19. REGIONAL HEAT FLOW IN THE VICINITY OF THE CHILE TRIPLE JUNCTION CONSTRAINED BY THE DEPTH OF THE BOTTOM-SIMULATING REFLECTION 1
19. REGIONAL HEAT FLOW IN THE VICINITY OF THE CHILE TRIPLE JUNCTION CONSTRAINED BY THE DEPTH OF THE BOTTOM-SIMULATING REFLECTION 1
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发表时间：
1995
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通讯作者：
N. Bangs;K. Brown
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作者：
N. Bangs;K. Brown
深度的底部模拟反射（BSR）观察到的地震反射数据在整个智利三重结区域被用来估计的温度在该基地的天然气水合物的稳定性场，并计算区域的热流模式。Brown等人（本卷）校准了BSR的温度-深度条件，我们使用该条件来估计BSR深度的温度。根据地震到达时间估计BSR深度所需的地震速度信息和热导率数据由141航次钻井提供。热流模式在整个达尔文断裂带变化很大。在达尔文自由区北部，沿着743地震测线，热流沿增生楔呈向海递减趋势，从距楔趾30 km处的80 mW/m2降至距楔趾10 km处的40 mW/m2。热流的减少是相反的，从下面的洋壳的年龄变化的预期，被解释为低，因为最近的构造增厚的增生复合体。在断裂带以南，热流反映了下面的洋壳的年轻年龄，因为它显示出向海增加的趋势，从斜坡中部的-80 mW/m2增加到海沟斜坡趾部的高达200 mW/m2，并随着地壳年龄的减小而增加。达尔文禁区以南的热流等值线。平行于智利海脊，除了变形锋附近，热流等值线沿着变形锋。我们把变形锋附近的热流模式归因于楔趾附近孔隙流体的对流热输运。构造增厚对达尔文F. Z南部的热流没有明显的影响。在其北部，构造增厚可能不那么活跃。
The depth of the bottom-simulating reflection (BSR) observed from seismic-reflection data throughout the Chile Triple Junction region is used to estimate the temperature at the base of the gas hydrate stability field and to calculate the regional pattern of heat flow. Brown et al. (this volume) calibrate temperature-depth conditions at the BSR, which we use to estimate temperatures from BSR depths. Seismic velocity information needed to estimate BSR depths from seismic arrival times, and thermal conductivity data are provided by Leg 141 drilling. The heat-flow pattern varies greatly across the Darwin Fracture Zone. North of the Darwin F.Z., along seismic Line 743, heat flow shows a seaward decreasing trend across the accretionary wedge from 80 mW/m2 30 km from the wedge toe, to 40 mW/m2 10 km from the wedge toe. The decrease in heat flow is opposite to what is expected from the age variation of the underlying oceanic crust and is interpreted to be low because of recent tectonic thickening of the accretionary complex. South of the fracture zone, heat flow reflects the young age of the underlying oceanic crust as it shows a seaward increasing trend from -80 mW/m2 in the mid slope area to as high as 200 mW/m2 at the toe of the trench slope, increasing with decreasing age of the crust. Heat flow contours south of the Darwin F.Z. parallel the Chile Ridge, except near the deformation front; where heat flow contours are oriented along the deformation front. We attribute the heat flow pattern near the deformation front to advective heat transport from pore fluids escaping near the wedge toe. Tectonic thickening does not have as noticeable an effect on the heat flow south of the Darwin F.Z. as north of it, and tectonic thickening may be less active near the triple junction.