Geology and structure
Since Paleozoic, this area has experienced many different tectonic movements, forming Caledonian fold uplift belt in western Guangdong, Indo-Chinese depression belt in Guangdong and Yanshan fold belt in eastern Guangdong. The zonal structural belt, meridional structural belt, Neocathaysian structure, gabled structure and NW structural traces formed by previous movements are quite common, and the phenomena of interpenetration, mutual interference and compound intersection are quite common.
There is strong magmatic activity in the area, and granite and volcanic rocks account for about 50% of the province. Magmatic activity is obviously controlled by tectonic movement. The Caledonian-Indosinian-Yanshanian magmatism was from northwest to southeast, with obvious regional zonation. The basalt erupted in Himalayan period in Leizhou Peninsula is well developed.
I. Fracture
The major deep faults in Guangdong are as follows:
Wuchuan-Sihui deep fault zone: it is distributed in the northeast direction of 20 ~ 40, with a length of more than 800 km. It runs from Wuchuan to the northeast, passes through Yangchun, Yunfu and Sihui, and is divided into two branches in Shaoguan. One branch is connected with Jiangxi Dayu-Xingguo-Cheng Nan fault along Nanxiong Basin. The other branch is inserted into Suichuan, Jiangxi Province, and connected with the Tanlu fault along the north of Ganjiang River. Granite and ultrabasic rocks are distributed along faults and are active faults. There are more than 20 hot springs exposed along the fault, and the water temperature is 23 ~ 8 1℃. The temperature in the southwest section of the fault is high, and there is a thermal anomaly area under the basalt in Lei Qiong, resulting in confined hot water.
Enping-Xinfeng fault zone: strike NE40, which is about 450 km long and 5-20 km wide in Guangdong, with NW dip and dip angle of 50-60. It enters Jiangxi northward and is connected with Dayu-Chengnan deep fault. Faults control the distribution of Kaiping, Sanshui, Gui Long and other tectonic basins. There are multi-stage magmatic rocks along the fault, which is an active fault with as many as 17 hot springs exposed. The famous Conghua Hot Spring is located on the fault zone, with the highest water temperature above 83℃.
Lianhuashan deep fault zone: strike NE 40 ~ 50, dip SE, dip angle 40 ~ 70, pass Fengshun, Meixian and Tai Po along Lianhua Mountain, and connect with Fuan-Nanjing deep fault zone in Hua 'an and Nanjing areas.
Fogang-Fengliangshen Fault Zone: Located in the line of Huaiji, Fogang, Heyuan, Wuhua, Fengshun and Chaoan, it is about 600km long and 20-70 km wide in Guangdong, and it runs east-west and controls the spatial distribution of the Late Triassic basin. There are about 30 hot springs and 2 thermal fields along the fault zone, which is a recent active fault.
Gaoyao-Huilai deep fault zone: located in Luoding, Gaoyao, Guangzhou, Huiyang, Haifeng and Huilai, the east-west trend controls the development of Mesozoic and Cenozoic basins such as Sanshui, Luoding and Dongguan, and geothermal anomalies are relatively concentrated, with 36 hot springs and 1 hot water basin.
Nan' ao deep fault zone: it is distributed in the direction of NE 45 ~ 60 along the coast of eastern Guangdong, which is a part of Changle-Nan' ao fault zone in Fujian and enters Huilai in the southwest. It is about 400 kilometers long in Guangdong.
Chaoan-Puning deep fault zone: located in Raoping, Chaoan, Puning and Lufeng areas, it enters the sea from Shanwei, and is about 2 10km long in Guangdong, with an overall strike of NE 45-50 and a dip of SE of 50-80. See figure 6- 1- 1.
Second, fold and fault basins.
1. collapse
The main folds in Guangdong are as follows:
Lianshan-Fogang-Yunan anticlinorium: It consists of Fogang anticlinorium and Fengkai-Deqing anticlinorium. The northeast can be connected with Wuyishan metamorphic rock series, and the southwest can enter Wuzhou area of Guangxi. Guangdong is about 400 kilometers long and 40-80 kilometers wide.
Jiaoling-Zengcheng-Guyao-Yunkai anticline: northeast, about 750km long and 50- 100 km wide. The northeast section enters Fujian, and the southwest section enters Hepu, Guangxi. It consists of Jiaoling-Longchuan anticlinorium, Zengcheng Uplift, Guyao anticlinorium and Yunkai Uplift. Jiaoling-Longchuan anticlinorium is adjacent to Jiulianshan anticlinorium, with Lanfangbei as the main part. The east and west sides of Zengcheng uplift and Guyao anticline are cut by Heyuan and Enping-Xinfeng fault, and the length is about 1 10km.
Figure 6-1-/structural outline map of Guangdong and Hainan (according to Guangdong Bureau of Geology and Mineral Resources 199 1)
Guyao anticlinorium: It consists of Sinian metamorphic rock series and early Paleozoic migmatite; Yunkai uplift is composed of Sinian metamorphic rock series and early Paleozoic migmatite. The original rock is a mixture of continental clastic rock formation, carbonate rock formation and volcanic rock formation, with huge thickness and deep metamorphism. The lithology is mainly granulite, marble, phyllite and schist.
Binxian-Huaiji Syncline: It is mainly composed of Jiang Ge Syncline, Xijiang Syncline, Daping Syncline, Weighing Frame Syncline, Tianlong Syncline and Tongluo Syncline. The whole NNE is composed of Devonian-Middle Triassic, and the dip angles of its wings are mostly 20 ~ 30.
Beijiang compound syncline: distributed in Renhua, Shaoguan and Yingde, mainly including Maba-Datang syncline, Lianhuashan syncline, Furong syncline, Tianziling syncline, Chongyang syncline, Xianglang syncline, Dakengkou syncline, Wang Bu syncline, Xueshan syncline, Sanjie syncline and Wengcheng syncline. It is mainly composed of short-axis pleats.
Lianjiang compound syncline: located in Lianjiang county and Zhongtong area, it is about 80km long and consists of multiple parallel folds with asymmetric wings, mainly Devonian-Permian.
Chunwan compound syncline: strike ne, with secondary folds developed, mainly including Chunwan syncline, Bamu syncline, Niujiaojian syncline and Chadong syncline. The core is composed of Carboniferous and Permian, and the two wings are Devonian. The axial plane is almost vertical.
2. Fault basin
The formation of fault basins in this area is mostly related to the large fault zone, and the development and spatial distribution of the basins are controlled by it.
The basin is controlled by (1) Lianhuashan deep fault zone.
There are mainly Caoguan Lake, Meicheng, Xingning, Wuhua, Huidong Duozhu, Huiyang Danshui, Tai Po, Hong Kong and other basins in Jiexi, which are distributed in a beaded shape among the broken beams.
Wuhua Basin: It is distributed along the fault bundle in the west of the fault zone, with an area of 380km2, and consists of Cretaceous, with rhyolite and pyroclastic rocks in the upper part, with a thickness of1100m; The lower part is brownish red clastic rock with a thickness of about 1500~2500m ~ 2500 m, which is a dustpan basin with steep east and gentle west.
Xingning Basin: located in Xingning County, with NW330 distribution and an area of about 400km2, is composed of Cretaceous red rock series, with rhyolite in the lower Cretaceous and mirabilite and gypsum in the upper Cretaceous, with the grain size from coarse to fine and then coarse, forming a complete sedimentary cycle.
(2) The basin controlled by the deep fault zone in Heyuan.
There are mainly river basins such as Heyuan, Lighthouse, Longchuan, Beiling and Plain 2 1.
Lighthouse basin: located on the west side of Heyuan fault zone, striking ne, with an area of 900km2, mainly composed of Upper Cretaceous, with a thickness of 1300 ~ 1400m.
Heyuan Basin: It is distributed in the northeast direction with an area of 725km2, which is mainly composed of Upper Cretaceous, Paleogene and Neogene. Upper Cretaceous, with a thickness of 1600 ~ 3700 m, is divided into five sections with coarse-fine-coarse grain size changes, forming a complete sedimentary cycle; Paleogene and Neogene are more than 700m thick, and there is Yangcun basalt between the above two layers, with a thickness of 150 ~ 180 m, and the bottom is Paleogene.
(3) basins controlled by Enping-Xinfengshen fault zone.
There are more than 10 river basins in Xinfeng Street, Li Anping, Gui Long, Sanshui and Kaiping.
Gui Long Basin: Located in the northern suburb of Guangzhou, northwest of Guangzhou-Conghua fault, with an area of 235km2, it is composed of Paleogene, with a thickness of 1540m and multiple layers of gypsum and mirabilite.
Kaiping Baizushan Basin: Located in Kaiping, Enping and other places, striking NE, with an area of about 900km2. It is composed of Baizushan Formation of Lower Cretaceous, with a thickness of 1800m, mixed with multiple layers of tuff and clastic tuff, showing a sedimentary cycle from coarse to fine from bottom to top, and the occurrence of rock strata in the center of the basin is nearly horizontal. After Cretaceous, the basin uplifted and the subsidence center moved to both sides, forming Cangcheng Basin and Kaiping Basin.
(4) Basin controlled by Wuchuan-Sihui deep fault.
There are mainly Nanxiong, Renhua Danxia, Yingde Shiqiao, Luoding, Maoming and other watersheds above 10.
Nanxiong Basin: Located in Nanxiong, Shixing and other places in the north of Guangdong Province, it is a typical dustpan basin with an area of about 65,438 0,800km2, which consists of Upper Cretaceous and Lower Tertiary. Upper Cretaceous, 600 ~ 2400 m thick, is divided into three sections, with coarse-fine-coarse rhythmic changes from bottom to top, forming a complete sedimentary cycle; Paleogene, continental clastic deposits.
Luoding Basin: Located in Luoding County, western Guangdong Province, it is distributed in NE direction, with an area of about 875km2. It consists of Luoding Group of Lower Cretaceous and Zhajiang Group of Upper Cretaceous, with a total thickness of over 4,800 meters. The whole set of red strata presents a rhythmic change from coarse to fine and then to coarse, forming a complete sedimentary cycle. Nanxiong fault in the northern margin of the basin controls the development of the basin.
Maoming Basin: Located in Maoming, Gaozhou, Huazhou and other places in western Guangdong, it runs northwest, covering an area of about 2000km2, and consists of Cretaceous and Paleogene. Cretaceous, with a thickness of more than 2000m, mixed with multi-layer volcanic rocks, with obvious rhythm, from bottom to top, from coarse to fine, forming a complete sedimentary cycle; Paleogene, about 2800 meters thick, sandwiched with multiple coal measures and oil shale.
(5) Faulted basins controlled by Gaoyao-Huilai deep fault.
There are mainly Huizhou, Dongguan, Sanshui and Dasha basins, forming a red basin group with Sanshui basin as the center and nearly east-west trend, covering an area of about 3075km2. Cretaceous and Paleogene are developed in the basin, the former is 4000 meters thick, and the latter is mixed with basalt, trachyte, rhyolite and volcanic rocks.
(6) Faulted basins controlled by the Qiongzhou Strait deep fault zone.
Lei Qiong fault basin is located in Qiongzhou Strait in the south of Leizhou Peninsula, with an area of10.6 million km2, which starts from Suixi deep fault in the north and ends at Wangwu-Wenjiao deep fault in the south, and is composed of Cretaceous, Paleogene, Neogene and Quaternary, forming Lei Qiong fault basin. The two sides of the basin collapsed step by step. On one side of Leizhou Peninsula, there is Zhanjiang sag with an area of 970km2 from north to south. Jijia sag covers an area of 480km2 in Wushi sag and Jinhe sag, 950km2 in Maicheng sag and piedmont sag, with an area of 1000km2. From south to north, the northern part of Hainan Island is Changpo, Fushan-Duowen and Haikou Depression. This basin is a Cenozoic rift basin.