大别超高压榴辉岩高温高压下电导率实验研究

为研究大陆中下地壳高导层成因及与物质组成之间的关系，用模拟实验的方法在不同的温度、压力条件下分别测定了干的和1mol/LNaCl溶液饱和的榴辉岩的电导率.结果表明，干榴辉岩平行线理方向的电导率比垂直于线理方向的高，但两个方向上的活化能相近.在中下地壳条件下，干榴辉岩的电导率比中下地壳高导层电导率值低几个数量级.常温下1mol/LNaCl溶液饱和的榴辉岩两个方向上的电导率对压力具有不同的依赖性；在中下地壳条件下，1mol/LNaCl溶液饱和的榴辉岩的电导率可达到一般高导层的电导率值.无论干的还是饱和的榴辉岩都不能解释大别山20-50km深处的高导层成因，因此，在该深度范围内榴辉岩不可能是主要的岩石组成.

EXPERIMENTAL STUDIES ON ELECTRICAL CONDUCTIVITY OF THE DABIE ULTRAHIGH-PRESSURE ECLOGITES AT HIGH PRESSURES AND HIGH TEMPERATURES

Electrical conductivity is measured for dry and saturated with 1M NaCl eclogites at various pressures and temperatures, which are prevalent in the mid and lower crust. The results show that the electrical conductivity of dry eclogites parallel to the lineation is higher than that perpendicular to the lineation, however the activation energies are similar along both directions. The conductivity of dry eclogites at conditions of the mid and lower crust is several orders of magnitude lower than that of average highly conductive layers (HCL). At room temperature, the dependence of the conductivity of saturated eclogites on pressure is different in directions parallel and perpendicular to the lineation. The conductivity of saturated eclogites at mid and lower crust conditions is in the range of values of average HCL. However, the electrical conductivity of eclogites, regardless dry or satruated, is even much lower than that of Dabieshan HCL at the depths between 20 and 50km beneath the surface, and therefore is not used to explain the genesis of this HCL. Thus eclogites are not the main rock type at such depths in Dabieshan area.