Holocene environment of Central Kamchatka, Russia: Implications from a multi-proxy record of Two-Yurts Lake
Holocene environment of Central Kamchatka, Russia: Implications from a multi-proxy record of Two-Yurts Lake
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DOI：
10.1016/j.gloplacha.2015.07.011
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发表时间：
2015-11
影响因子：
3.9
通讯作者：
Ulrike Hoff;B. Biskaborn;V. Dirksen;O. Dirksen;G. Kuhn;H. Meyer;L. Nazarova;A. Roth;B. Diekmann
中科院分区：
文献类型：
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作者：
Ulrike Hoff;B. Biskaborn;V. Dirksen;O. Dirksen;G. Kuhn;H. Meyer;L. Nazarova;A. Roth;B. Diekmann
在俄德古环境研究的范围内，两个Yurts湖(Tyl，俄语中的Dveh-Yurtochnoe)被选为破译堪察加全新世气候变异性的主要科学靶区。这个5米×2公里大、26米深的湖泊起源于冰川，位于堪察加中部山谷西北端Sredinny Ridge的东侧，不受活火山活动的直接影响。在这里，我们展示了一项关于沉积物岩心的多代理研究结果，该研究跨越了大约过去7000年。TYL记录的总基调是从花粉和硅藻数据以及有机碳的同位素组成推断，在公元5000-4500年之后，大陆性和冬季积雪增加，同时温度、湿度和生物生产力下降。Tyl Proxy的数据还表明，全新世晚期被两个较冷的时期打断，大约在距今4500至3500千卡年和距今1000至200千年之间，分别是新冰川时代和小冰河时代的局部表达。这些环境变化可被视为对气候变化的直接和间接反应，区域陆地和海洋领域的其他记录也证明了这一点。长期气候恶化是由日照减少推动的，而短期气候漂移最好的解释是当地的气候过程。后者影响控制气源的大气压力系统的结构，以及到达堪察加的气团的温度和湿度。
Within the scope of Russian–German palaeoenvironmental research, Two-Yurts Lake (TYL, Dvuh-Yurtochnoe in Russian) was chosen as the main scientific target area to decipher Holocene climate variability on Kamchatka. The 5 × 2 km large and 26 m deep lake is of proglacial origin and situated on the eastern flank of Sredinny Ridge at the northwestern end of the Central Kamchatka Valley, outside the direct influence of active volcanism. Here, we present results of a multi-proxy study on sediment cores, spanning about the last 7000 years. The general tenor of the TYL record is an increase in continentality and winter snow cover in conjunction with a decrease in temperature, humidity, and biological productivity after 5000–4500 cal yrs BP, inferred from pollen and diatom data and the isotopic composition of organic carbon. The TYL proxy data also show that the late Holocene was punctuated by two colder spells, roughly between 4500 and 3500 cal yrs BP and between 1000 and 200 cal yrs BP, as local expressions of the Neoglacial and Little Ice Age, respectively. These environmental changes can be regarded as direct and indirect responses to climate change, as also demonstrated by other records in the regional terrestrial and marine realm. Long-term climate deterioration was driven by decreasing insolation, while the short-term climate excursions are best explained by local climatic processes. The latter affect the configuration of atmospheric pressure systems that control the sources as well as the temperature and moisture of air masses reaching Kamchatka.