Microstructure of high-temperature (>73 °C) siliceous sinter deposited around hot springs and geysers, Yellowstone National Park: the role of biological and abiological processes in sedimentation
Microstructure of high-temperature (>73 °C) siliceous sinter deposited around hot springs and geysers, Yellowstone National Park: the role of biological and abiological processes in sedimentation
复制标题
黄石国家公园温泉和间歇泉周围沉积的高温（>73°C）硅质烧结体的微观结构：生物和非生物过程在沉积中的作用
DOI：
10.1139/e03-066
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发表时间：
2003
影响因子：
1.4
通讯作者：
Deena Braunstein
中科院分区：
文献类型：
--
作者：
D. Lowe;Deena Braunstein
黄石国家公园的微碱性温泉和间歇泉显示出独特的高温（> 73 ° C）硅质烧结物组合，反映了当地的水动力条件。主要沉积区包括水下水池和水道底部以及间歇性湿润的陆上飞溅、涌浪和溢流区。水下沉积物包括颗粒硅质沉积物和树枝状和微生物硅骨架。二氧化硅骨架形成薄的、多孔的、富含微生物的膜，覆盖在水下表面。在飞溅区中，具有狭窄裂缝的针状体占主导地位。涌浪和溢流沉积物包括池和水道边缘、柱状物和丘状物。在薄片中，陆上烧结物由以下组成：（i）沉积在表面上的深棕色、几乎不透明的层状烧结物，其蒸发至干燥;（ii）通过过饱和驱动的沉淀而在水下沉积的透明半透明二氧化硅;（iii）异质二氧化硅，代表二氧化硅结壳的微生物细丝和碎屑;以及（iv）烧结物碎片。褐色纹层形成了大多数沉积在涌流带和溢流带的烧结矿的骨架。坑穴是陆上烧结矿常见的结构特征，表现为上凹的假交错纹层和迁移形成的微不整合。沉积在蒸发至干燥的表面上的二氧化硅的显著双折射可能是应变效应。反复的润湿和蒸发，经常干燥，和毛细管效应控制的沉积，形态和显微结构的最高温烧结完全水下区域以外。微生物细丝丰富的高温烧结，但不提供主要的控制形态或结构，除了在水下表面上开发的生物膜。许多高温烧结矿的毫米级纹层旋回性代表了二氧化硅沉积的年度分层和定期的季节性波动。
Slightly alkaline hot springs and geysers in Yellowstone National Park exhibit distinctive assemblages of high-temperature (>73 °C) siliceous sinter reflecting local hydrodynamic conditions. The main depositional zones include subaqueous pool and channel bottoms and intermittently wetted subaerial splash, surge, and overflow areas. Subaqueous deposits include particulate siliceous sediment and dendritic and microbial silica framework. Silica framework forms thin, porous, microbe-rich films coating subaqueous surces. Spicules with intervening narrow crevices dominate in splash zones. Surge and overflow deposits include pool and channel rims, columns, and knobs. In thin section, subaerial sinter is composed of ( i ) dark brown, nearly opaque laminated sinter deposited on surfaces that evaporate to dryness; ( ii ) clear translucent silica deposited subaqueously through precipitation driven by supersaturation; ( iii ) heterogeneous silica representing silica-encrusted microbial filaments and detritus; and ( iv ) sinter debris. Brownish laminations form the framework of most sinter deposited in surge and overflow zones. Pits and cavities are common architectural features of subaerial sinter and show concave-upward pseudo-cross-laminations and micro-unconformities developed through migration. Marked birefringence of silica deposited on surfaces that evaporate to dryness is probably a strain effect. Repeated wetting and evaporation, often to dryness, and capillary effects control the deposition, morphology, and microstructure of most high-temperature sinter outside of the fully subaqueous zone. Microbial filaments are abundant on and within high-temperature sinter but do not provide the main controls on morphology or structuring except in biofilms developed on subaqueous surfaces. Millimetre-scale lamination cyclicity in much high-temperature sinter represents annual layering and regular seasonal fluctuations in silica sedimentation.