Cause analysis of mineral water near Lizhuang, Qihe County

(Shandong Institute of Geology and Mineral Resources, Jinan 2500 14)

About the author: Wang Shaojuan (1976-), female, engineer, mainly engaged in research on hydrology, geothermal, environment and disaster geology.

The mineral water near Lizhuang, Qihe County has its unique forming reasons. This paper analyzes and probes into the reasons for the formation of Quaternary mineral water from two aspects of the hydraulic relationship between mineral water layer and shallow fresh water, and the relationship between mineral water aquifer and gabbro body, and further reveals the reasons for the formation of mineral water.

Keywords: Qihe; Mineral water; Form; Reason; analyse

From September to June, 2003, Shandong Institute of Geology and Mineral Resources built a deep well in Shandong Geothermal Resources Research and Development Demonstration Base, numbered Qikuang-1, with a depth of 208.39 meters and a water temperature of 16℃. The results of water quality analysis show that the strontium content in groundwater is high, which meets the relevant requirements of drinking natural mineral water (GB 8537- 1995). From 10 in 2003 to 10 in 2004, the water quality of Zhengkuang-1 mineral water was analyzed and tested in three stages: flat, dry and abundant. The results show that the strontium content in mineral water is 0.50 ~ 0.58 mg/L, which meets the relevant regulations of drinking natural mineral water standards. The water intake layer of this well is Quaternary medium coarse sand layer. According to the previous analysis of mineral water reserves in Jinan, mineral water in Jinan is generally formed in igneous rocks, marble and tertiary strata, and there are few mineral water in Quaternary. This paper discusses the formation reasons of-1 mineral water in No.7 Mine from the aspects of geological and hydrogeological conditions.

1 regional overview

The mineral water well is located in the north of Jinan, near Lizhuang, Qihe County, Dezhou City. The landform type is single, belonging to the alluvial plain of the Yellow River. The terrain is flat, and the surface lithology is mainly silt. It belongs to the continental monsoon climate zone of warm temperate zone in North China, with four distinct seasons.

Regional geological survey 1. 1

The mineral water well is located in the north wing of Taishan Uplift (Figure 1). Archean metamorphic rocks are distributed in the highest part of Taishan Uplift, and Cambrian, Ordovician, Carboniferous and Permian are distributed in the northern wing of Taishan Uplift, forming a large monoclinal structure gently inclined to the north. Influenced by Indosinian-Yanshan movement, magma invaded extensively. The strata exposed near mineral water wells are mainly Quaternary. Quaternary lithology is mainly silty clay, silty soil and silty sand, with medium-coarse sand locally, and the regional stratum thickness is 50 ~ 300 m. According to the previous research results of "Jinan Rock Mass" (Tang Licheng et al., 1990), the magma intruded from north to south in elevation angle, and the southern magma overlapped with Ordovician limestone in a gently inclined way, and became thinner from north to south. In the northern part of the rock mass, the contact with limestone gently inclines to the north and extends to the deep. According to the determination, the age of "Jinan rock mass" is 164 ~ 276 Ma, which is the product of late Indosinian-Yanshanian period. The existence of "Jinan rock mass" and the distribution of limestone provide important basic conditions for the formation of mineral water.

Figure 1 geological map of pre-Neogene bedrock in northern Jinan

1-Paleogene; 2- Cretaceous Qingshan Formation; 3- Permian; 4- Carboniferous; 5- Ordovician; 6- diorite; 7- gabbro;

8- Geological boundary; 9— Inferring fault; 10- workspace location

Hydrogeological survey 1.2

The groundwater near the mineral spring well is mainly Quaternary pore water aquifer, which is generally double-layered, and can be divided into shallow (phreatic or slightly confined water) fresh water aquifer and deep (deep confined water) fresh water aquifer.

The buried depth of shallow (phreatic or micro-confined water) freshwater aquifer floor is generally less than 50m, and the main lithology is medium sand and medium coarse sand. In the ancient river distribution area and the west of alluvial fan, the water inflow of a single well can reach 1000 ~ 3000m3/d, and the buried depth of water level is generally 3 ~ 8m, and the overall trend is gradually deepening from south to north.

The buried depth of deep fresh water (deep confined water) aquifer roof is generally about 50m, and the aquifer section is 65.30 ~ 177.30m, with fine sand, medium sand and a small amount of medium coarse sand (see Figure 2). The water level is buried at a depth of 4.90 meters and is under pressure. The atmospheric precipitation in Taiyishan area seeps into the ground and flows into the deep confined water from south to north through the bedrock fracture surface or along the bedding surface. For the vicinity of mineral water wells, the recharge direction of groundwater runoff is basically north-south, which is mainly supplied by fissure karst water of Ordovician system in the south and weathering fissure water of gabbro body.

2 Analysis of the causes of mineral water

According to the sampling analysis results of Zheng Mine-1 mineral water, the well contains many trace elements beneficial to human body, among which the strontium content reaches the national standard for drinking natural mineral water [GB 8537- 1995], which is a veritable mineral water.

Fig. 2 Borehole histogram of homogeneous ore-1 well

However, Qikuang-1 mineral water exists in Quaternary, which is different from other mineral water found in Jinan area in geological conditions. The formation of-1 mineral water in No.7 Mine is closely related to its unique geological and hydrogeological conditions, which can be analyzed from the following aspects:

2. 1 Hydraulic relationship between mineral water layer and shallow fresh water

According to the stratum data revealed by No.7 Mine 1 well, there is a silty clay layer with a thickness of about14.70m between shallow fresh water and deep water, and the buried depth of the top plate and bottom plate of this layer is 50.60m and 65.30m respectively. This layer is widely distributed, with stable lithology and good waterproof performance. There is no hydraulic connection between shallow fresh water and deep confined water, which can be seen from the following aspects:

① There is a certain difference between shallow fresh water and deep confined water; ② The hydrochemical types and contents of conventional ions and trace elements in shallow fresh water and deep confined water are quite different; (3) During the deep confined water pumping test, the shallow fresh water level remains unchanged.

2.2 Relationship between mineral water aquifer and gabbro body

(1) No.7 Mine-1 Mineral spring well is located in the north of Jinan gabbro body. The aquifer lithology of gabbro body is Su Chang gabbro, and the main mineral components are feldspar, pyroxene and mica. Its chemical composition contains 254% SiO, and the content of Sr (pro-MagmaElemental) is stable, which provides the necessary material source for the groundwater to be rich in strontium. Quaternary confined aquifer is in direct contact with gabbro in the northern part of rock mass, and has hydraulic connection with gabbro weathering fissure water, from which a large number of trace elements are obtained, which changes the water quality of deep confined water and becomes mineral water.

Fig. 3 Schematic diagram of Meng Jing-Zhouguantun geological profile.

(2) The fault on the north side of the work area generally cuts the Ordovician limestone and gabbro (see Figure 3), which connects the Quaternary pore water with the karst water in the fractures of the Ordovician limestone. Due to the action of faults, the fault structures in gabbro are very developed. At the same time, the fissure water in gabbro is hydraulically connected with the Ordovician fissure karst water, while the Quaternary is directly located on the Ordovician limestone and igneous rock, and the fissure karst water, weathered fissure water and Quaternary pore water are hydraulically connected, so that the Quaternary pore water in the working area is rich in trace elements such as strontium.

(3) The top plate of the Quaternary deep pore water aquifer in the area is a cohesive soil layer with good water-proof performance and stable distribution, which is quite different from the Quaternary shallow groundwater. Therefore, the mineral water aquifer can be well isolated and protected from shallow groundwater and surface water pollution.

(4) After the final hole of mineral water well No.7 Mine 1, use submersible pump to clean the well and pump water. The suction lasted for several days and the stable time was 48 hours. The buried depth of static water level is 4.90m, the pumping level drops by 2 1.5m, the water output 1756.80m3/d, and the water temperature is 65438+.

The above-mentioned situation shows that mineral water is underground water with deep circulation, and its formation is closely related to the action of Jinan gabbro body and fault structure. The gabbro fracture in the area forms a complex fracture system and becomes the communication channel of groundwater. Trace elements in gabbro are leached from weathered fissure water, and Quaternary pore water is further replenished, thus forming precious and relatively unique mineral water in the working area.

3 Conclusion

The formation of-1 mineral water in No.7 Mine is closely related to its geological and hydrogeological conditions. Through the investigation of mineral water in 2003 ~ 2004, the reasons for the formation of mineral water in this area were basically found out. Through the above analysis of geological and hydrogeological conditions in this area, I hope to provide reference for the exploration of Quaternary mineral water in the future.

refer to

Tang Licheng is from Liu Hongjie. 1990. On the output of Jinan gabbro. Geological Review (5)