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洋底特殊环境的限制使数值模拟成为研究海底热液对流与成矿机制的有效方法.本文通过数值模拟的方法,研究洋壳渗透率单因素变化对热液对流系统的形态和输出参数(热液喷发温度和热流值)进行研究.模拟结果表明,洋壳平均渗透率分别与热液喷发温度和热量输出呈反相关和正相关关系,符合达西流体热对流的基本解析规律.另外,洋壳渗透率的垂向变化不会使洋壳内部的对流系统产生明显的横向偏移,只使热液羽规模在垂向上产生规律性变化,且渗透率越大,热液羽规模越小.渗透率在水平方向的变化则是引发热液羽和热液喷发位置横向偏移的主要因素,且只有在特定的渗透率水平变化率范围内,上涌热液羽才会发生向高渗区的明显偏移,这也从一定程度上解释了现今拆离断层相关的热液系统均未发育于断层终止线上的事实.以大西洋Trans-Atlantic Geotraverse(TAG)热液区为例,断裂带高渗区必然影响相邻洋壳内部热液的上涌路径,但受区内拆离断裂带周缘的渗透率水平变化规律的影响,上涌热液羽不至于完全偏移至断裂带,从而产生拆离断层上盘的热液活动. 相似文献
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The sudden release of superheated fluids at depth can cause surface disturbances in the form of vents, mud volcanoes, or seafloor pockmarks. I have performed calculations with the Sage hydrocode (from Los Alamos and Science Applications International) of superheated venting in an idealised geometry, varying the pressure and velocity of hot fluid injected at depth. The simulations show several different patterns of propagation and fracturing in the deformable overburden. The simulations performed so far show, for different conditions, upward-propagating cylindrical pipes with hardened walls, narrowly diverging conical pipes, cone sheets, downward-propagating cracks, and funnel-shaped craters. 相似文献
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《国际泥沙研究》2016,(3):195-204
Reservoir sedimentation is an issue that dam operators are increasingly facing as dams are aging. Not only does it reduce a reservoir's capacity but it also affects its outlet structures such as bottom outlets and powerhouse intakes. Sedimentation may also impoverish downstream ecosystems. For these reasons, several strategies for sediment management are being investigated and applied worldwide. Among these methods, venting of turbidity currents reaching the dam can be very beneficial and economical. This measure helps in preserving a certain continuity of sediment transport in rivers obstructed by dams. However, several practical but also theoretical challenges hamper this technique, rendering its use less common and its aspects rela-tively unknown. The present paper aims to gather the actual state-of-the-art concerning turbidity currents venting and to present an outlook for future development and research in this field. 相似文献
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Multichannel seismic reflection data from the continental margin of western India suggest the potential presence of fluid
expulsion features, which may or may not be associated with gas hydrates. No typical bottom simulating reflector was observed
on the reflection seismic section. As a result we look for other evidence in seismic sections in a small corridor of the western
continental margin of India in order to establish the presence of gas hydrates. We study features including venting through
the seafloor, pockmarks, sea floor collapse, faults acting as migration paths for fluid flow, transparent gas-charged sediment,
reduction in amplitude strength, diapirism and mud-volcano. Presence of all these gas-escape features on a seismic section
implies the probable presence of methane within the zone of hydrate stability field. 相似文献
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