Lateglacial and Holocene environmental history of the central Kola region, northwestern Russia revealed by a sediment succession from Lake Imandra
Lateglacial and Holocene environmental history of the central Kola region, northwestern Russia revealed by a sediment succession from Lake Imandra
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DOI：
10.1111/bor.12465
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发表时间：
2020-09
期刊：
影响因子：
2.2
通讯作者：
M. Lenz;L. Savelieva;L. Frolova;A. Cherezova;M. Moros;Marlene M. Baumer;R. Gromig;N. Kostromina;N. Nigmatullin;V. Kolka;B. Wagner;G. Fedorov;M. Melles
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文献类型：
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作者：
M. Lenz;L. Savelieva;L. Frolova;A. Cherezova;M. Moros;Marlene M. Baumer;R. Gromig;N. Kostromina;N. Nigmatullin;V. Kolka;B. Wagner;G. Fedorov;M. Melles
Bolshaya Imandra是伊曼德拉湖的北部次盆地，通过水声测量对其进行了调查，然后对沉积物进行了取样，直至声学基底。采用物理、生物地球化学、沉积学、颗粒学和微体古生物学相结合的方法对沉积物记录进行分析，重建区域气候和环境历史。通过14C测年、137c测年、Hg测年以及花粉地层学分析，对该湖泊进行了年代学控制，揭示了该湖泊的沉积演替首次提供了跨越冰川期和全新世的连续记录。在约13200 cal. a BP之前的冰川消退之后，湖泊的次盆地最初被一个冰川河流系统所占据，然后建立了一个具有冰川湖沉积的前冰湖。相对温和的气候、稀疏的植被覆盖和斯堪的纳维亚冰盖（SIS）从湖泊集水区连续退缩是Bølling/ allerd间冰期的特征，持续到12710 cal. a BP。在随后的新仙女木时期，直到11 550 cal. a BP，气候变冷导致植被覆盖减少和SIS的重新推进。在全新世过渡时期，SIS冰川从流域消失，但东部湖岸山区的小冰川仍然存在。在全新世早期，直到8400 cal. a BP，沉积由冰湖沉积转变为湖泊沉积，气温上升导致了喜热植被的扩展。中全新世至3700 cal. a BP为区域全新世热最大值（8000-4600 cal. a BP），温度相对稳定，植被覆盖较密集，没有山地冰川。在晚全新世，直到30cal . a BP，山地冰川的再次出现可能是由于轻微的冷却和湿度的增加。自公元前30 cala BP以来，伊曼德拉湖受到人类活动的强烈影响，起源于工业和采矿活动。我们的结果与科拉地区的植被和气候重建结果基本一致。
Bolshaya Imandra, the northern sub‐basin of Lake Imandra, was investigated by a hydro‐acoustic survey followed by sediment coring down to the acoustic basement. The sediment record was analysed by a combined physical, biogeochemical, sedimentological, granulometrical and micropalaeontological approach to reconstruct the regional climatic and environmental history. Chronological control was obtained by 14C dating, 137Cs, and Hg markers as well as pollen stratigraphy and revealed that the sediment succession offers the first continuous record spanning the Lateglacial and Holocene for this lake. Following the deglaciation prior to c. 13 200 cal. a BP, the lake's sub‐basin initially was occupied by a glacifluvial river system, before a proglacial lake with glaciolacustrine sedimentation established. Rather mild climate, a sparse vegetation cover and successive retreat of the Scandinavian Ice Sheet (SIS) from the lake catchment characterized the Bølling/Allerød interstadial, lasting until 12 710 cal. a BP. During the subsequent Younger Dryas chronozone, until 11 550 cal. a BP, climate cooling led to a decrease in vegetation cover and a re‐advance of the SIS. The SIS disappeared from the catchment at the Holocene transition, but small glaciers persisted in the mountains at the eastern lake shore. During the Early Holocene, until 8400 cal. a BP, sedimentation changed from glaciolacustrine to lacustrine and rising temperatures caused the spread of thermophilous vegetation. The Middle Holocene, until 3700 cal. a BP, comprises the regional Holocene Thermal Maximum (8000–4600 cal. a BP) with relatively stable temperatures, denser vegetation cover and absence of mountain glaciers. Reoccurrence of mountain glaciers during the Late Holocene, until 30 cal. a BP, presumably results from a slight cooling and increased humidity. Since c. 30 cal. a BP Lake Imandra has been strongly influenced by human impact, originating in industrial and mining activities. Our results are in overall agreement with vegetation and climate reconstructions in the Kola region.