Occurrence and Hydrochemical Characteristics of Saline and Salty Springs in the Sichuan Basin of China

Table 1

Simplified stratigraphic description of the Sichuan Basin.

Geologic age				Stratigraphic code	Thickness (m)	Petrographic description	Evolution stages of cap rocks	Occurrence of the springs	Sample site
Erathem	System	Series	Group
Cenozoic	Quaternary			Q	0-380	Sandstone, gravel, pebbles, and clay	Folding uplift transformation stage		Mainzhu; Chengdu
	Neogene			N	0-300	Sandstone, mudstone, and glutenite
	Palaeogene			E	0-2000	Sandstone, mudstone, and glutenite
Mesozoic	Cretaceous			K	600-1400	Mudstone, sandstone interbedded with conglomerate		Saline and salty springs	Dujiangyan
	Jurassic	Upper	Penlaizhen	J3p	340-500	Pelite, siltstone	Continental basin development stage	Saline and salty springs
		Middle	Shaximiao	J2s	600-2800	Aubergine mudstone
		Lower	Ziliujing	J1z	200-900	Sandstone, mudstone, and shale
	Triassic	Upper	Xijiahe	T3x	250-3000	Sandstone, mudstone, shale, and coal seams
		Middle	Leikoupo	T2l	900-1700	Limestone, dolomite, interbedded mud, and gypsum layer	Marine platform development stage	Saline and salty springs	Chonqqing, Yibin
		Lower	Jialingjiang	T1j		Middle thick limestone interbedded with dolomite, limestone, dolomite, and thick layer gypsum		Saline and salty springs
Paleozoic	Permian	Upper		P2	200-500	Mudstone and limestone interbedded with thin seam coal
		Lower		P1	200-500	Thick limestone-dolomite limestone		Saline and salty springs	Ya’an, Leshan
	Carboniferous			C	0-600	Mudstone, shale, and silty sandstone
	Silurian			S	0-1600	Limestone, mudstone, and shale
	Ordovician			O	0-600	Limestone, dolomite, and marlstone
	Cambrian			Є	0-2500	Clastic and carbonate rock
Proterozoic	Sinian			Z	200-1500	Dolomite, massive argillaceous dolomite, and massive dolomite with black siliceous concretion
	Presinian			Anz