广东省丹霞地貌的地质构造背景和分区研究

Geological Tectonic Setting and Zoning of Danxia Landform in Guangdong Province

广东省共有丹霞地貌67处,分布在22个断陷盆地中,主要受古近纪―新近纪抬升区、5条北东向深大断裂和1条东西向深断裂控制,地层层位以丹霞组和南雄群为主,岩性以砾岩、砂砾岩、砂岩为主。古近纪―新近纪地壳升降运动控制了丹霞地貌在区域上的总体分布,大致以22.5°N为界线,以北为抬升区,发育丹霞地貌,以南为沉降区,不发育丹霞地貌;晚更新世以来的地壳升降运动,造成不同地区丹霞地貌的数量和规模有所区别:粤北、粤东北为抬升区,发育数量多、规模较大;粤中为沉降区,发育数量少、规模较小。深大断裂控制断陷盆地的分布,从而控制丹霞地貌具体的发育位置。根据地质构造背景和丹霞地貌发育特征,可将广东省划分为4个丹霞地貌发育区:粤北区、粤中区、粤东北区和粤西区。

Guangdong Province has a total of 67 places of Danxia landform, which are located in 22 faulted basins and mainly controlled by five north-east deep fractures and one east-west deep fracture in the Paleogene - Neogene uplift area. The strata are mainly Danxia Formation and Nanxiong Group and the lithologies are mainly conglomerate, gravel, and sandstone. The overall distribution of Danxia landform in the region is controlled by the Paleogene-Neogene crustal up-and-down movement, which is bounded by the line of 22.5~N. The area to the north of the line is uplift zone with great development of Danxia landform while that to the south of the line is settlement area without Danxia landform. The crustal up-and-down movement since late Pleistocene has led to the difference in number and size of different regions of Danxia landform： The northern and northeastern Guangdong are uplift areas where Danxia landform is more in number and larger in size, while the central Guangdong is settlement area where Danxia is less in number and smaller in size. Deep fractures control the distribution of faulted basins, which then control the development position of Danxia landform. According to the geological tectonic setting and the development characteristics of Danxia landform, Guangdong Province can be divided into four Danxia landform development areas： northern district, central district, northeast district and western district of Guangdong.