Quaternary
Quaternary
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DOI：
10.4135/9781446247501.n3167
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Petra Zahajská;P. Frings;Françoise Gaspard;Sophie Opfergelt;Johanna Stadmark;Sherilyn C. Fritz;Rosine Cartier;Daniel J. Conley
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文献类型：
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作者：
Petra Zahajská;P. Frings;Françoise Gaspard;Sophie Opfergelt;Johanna Stadmark;Sherilyn C. Fritz;Rosine Cartier;Daniel J. Conley
考虑到相互竞争的来源和过程控制可以解除卷积，同位素地球化学有可能提供这些重建。黄石国家公园富含二氧化硅的火山和热液系统是进入黄石湖的大量溶解硅的来源，黄石湖是一个高硅系统，因此碳、出口率和富含硅藻的沉积物的形成。黄石湖沉积物应该是过去硅生物地球化学的档案，尽管湖下热液活动或热液爆炸事件的ff等尚不清楚。在这里，我们分析了湖水、支流和黄石湖热液喷口的flUID的溶解硅浓度、同位素组成(𝛿30 Si)和Ge/Si比值，以评估湖泊硅循环中的变异性来源。分析了两个沉积岩芯中的整体元素组成和生物成因的二氧化硅(BSiO2)含量，以及来自单一硅藻的𝛿30Si和Ge/Si比值。YR BP。我们研究这些数据集，以确定全新世热液活动的长期变化，以及大型和短期事件的影响，即热液和火山喷发。结合xrf和岩性资料，结合bSiO2、𝛿30Si和Ge/Si，揭示了黄石湖具有弹性的生物地球化学系统：在岩性中可以看到热液爆炸，但对bSiO2的聚集和fi30Si的特征没有明显的影响。这两个岩心显示出相似之处，表明整个湖上都有稳定而均匀的DSI来源。𝛿30Si和Ge/Si值的窄幅范围表明，该湖的生产层混合良好，生物地球化学稳定，全新世一直有较高的硅热液输入，但ffer不受干扰事件的影响。在两个岩心的𝛿-30Si化石硅藻记录中，bSiO2浓度随时间的变化与向年轻沉积物增加的相关性较弱。这一增加反映了海洋记录中看到的情况，并遵循了自冰川消融以来夏季日照、夏季温度和湖泊水柱混合的已知变化。这表明气候强迫和土壤形成最终决定了硅同位素记录，我们认为这是通过风化化学计量比、硅藻产量的变化来实现的。
isotope geochemistry has potential to provide these reconstructions, given the competing source and process controls can be deconvolved. The silica-rich volcanic and hydrothermal systems in Yellowstone National Park are a great source of dissolved silicon into Yellowstone Lake, a system with high silicon, and thus carbon, export rates and the formation of diatom–rich sediment. Yellowstone Lake sediments should be an archive of past silicon biogeochemistry, although the effect of sublacustrine hydrothermal activity or hydrothermal explosion events is unclear. Here, we analysed lake water, tributaries, and hydrothermal vent fluids from Yellowstone Lake for their dissolved Si concentrations, isotope composition ( 𝛿 30 Si ) and Ge/Si ratios to evaluate the sources of variability in the lake’s Si cycle. Bulk elemental composition and biogenic SiO 2 ( bSiO 2 ) content, together with 𝛿 30 Si and Ge/Si ratios from a single diatom species, Stephanodiscus yellowstonensis , were analysed in two sediment cores spanning the last 9880 cal. yr BP. We investigate these datasets to identify long term Holocene changes in hydrothermal activity and effects of large and short-term events i.e., hydrothermal and a volcanic eruption. Combinations of bSiO 2 , 𝛿 30 Si and Ge/Si with XRF and lithology data revealed that Yellowstone Lake has a resilient biogeochemical system: hydrothermal explosions are visible in the lithology but have no identifiable impact on bSiO 2 accumulation or on the 𝛿 30 Si signature. Both cores show similarities that suggest a stable and homogeneous dSi source across the entire lake. A narrow range of 𝛿 30 Si and Ge/Si values suggests that the productive layer of the lake was well mixed and biogeochemically stable, with consistently high hydrothermal inputs of Si throughout the Holocene to buffer against the disturbance events. Variation in bSiO 2 concentration through time is weakly correlated with an increase towards younger sediment in the 𝛿 30 Si fossil diatom record in both cores. This increase mirrors that seen in ocean records, and follows changes known in summer insolation, summer temperatures and lake water-column mixing since the deglaciation. This suggests that climate forcing, and soil formation ultimately govern the silicon isotope record, which we suggest is via a combination of changes in weathering stoichiometry, diatom production