On the partitioning of heat flux between diffuse and point source seafloor venting
On the partitioning of heat flux between diffuse and point source seafloor venting
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DOI：
10.1029/92jb00889
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发表时间：
1992-08
影响因子：
--
通讯作者：
A. Schultz;J. Delaney;R. E. McDuff
中科院分区：
文献类型：
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作者：
A. Schultz;J. Delaney;R. E. McDuff
在北纬47°57‘，西经129°06’W的Juan de Fuca山脊奋进段的大型排气场内的温水流源上首次获得了扩散水热渗流速度和温度的直接时间序列测量。新研制的仪器利用电磁感应原理测量小尺度流量的变化，以及一组完整的热电偶和热敏电阻，直接安装在硫化物建筑物的顶部，从那里观察到强烈的扩散水热渗流。在1988年7月19日至9月2日期间，连续采集了流出物的温度和速度的样本。温度被发现受到半日潮汐周期变化的影响。温度和速度信号之间的一致性在超过12小时的周期内很强，两个信号之间有很强的负相关，而在较短的周期内没有明显的相关性。出水温度在7°C到13°C之间变化，垂直流出速度在0.07m到0.15m S−1之间变化。对温度和速度记录中的瞬变事件的检查表明，流出流量的短时间尺度变化似乎导致了流体温度的相应脉冲。结果表明，流出水温度变化与局部地震活动的高能幕总体上是同步的。最后，从硫化物顶部流出的热流密度约为2~4 mW m−2，算术平均值为2.91(±0.2 3)mW m−2。对该喷口区域点源“烟囱”喷口的研究，以及对扩散和点状热源的广泛地质填图，我们推断，扩散流出系统的热流可能比高温喷口的热流高5倍。
The first direct time series measurements of diffuse hydrothermal percolation velocities and temperatures have been obtained from a warm effluent source within a large vent field at the Endeavour Segment of the Juan de Fuca Ridge, 47°57′N, 129°06′W. A newly developed instrument using principles of electromagnetic induction to measure variations in small scale flow rates, and an integral array of thermocouples and thermistors, was emplaced directly atop a sulfide edifice from which vigorous diffuse hydrothermal percolation was observed. Samples of effluent temperatures and velocities were collected continuously for the period July 19 through September 2,1988. Temperatures were found to be modulated by variations at semidiurnal tidal periods. The coherence between temperature and velocity signals was found to be strong at periods longer than 12 hours with a strong negative correlation between the two signals and no significant coherence at shorter periods. Effluent temperatures were found to vary from about 7°C to 13°C, and vertical effluent velocities were found to vary between 0.07 and 0.15 m s−1. Examination of transient events in the temperature and velocity records indicates that short time scale variations in effluent discharge rates appear to lead corresponding pulses in fluid temperature. A general synchronicity between effluent temperature variations and an energetic episode of local seismicity is indicated. Finally, the heat flux density from the top of the sulfide body due to this diffuse mode of effluent discharge was found to vary between about 2 and 4 MW m−2, with an arithmetic mean value of 2.91 (±0.23) MW m−2. Studies of point source “smoker” venting in this vent field, as well as extensive geological mapping of diffuse and point hydrothermal sources leads us to infer that heat flow out of the system due to diffuse mode flow may exceed that due to high-temperature venting by a factor of 5.