The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia
The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia
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DOI：
10.1016/j.palaeo.2020.109905
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发表时间：
2020-10
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通讯作者：
J. Russell;H. Vogel;S. Bijaksana;M. Melles;A. Deino;A. Hafidz;D. Haffner;Ascelina K. M. Hasberg;Marina A. Morlock;T. Rintelen;R. Sheppard;Björn Stelbrink;J. Stevenson
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作者：
J. Russell;H. Vogel;S. Bijaksana;M. Melles;A. Deino;A. Hafidz;D. Haffner;Ascelina K. M. Hasberg;Marina A. Morlock;T. Rintelen;R. Sheppard;Björn Stelbrink;J. Stevenson
东南亚缺乏长期和连续的大陆记录，适合了解该地区气候的过去变化和根本原因，以及第四纪晚期相关的多样生态系统演化。2015年，Towuti钻探项目（TDP）从苏拉威西岛的Towuti湖（印度尼西亚最古老的湖泊之一）收集了一系列沉积岩心。钻孔岩心包含约100万年的不间断湖泊沉积，以记录热带西太平洋的长期环境和气候变化，地质和环境变化对水生生物类群生物进化的影响，以及富含金属的超镁铁质湖泊沉积物的地质微生物学和地球化学。在这里，我们使用岩石地层学，矿物学，地球化学和地质年代学数据集来阐明Towuti湖的构造出现和湖泊形成以来的气候和火山强迫的地球化学反应。我们的数据文件，Towuti湖出现在一个阶段的加速构造沉降的景观，其特点是活跃的河道，浅湖和沼泽成一个永久性的湖泊在~1马。湖相沉积物的特点是准韵律交替的绿色有机丰富和红色菱铁矿粘土床，反映了湖泊混合和地球化学的变化，作为对温度和水文变化的响应，由轨道尺度的变化驱动的太阳能和大陆冰量通过中晚更新世。粘土沉积被两层泥质软泥打断，泥质软泥主要由硅藻组成，反映了初级生产力大幅提高的阶段。与多个火山灰层密切相关的这些钙质软泥的出现表明，由于火山源P的增加，可能与支持P循环的湖泊混合状态相结合。关于湖泊年龄和个体发育的数据也与分子钟估计的~ 0.7Ma一致（0.18-1.37马）的分歧湖Towuti的Telmatherinid鱼类从河流的祖先。因此，我们的数据是兼容的进化模型中，湖Towuti的特有动物是地理物种形成的结果，在马利利湖，一组大型湖泊在东南苏拉威西岛，由物理或化学扩散限制所施加的区域河流和湖泊。目前正在编制更详细的年代限制和更精确的气候和环境代用数据集，这将有助于在今后的研究中更详细地描绘该区域的气候和环境历史。
There is a paucity of long and continuous continental records from South East Asia suitable to inform on past changes and underlying causes of the region's climate and associated diverse ecosystem evolution during the late Quaternary. In 2015, the Towuti Drilling Project (TDP) collected a series of sedimentary drill cores from the tectonic, ferruginous, and highly biodiverse Lake Towuti, Sulawesi, one of Indonesia's oldest lakes. The drill cores contain ~1 Myr of uninterrupted lacustrine sedimentation to document long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediment. Here we use lithostratigraphic, mineralogical, geochemical, and geochronological datasets to elucidate Lake Towuti's tectonic emergence and its biogeochemical responses to climatic and volcanic forcings since lake formation. Our data document that Lake Towuti emerged during a phase of accelerated tectonic subsidence from a landscape characterized by active river channels, shallow lakes and swamps into a permanent lake at ~1 Ma. The lacustrine sediments feature quasi-rhythmic alternations of green organic rich and red sideritic clay beds reflecting changes in lake mixing and biogeochemistry as a response to temperature and hydrological changes driven by orbital-scale changes in insolation and continental ice volume through the mid- to late Pleistocene. Clay deposition is interrupted by two beds of diatomaceous oozes composed primarily of planktonic diatoms that reflect phases of substantially increased primary productivity. The occurrence of these diatomaceous oozes in close association with multiple tephra beds suggests a trophic state change driven by the addition of volcanically sourced P, possibly in combination with a lake mixing state that supports recycling of P. Data on lake age and ontogeny are also in agreement with molecular-clock estimates of ~0.7 Ma (0.18–1.37 Ma) for the divergence of Lake Towuti's Telmatherinid fishes from a riverine ancestor. Our data therefore are compatible with an evolutionary model in which Lake Towuti's endemic fauna is a result of geographic speciation in the Malili Lakes, a set of large lakes in Southeast Sulawesi, driven by physical or chemical dispersal limits imposed by the regional rivers and lakes. More detailed chronological constraints and refined climate and environmental proxy datasets are currently in preparation and will help to paint a more detailed history of the region's climate and environmental history in future studies.