Geographical location of Chuansha County

The Quaternary in Chuansha County is quite thick. Geological drilling and geophysical exploration reveal that the stratigraphic sequence of Chuansha is Jurassic volcanic rocks from bottom to top. Pyroclastic-sedimentary rock series, tertiary continental volcanic rock series and quaternary clay and gravel are loosely accumulated. The buried depth of bedrock is generally 300 ~ 350 meters, the shallowest in Jinqiao area is 227 meters, and the deepest near Heqing is 396 meters.

Upper Jurassic volcanic rocks and pyroclastic-sedimentary rock series are widely distributed. Laocun Formation consists of purplish red and grayish white tuffaceous sandstone and rhyolitic tuffaceous lava, which are widely distributed in western and southern China. Huangjian Formation is andesite, andesite pyroclastic rock, etc. , widely distributed in central and northeast China. The spatial distribution of Laocun Formation and Huangjian Formation is closely related to volcanic structure and regional fault structure.

The Palaeogene Miocene Bailonggang basalt is dominated by olivine basalt, mixed with dark gray and brown clay and gravel, and beaded along the fault. K-Ar ages of all basalt are 18.7Ma and 26.7Ma, which are mainly distributed in Qingdun, Bailonggang and Shiwan, with a distribution area of tens of square kilometers and a thickness of more than 250 meters.

Quaternary strata gradually thickened from Beicai to Cailu. According to the principle of climate stratigraphy, based on lithostratigraphy, combined with the signs of sporopollen and microfossils, the Quaternary system is divided into four series: Lower Pleistocene, Middle Pleistocene, Upper Pleistocene and Holocene. The development and structure of this set of loose strata have certain regularity from bottom to top in the vertical direction, which can be divided into two layers: the lower "variegated layer" with a buried depth of about150m, and the variegated clay with brownish yellow as the keynote is interbedded with gray, brownish yellow sand and gravel; Clay is hard and plastic, while sand and gravel are loose or weakly cemented. It belongs to Quaternary early Pleistocene continental deposits. The upper "gray layer", with a buried depth of about 150m, is mainly gray loam mixed with light gray and yellow gray sand; Loam is soft and plastic, and sand is loose. Since the Middle Pleistocene, it has been an alternate deposit between land and sea. During the Quaternary, the paleoclimate of Chuansha experienced eight obvious changes of cold and warm, which led to the evolution of paleogeography and sedimentary facies. Since the late Early Pleistocene, all warm periods have been accompanied by seawater intrusion, and six marine layers have been deposited. During the cold period, seawater retrogradation, river facies and lake facies were deposited. There are obvious changes throughout the year. The five-day average temperature is lower than 10℃ in winter, higher than 22℃ in summer and 10℃ ~ 22℃ in spring and autumn.

Spring: April 1 to June 4, ***65 days; Summer: June 5th to September 22nd, *** 1 10 days; Autumn: September 23rd ~165438+1October 26th, ***65 days; Winter:165438+1October 27th to March 3rd1,* * *125th days.

In spring, the temperature rises slowly and leaps by leaps and bounds, cold air activities are frequent and the weather changes a lot. As the saying goes, "three faces change in spring", it is often rainy in late spring, with less sunshine and cold weather.

In early summer, there was a time when Huang Meiyu usually bloomed in early July. July and August are hot summers and the hottest periods of the year. There was a period of drought in summer, and the precipitation was mainly local thunderstorm and typhoon rainstorm.

There is a rain in early autumn, and it is usually crisp in autumn from 10.

Winter is generally dominated by winter drought, but there are also wet winters. The coldest period is from mid-October to early February. Animals: Rats, including Rattus norvegicus, Mus musculus and Rattus norvegicus. Otter. Bat. Weasels, caves, bamboo gardens and fields. Since the land was leveled in the 1950s, pigs and badgers living in graves and mounds have been rare. Tigers, according to old books, Baoshan, Gao Qiao and Laotangbian all had tigers in the Ming Dynasty.

Birds: wild goose, swallow, pheasant, quail, pigeon, sparrow, turtledove, cuckoo, thrush, Chinese Pulsatilla, cormorant, oriole, woodpecker, crow, magpie, cuckoo and stork.

Fish: The freshwater fish in this county are grass carp, silver carp, bighead carp, carp, crucian carp, bream, perch, pond fish, mullet, bearded fish, eel and loach. Shellfish include snails, yellow clams, Hyriopsis cumingii, crested clams and toothless clams.

Amphibians and reptiles: Amphibians include frogs, golden frogs, rain frogs and toads. Reptiles include turtles, soft-shelled turtles, green-headed snakes, scale-star snakes, four-legged snakes, red-trained snakes, vipers and geckos. Annelids include earthworms, leeches and snails.

Insects: wild silkworm, bee, cricket, mantis, cicada, mole cricket, grasshopper, bean elephant, butterfly, inchworm, octopus, longicorn beetle, Mylabris, firefly, ground beetle and ant. Trees: Sophora japonica, Chinese fir, willow, Gleditsia sinensis, Holly, Dalbergia odorifera, Pterocarya stenoptera, Mulberry, Zheshu, Zhiyang, Elm (commonly known as Zelkova schneideriana), Boxwood and Platycladus orientalis.

Bamboo: bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo, bamboo.

Medicinal plants: wild Chinese herbal medicines, mainly including Atractylodis Rhizoma, Polygoni Multiflori Radix, Rhizoma Acori Graminei, Radix Ophiopogonis, Rhizoma Cyperi, Trichosanthis Radix, Perillae Herba, Semen Plantaginis, Rhizoma Arisaematis, Inula, Rhizoma Pinelliae, Rhizoma Alpiniae Officinalis, Herba Violae, Shā rotto Katakuri and Herba Elsholtzia.

Miscellaneous plants: silk grass, licorice, broom, cattail, water chestnut, water chestnut, dandelion, wild amaranth, Sichuan valley, water chestnut and so on.