Assessing the impact of historical metal mining on upland landscapes : a nested sediment budget approach
Assessing the impact of historical metal mining on upland landscapes : a nested sediment budget approach
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评估历史金属开采对高地景观的影响：嵌套沉积物预算方法
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发表时间：
2016
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通讯作者：
M. Kincey
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作者：
M. Kincey
历史上的金属开采造成了广泛的景观干扰，并将大量受污染的废弃沉积物输送到河流系统中。前采矿景观典型的较高侵蚀率也意味着历史采矿的地貌遗产远远超出了开采活跃期。尽管河道对采矿沉积物负荷的响应经常有详细记录，但相关流域扰动的规模和分布以及与河流系统的耦合却知之甚少，也很少量化。因此，本研究评估了英国北奔宁山脉历史上铅矿开采造成的景观干扰和沉积物产生的变化。重建了 1700 年至 1948 年期间历史沉积物生产的分布区域趋势和地貌意义。使用地貌变化检测的嵌套尺度和沉积物预算方法，对 Whitesike 和 Bentyfield 矿的废弃后侵蚀（1868-2014）进行了详细量化。
结果表明，研究区历史采矿产生了约 7.2 吨废弃沉积物，但只有约 2.3 吨废物仍然储存在沉积地貌中；导致净沉积物产量 >4.8 公吨。来自压榨的废弃沉积物产量（~4.6 公吨）显着高于地下采矿的废弃物沉积物产出（~2.6 公吨）。历史采矿的时空模式也相当复杂。与南泰恩区 (~20000 t km-2)、Upper Tees (~19000 t km-2) 和 Black Burn (~4000 t km-2) 相比，Nent 地区矿井沉积物产生强度最高 (~79000 t km-2)。模拟的沉积物连通性在 Nent 河中也最高，使其成为扰动水平最显着且坡度河道耦合最有效的流域。
对 Whitesike 和 Bentyfield 废弃后变化的分析表明，河流过程是历史矿山侵蚀的主要驱动因素，包括冲沟 (187 t a-1) 和河岸侵蚀 (93 t a-1)。还记录了侵蚀率明显的时间变化，主要沟壑系统总净变化的 76% 发生在一个月的时间间隔内（2013 年 5 月），并与高强度风暴相关。废弃矿山的大规模变化是由高强度、低频降雨事件驱动的，尽管频繁的低强度变化在确定总沉积物产量方面发挥着重要的准备作用。这项研究强调了密集开采的高地景观中地貌学和考古学之间复杂的相互作用，以及对它们的理解和管理采用跨学科方法的必要性。
Historical metal mining has caused extensive landscape disturbance and the delivery of vast quantities of contaminated waste sediments to fluvial systems. The higher erosion rates typical of former mining landscapes also means that the geomorphological legacy of historical mining extends well beyond the active period of extraction. Although channel responses to sediment loading from mining are often well-documented, the scale and distribution of associated catchment disturbance and coupling with the fluvial system are poorly understood and rarely quantified. This study therefore assesses variability in landscape disturbance and sediment production resulting from historical lead mining in the North Pennines, UK. Regional trends in the distribution and geomorphic significance of historical sediment production were reconstructed for the period 1700-1948. Post-abandonment erosion (1868-2014) was quantified in detail at Whitesike and Bentyfield mines, using nested scales of geomorphic change detection and a sediment budget approach.
The results show that ~7.2 Mt of waste sediment were produced by historical mining in the study area but only ~2.3 Mt of this waste is still stored in depositional landforms; resulting in a net sediment output of >4.8 Mt. Waste sediment output from hushing (~4.6 Mt) was significantly higher than that from subterranean mining (~2.6 Mt). Considerable complexity in spatial and temporal patterns of historical mining was also recorded. The intensity of mine sediment production was highest within the Nent (~79000 t km-2), compared with the South Tyne (~20000 t km-2), Upper Tees (~19000 t km-2) and Black Burn (~4000 t km-2). Modelled sediment connectivity was also highest for the Nent, making this the catchment with the most significant level of disturbance and the most efficient slope-channel coupling.
Analysis of post-abandonment change at Whitesike and Bentyfield indicates that fluvial processes are the key drivers of erosion at historical mines, including gullying (187 t a-1) and bank erosion (93 t a-1). Pronounced temporal variation in erosion rates was also recorded, with 76% of the total net change to the main gully system occurring within one monthly interval (May 2013) and associated with a high intensity storm. Large-scale changes at abandoned mines are driven by high magnitude, low frequency rainfall events, although frequent low magnitude changes play an important preparatory role in determining overall sediment yields. This research emphasises the complex interactions between geomorphology and archaeology within intensively mined upland landscapes and the need for interdisciplinary approaches to their understanding and management.