The role of fire in landscape dynamics: An example of two sediment records from the Rodna Mountains, northern Romanian Carpathians
The role of fire in landscape dynamics: An example of two sediment records from the Rodna Mountains, northern Romanian Carpathians
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DOI：
10.1016/j.catena.2015.10.021
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发表时间：
2016-02
期刊：
影响因子：
6.2
通讯作者：
A. Haliuc;S. Hutchinson;G. Florescu;A. Feurdean
中科院分区：
文献类型：
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作者：
A. Haliuc;S. Hutchinson;G. Florescu;A. Feurdean
火是世界范围内一种重要的干扰因子，也是引起地貌变化的主要原因之一。根据其特点（规模、持续时间、温度），火灾引起土壤稳定性的变化，改变渗透，促进土壤侵蚀。在这里，我们采用了一套物理（矿物磁性，烧失量），地球化学（X射线荧光衍生元素数据），生物（宏观木炭，花粉）代理和测年测量（AMS 14 C，210 Pb和137 Cs），以研究火灾活动，沉积特征和地貌变化之间的关系在全新世。我们的研究结果强调，火灾事件的印记，其特征在于二次亚铁磁组合，特别是非常精细的超顺磁性（SP）磁铁矿和磁赤铁矿的磁性签名。在湖Buhiescu马雷，全新世早期的特点是中度火灾活动和较粗的沉积物颗粒大小表明一个相对不稳定的集水区燃烧事件激活侵蚀过程的影响。随后，晚全新世（4000 -0 cal yr. BP）的特点是间歇性变化的火灾活动与零星增加之间的3,400和3,200卡年。BP和大约2,000 cal yr。BP燃烧时是强大的，足以导致磁性富集的表土和碎屑输入到湖泊。在我们的高分辨率记录中，Lake Aristiol，间隔为2，500 -700 cal/年。BP以及过去100年的特点是强烈的燃烧，与持续的地表土壤侵蚀和磁性富集相一致。火----侵蚀----景观的关系随着时间的推移而变化，在很大程度上取决于火的行为、火的时空分布和景观特征（坡度、土壤类型、植被覆盖）。
Fire is an important disturbance agent worldwide and one of the major causes of geomorphological change. Dependent on its characteristics (size, duration, temperature), fire induces changes in soil stability, modifying infiltration and promoting soil erosion. Here, we employ a suite of physical (mineral magnetic, loss-on-ignition), geochemical (XRF derived elemental data), biological (macro-charcoal, pollen) proxies and dating measurements (AMS14C,210Pb and137Cs) to examine the relationship between fire activity, sedimentary characteristics and geomorphological change over the Holocene. Our results highlight that fire events imprint a magnetic signature characterised by secondary ferrimagnetic assemblage particularly very fine superparamagnetic (SP) magnetite and maghemite. In Lake Buhăiescu Mare, the early Holocene is characterised by moderate fire activity and coarser sediment particle size indicating a relatively unstable catchment affected by burning events which activated erosional processes. Subsequently, the late Holocene (4,000–0 cal yr. BP) is marked by intermittently variable fire activity with sporadic increases between 3,400 and 3,200 cal yr. BP and around 2,000 cal yr. BP when burning was strong enough to lead to the magnetic enrichment of topsoil and detrital inputs to the lake. In our high resolution record, Lake Știol, the interval 2,500–700 cal yr. BP, and also the last 100 years, are characterised by intense burning that coincides with sustained surface soil erosion and magnetic enrichment. The fire–erosion–landscape relationship varies over time being highly dependent on fire behaviour, fire temporal and spatial distribution and landscape features (slope, soil type, vegetation cover).