Fluvial and colluvial deposits of Late Holocene age in South-Central Ontario catchments have provided few 14C dates, most by conventional methods registering century-old ages. Other young deposits, dated by conventional and accelerator mass spectrometry radiocarbon (AMS 14C), have yielded bomb-affected post-1950 ages over variable time limits. Attempts to date the base of Ah and lower-in-section soil horizons, in Early to Late Holocene stream terrace deposits, have yielded atomic bomb effects. Comparing bomb contamination in Late Holocene fluvial deposits, using both conventional and AMS methods, identifies a mix of bomb-affected beds juxtaposed with dated beds, the latter yielding ages with narrow standard deviations. Colluvial deposits overlying key glacial sections in the Rouge Catchment, while rare, yield bracketed AMS ages for an Ahbk horizon that refines weathering times relative to previously obtained conventional 14C dates. Bomb-affected sediment appears variably distributed within floodplain soils and in the ground soil of a colluvial section. Mass wasted deposits, with AMS 14C ages spread over the last few centuries, appear related to Little Ice Age (LIA) changes in climate, corroborated by pollen records. Further, these AMS-14C dated beds calibrate weathering of secondary Fe-Al oxihydroxides over the first half a millennium of weathering time.

中文翻译：

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加拿大安大略省中南部流域河流和崩积层沉积物的放射性碳测量摘要

安大略省中南部流域的全新世晚期的河流和崩积物沉积物提供了很少的14C 日期，大多数是通过传统方法记录百年历史。其他年轻沉积物，通过常规和加速器质谱放射性碳（AMS14C)，在不同的时间限制内产生了 1950 年后受炸弹影响的年龄。在全新世早至晚的溪流阶地沉积物中，对 Ah 底部和下部土壤层进行测定的尝试已产生了原子弹效应。使用传统方法和 AMS 方法比较全新世晚期河流沉积物中的炸弹污染，识别出受炸弹影响的河床与过时的河床并列的混合体，后者产生的年龄具有较小的标准偏差。红河流域主要冰川部分上的崩积物沉积物，虽然罕见，但 Ahbk 地平线的产量范围内的 AMS 年龄相对于之前获得的传统方法改进了风化时间14C 日期。受炸弹影响的沉积物似乎在洪泛区土壤和崩积区的地面土壤中分布不一。大量浪费存款，AMS14C时代在过去几个世纪中传播，似乎与小冰河时代（LIA）的气候变化有关，并得到花粉记录的证实。此外，这些 AMS-14C测年床校准了次生铁铝羟基氧化物在前半个千年的风化时间内的风化。