深反射大炮数据揭示北秦岭-渭河地堑-鄂尔多斯南部Moho格架

根据深地震反射数据的反射特征对布置在北秦岭-渭河地堑-鄂尔多斯南部的10个大炮(药量 ≥ 500 kg)数据进行处理,获得了反映下地壳-莫霍面结构的单次覆盖剖面。初步解释结果显示:在北秦岭,莫霍面反射的双程走时约为13 s,自南向北缓慢抬升变浅,可能表示秦岭正在经历造山后的均衡演化过程;进入渭河地堑,莫霍面加深至15 s左右,可能表明新生代形成后的莫霍面受到了强烈的挤压作用,渭河地堑两侧的莫霍面呈不对称上隆;在鄂尔多斯地块南部,莫霍面反射为14 s左右,向北有逐渐抬升的趋势,但变化平缓, 130~140 km两侧的莫霍面具有显著的反射特征差异,可能代表了渭河地堑和鄂尔多斯地块南部的深部界限。

Near vertical deep seismic reflection profile reveal the sketch of Qinling Mountains orogenic belt-Weihe garben-Ordos block's Moho by big charge shots

Ten large charge shots datas of northern Qinling-Weihe garben-southern Ordos were processed by near vertical incidence principle. We obtained a single fold section which can reveal the deep structure of this region. The section shows that the nothern Qinling orogenic belt's Moho reflection apears at 13 s(TWT)and ascend gradually from south to north. While getting into Weihe garben, the Moho reflection is deepened sharpely, and the pattern of Moho reflection looks like arc. The preliminary results shows the converge between the Oinling and Weihe garben. At the northermost of deep seismic refletion profile, the Moho reflection appears at 14 s and is deepened gradually from north to south. The Moho can not continuous tracking and Moho on both sides have different refective characterstic at 130~140 km. It likely represents the boundary between the Weihe graben and Ordos block.