Characteristics of the Paleogene water-bearing Formation in the middle and upper reaches of the Dawenhe River basin, Shandong Province

Using data of 5 drill holes of the Dawenkou and the Zhujiagou Formation, combined with data from 55 drill holes obtained in hydrogeology survey, the authors studied the characteristics of distribution, physical properties, water-bearing condition, hydrochemistry and groundwater recharge cycle of the Paleogene water-bearing formation in the middle and upper reaches of the Dawenhe River basin. The results show that the watery upper section of Dawenkou Formation is distributed in the north of the basin. The lithology of the aquifer is semi-consolidated conglomerate with HCO₃-Ca·Mg type. The Zhujiagou Formation is distributed in the depression plate of boundary faults, with good dissolution calcareous conglomerate aquifer media and complex hydrochemical types. Modern precipitation is the main source of groundwater recharge. Evaporation and concentration, dissolution of calcite, dolomite and gypsum and polluting activities have participated in the formation of hydrochemical components. This paper sums up 3 groundwater enrichment patterns of different Paleogene water-bearing formations:water controlled by structural fractures, fracture and pore water enrichment in semi-consolidated water-bearing formation, and fractured karst water enrichment in calcareous conglomerate.