古河道冲刷带是含煤岩系中常见的一种地质现象，不仅可以造成可采煤层几何形态的变化，而且影响煤矿安全、高效生产。因此，准确预测古河道冲刷带的空间分布一直是煤矿地质领域关心的重要问题。目前，对古河道冲刷带的预测主要采用沉积分析、地球物理及地质统计等方法。由于地下地球物理探测干扰因素多、影响地质统计数学模型的地质条件复杂，导致物探方法和地质统计方法对古河道冲刷带的预测结果存在多解性和不确定性，而沉积学分析被认为是解决古河道冲刷带分布预测问题最直接、最有效的方法。神府南区是陕北侏罗纪煤田的主要矿区之一，该区延安组含煤岩系顶部发育的直罗组砂体属辫状河-辫状河三角洲成因，其对可采煤层可以形成明显的冲刷带。以直罗组古河道含水层为水源的煤矿突水危险性较大，古河道顶板水害成为威胁矿区安全高效生产的重要致灾因素之一。然而，目前对直罗组古河道冲刷带的分布规律仍然不清楚，给该区域矿井防治水工作带来了极大的挑战。鉴于此，本文在野外地质调查、岩心编录基础上，通过砂分散体系、煤层厚度及古河道砂体与下伏地层的接触关系编图，实现对神府南区含煤岩系顶板古河道冲刷带的空间定位预测。研究发现，直罗组下段古河道以大套厚层砂体发育为主，厚度多在30~70 m，由多个正韵律旋回构成，其对下伏延安组地层产生了明显的冲刷作用，造成延安组第Ⅴ单元、第Ⅳ单元地层缺失或减薄。砂分散体系、煤层厚度及下伏地层单元及岩性分布编图表明，神府南区古河道冲刷带主要沿着红碱淖-尔林兔-锦界一线发育，古河道对延安组第Ⅴ单元完全冲刷区域的宽度为17~28 km，而对延安组第Ⅴ单元冲刷区域的宽度却更大，达到37~46 km。直罗组下段古河道冲刷带对于神府南区煤炭开采的影响是区域性的，在古河道砂体冲刷带附近进行煤炭开采时要做好煤层顶板水害防治工作。研究成果不仅对精准预测含煤岩系中古河道冲刷带的空间分布具有重要借鉴意义，而且可为神府南区煤矿安全、高效生产提供指导。

Paleochannel scouring zones have been served as a common geological phenomenon in coalbearing strata,which can not only lead to the changes of geometric shapes of coal seams,but also affect the safe and efficient production of coal mines. Therefore,the accurate prediction of spatial distribution of paleochannel scouring zones has always been an important issue in the coal mine geology. At present,sedimentary analysis,geophysical prospecting and geostatistical methods are mainly used to predict the spatial distribution of paleochannel scouring zones. Due to many interference factors in underground geophysical prospecting and complex geological conditions affecting geological statistical mathematical models,the prediction of spatial distribution of paleochannel scouring zones by the geophysical prospecting and geostatistical methods are uncertain. The sedimentological analysis has been considered as the most direct and effective method to predict the spatial distribution of paleochannel scouring zones. The southern Shenfu mining area is one of the main mining areas of the Jurassic coal field in Northern Shaanxi. Sand bodies of the Zhiluo formation developed at the top of the Yan’an Formation in the southern Shenfu mining area are formed in braided river or braided river delta,and can lead to an obvious scouring effect on the minable coal seam. The coal mines in the southern Shenfu mining area have a high risk of water inrush with the paleochannel aquifers as water source,and the roof water disaster from the paleochannels has become an important disastercausing factor which threatens the safe and efficient production in the mining area. However,the distribution of the paleochannel scouring zones is unclear,leading to a great challenge to the prevention and cure of water disaster in the mining area. In view of this,based on field geological survey and core logging,the paleochannel scouring zones of the Zhiluo Formation in the southern Shenfu mining area have been identified and predicted by the sedimentological mapping of the sand dispersion system,coal seam thickness,and contact relationship between paleochannel sand bodies and underlying strata. It is found that the ancient channel in the lower part of the Zhiluo Formation is characterized by a large set of thick sand bodies,with a thickness of 30-70 m,which is composed of several positive rhythm cycles. The ancient channels have a significant effect on the underlying Yan’an Formation,resulting in the loss or thinning of the strata in Units V and IV of the Yan’an Formation. Distribution of sand dispersion system,coal seam,underlying strata units and lithology shows that the ancient channel scouring zones in the southern Shenfu mining area mainly develops along the HongjiannaoErlintuJinjie. The width of the complete scoured zones from Units V of the Yan’an Formation is 17-28 km,but the width of its part scoured zones is 37-46 km. Effects of the paleochannel scouring zones in the lower part of the Zhiluo Formation on coal mining in the southern Shenfu mining area are regional,and the prevention and cure of roof water disaster in the process of coal mining near the paleochannel scouring zones in the southern Shenfu mining area should be done well. This research will not only serve as a reference for the accurate prediction of distribution of paleochannel scouring zones in coalbearing series,but also can provide an important guidance for the safe and efficient production of the coal mines in the southern Shenfu mining area.