加拿大海盆莫霍面分布特征及其构造意义

THE MOHO DEPTH IN THE CANADIAN BASIN AND ITS TECTONIC IMPLICATIONS

利用北极加拿大海盆及其周边最新的重力数据,经过水深、沉积层厚度以及平均地壳厚度的重力效应改正,收集了该地区的声呐浮标数据,数字化得到57个控制点,基于Parker方法,使用带控制点的界面反演计算了研究区的莫霍面深度。结果表明,莫霍面深度由西向东逐渐加深。边缘地与海盆西侧交界处莫霍面深度最浅,在12 km左右,说明此处可能存在补偿不足;阿拉斯加处的莫霍面深度最深,至少30 km,推测该区域受到的挤压较为强烈或者沉积物供给充足使得地壳增厚。深度值变化与其洋壳-洋陆过渡带-陆壳的地壳结构变化也相吻合,支持了逆时针旋转模式。

We correct their gravitational effect of the water depth,sediment thickness and average crustal thickness using the latest gravity data from the Arctic Canada Basin and its surrounding areas.And then we collect the sonar buoy data of the area and digitize 57 control points.We calculate the Moho depth of this area using the interface with controlling point based on the Parker method.The results show that the Moho depth gradually deepens from west to east .It’s shallowest at the junction between the edge and the west of the basin,about 12 km,indicating that there may be insufficient compensation.The Moho in Alaska has the deepest depth,at least 30km,supposing that the area is more strongly squeezed or abundant supplies of sediment thickens the crust.The change of depth is consistent with the changes in the crust structure of the oceanic- continental transition zone-continental crust,which supports a counterclockwise rotation pattern.