COCORP deep reflections: Moho at 50 km (16 S) beneath the Colorado Plateau
COCORP deep reflections: Moho at 50 km (16 S) beneath the Colorado Plateau
复制标题
COCORP 深度反射：科罗拉多高原下方 50 公里（南纬 16 公里）处的莫霍面
DOI：
--
复制
发表时间：
1989
期刊：
影响因子：
--
通讯作者：
J. Lundy
中科院分区：
文献类型：
--
作者：
E. Hauser;J. Lundy
科罗拉多高原的COCOROP深反射数据显示，复杂的反射约为16个S双向旅行时(50+公里)，超过这一点，反射率急剧下降。这一边界被解释为代表莫霍面，这一推断与现有但有限的折射数据集相一致，当它们与最近独立测定的科罗拉多高原下8.10-8.15公里/S的Pn速度相一致时。科罗拉多高原至莫霍面50公里处的∼速度和8.10-8.15公里/S的Pn速度与落基山脉以东的高平原非常相似。莫霍面上没有连续的强反射，这表明科罗拉多高原下的莫霍面是一个过渡带，而不是反射实验尺度上的速度阶跃函数。反射边界可能代表了地壳和壳-幔转换的复杂和不连续的反射体的底部，在其下面的地幔可能主要是速度为8.1kM/S的橄榄岩，这些结果有力地支持了在相对稳定的大陆地区的深反射资料上的莫霍面是以反射率的突然下降为特征的，低于该值的地幔在地震上是相对透明的。
COCORP deep reflection data on the Colorado Plateau reveal complex reflections to about 16 s two-way travel time (50+ km), beyond which there is an abrupt decrease of reflectivity. This boundary is interpreted to represent the Moho, an inference consistent with the existing but limited refraction data sets when they are reconciled with the recent independent determination of an 8.10–8.15 km/s Pn velocity beneath the Colorado Plateau. This ∼50 km depth to Moho and 8.10–8.15 km/s Pn velocity for the Colorado Plateau closely resembles that of the High Plains just east of the Rocky Mountains. The absence of continuous strong reflections at the Moho suggests that the Moho beneath the Colorado Plateau is a transition, not a velocity step function on the scale of the reflection experiment. The reflection boundary may represent the base of complex and discontinuous reflectors of the crust and crust/mantle transition, below which the mantle may be largely peridotite with a velocity of 8.1 km/s. These results strongly reinforce the suggestion that the Moho on deep reflection data in relatively stable continental regions is represented by an abrupt decrease in reflectivity, below which the mantle is relatively seismically transparent.