sensitivity of particle size analysis in paleostorm investigations made using lake sediment cores. Floods caused by storms in this region peaked around 1.4, 2.1, 3.0, 3.9, 6.8, 8.2, and 11.5 ka cal BP, and presently appear to be increasing in frequency. Periods of storminess in New Hampshire and Maine correlate well with other records of precipitation and climate in the northeastern United States during the Holocene, further supporting modern records which show tropical air masses as a primary driver of extreme precipitation events in New England (Ludlum 1996; Konrad 2001; Sisson and Gyakum 2004). Keywords Paleoflood - Grain size - Climate - Lake sediment - New England
机译：使用 14 C和高分辨率（cm-cm）的粒度分析，从新罕布什尔州和缅因州的丘陵地带中全新世古洪水的频率和时间确定，该分析取自六个后冰川湖（〜0.1–1.4 km 2 ）。在河三角洲前斜坡的底部附近总共采集了9个沉积物岩心（4.5–6 m长）。每个核的颗粒尺寸频率分布的末端成员建模产生3–5个代表性的末端成员分布或末端成员（EM）。平均和中值粒径的同时增加，以及最粗糙的EM的相对丰度，表明暴雨导致流入支流的运输能力增加。在所有9个岩心中，粒度数据均显示出明显的偶发性高能沉积物传输事件的迹象，而点火损耗和磁化率等替代测量却没有，这表明使用湖泊沉积物进行的古风暴研究中粒度分析的敏感性核心。该地区由风暴引起的洪水在1.4、2.1、3.0、3.9、6.8、8.2和11.5 ka cal BP附近达到峰值，目前看来频率在增加。新罕布什尔州和缅因州的暴风雨时期与全新世期间美国东北部的其他降水和气候记录有很好的相关性，进一步支持了现代记录，这些记录表明热带气团是新英格兰极端降水事件的主要驱动力（Ludlum 1996； 1996）。 Konrad 2001； Sisson and Gyakum 2004）。关键词泛洪-粒度-气候-湖泊沉积物-新英格兰

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