图  1  青藏高原构造单元及双湖地区位置图

1—逆冲断层；2—走滑断层；SKS—南昆仑缝合带；HJS—可可西里−金沙江缝合带；BNS—班公−怒江缝合带；YZS—雅鲁藏布江缝合带；MBT—主边界断裂

Figure  1.  Tectonic units of the Tibetan Plateau and location of the Shuanghu area

1–thrust fault; 2–strike-slip fault; SKS–South Kunlun Suture; HJS–Hoh xil–Jinsha River Suture; BNS–Bangong–Nujiang Suture; YZS–Yaluzangbu Suture; MBT–Main Boundary Thrust

图  2  青藏高原腹地双湖地区逆冲推覆构造纲要图

1—逆冲断层；2—飞来峰；3—构造窗；4—背斜；5—向斜；6—古近纪火山岩；7—晚白垩世火山岩；8—古近纪花岗岩；9—晚三叠世花岗岩；10—古生代蛇绿岩套；11—现今湖泊；AB—二维地震解释剖面；BAPS—比洛错−昂达尔错古油藏推覆体；DST—蒂让碧错−雅曲南逆冲断裂；DTT—达沃错−吐错逆冲断裂；DQT—多玛−其香错逆冲断裂; Q—第四系；E₃—渐新统（唢呐湖组）；E_1-2—古新统—始新统（康托组）；K₂—上白垩统（阿布山组）；T—三叠系；P₂—上二叠统；C-P—石炭系—二叠系；Pzm—古生界变质岩；$\gamma_5^1 $—三叠纪花岗岩；$\gamma_6^{1-2} $—古近纪花岗岩北羌塘坳陷侏罗系：J₃—上侏罗统（索瓦组J₃s与白龙冰河组J₃b）；J₂—中侏罗统（夏里组J₂x与布曲组J₂b）；J₁—下侏罗统（雀莫错组）南羌塘坳陷侏罗系：J_2-3—中—上侏罗统；J₁q—曲色组

Figure  2.  Schematic map of thrust nappe structures in the Shuanghu area, central Tibetan Plateau

1–thrust fault; 2–nappe; 3–tectonic window; 4–anticline; 5–syncline; 6–Paleogene volcanic rock; 7–Late Cretaceous volcanic rock; 8–Paleogene granite; 9–Late Triassic granite; 10–Paleozoic ophiolite; 11–present lake; AB–cross-section inferred from a seismic reflection profile; BAPS– Bilo Co–Andar Co Paleo-petroliferous System; DST–Dirangbi Co–South Yaqu Thrust; DTT–Dawo Co–Tu Co Thrust; DQT–Duoma–Qixiang Co Thrust; Q–Quaternary; E₃–Oligocene (Suonahu Formation); E_1-2–Paleocene–Eocene (Kangtuo Formation); K₂–Upper Cretaceous (Abushan Formation); T–Triassic; P₂–Upper Permian; C–P–Permian–Carboniferous; Pzm–Paleozoic metamorphic rocks; $\gamma_5^1 $–Triassic granite; $\gamma_6^{1-2} $–Paleogene granite; J₃–Upper Jurassic (Suowa Formation J₃s and Bailongbinghe Formation J₃b); J₂–Middle Jurassic (Xiali Formation J₂x and Buqu Formation J₂b); J₁–Lower Jurassic (Quemo Co Formation); J_2-3–Upper–Middle Jurassic; J₁q–Lower Jurassic Quse Formation

图  3  雀尔茶卡北侧古近纪推覆构造照片（观测点位置见图2）

J₂x—中侏罗统夏里组；E_1-2k—古新统—始新统康托组a—达沃错—吐错逆冲前陆红层沉积（镜向北东）；b—中侏罗统夏里组推覆体下伏古近系康托组磨拉石建造（镜头向北）

Figure  3.  Photos of a Paleogene thrust north of the Queerchaka (The location where the photos were taken is marked in Fig. 2)

(a) Foreland redbeds at the southern DTT margin (view to the northeast); (b) Paleogene molasse deposits of the Kangtuo Formation beneath the nappe of the Middle Jurassic Xiali Formation (view to the north) J₂x–Middle Jurassic Xiali Formation; E_1-2k–Paleocene–Eocene Kangtuo Formation

图  4  蒂让碧错西南侧晚白垩世逆冲推覆构造照片（观测点位置见图2）

Gyp—石膏；K₂a—上白垩统阿布山组；J₂x—中侏罗统夏里组a—中侏罗统夏里组飞来峰（镜头向南）；b—推覆体下伏上白垩统阿布山组磨拉石建造（镜向南西）；c—夏里组推覆体底部石膏片岩（镜头向西）

Figure  4.  Photos of a Late Cretaceous thrust southwest of the Dirangbi Co (The location where the photos were taken is marked in Fig. 2)

(a) Nappe of the Middle Jurassic Xiali Formation (view to the south); (b) Upper Cretaceous molasse deposits of the Abushan Formation beneath the nappe (view to the southwest); (c) Gypsum schist of the lower nappe of the Xiali Formation (view to the west) Gyp–gypsum; K₂a–Upper Cretaceous Abushan Formation; J₂x–Middle Jurassic Xiali Formation

图  5  双湖东侧地震测线AB地质构造剖面图

BAPS—比洛错−昂达尔错古油藏推覆体；DST—蒂让碧错−雅曲南晚白垩世逆冲推覆构造；DTT—达沃错−吐错古近纪逆冲推覆构造；DQT—多玛−其香错逆冲断裂E₃—渐新统；E_1-2k—古新统—始新统康托组；K₂a—上白垩统阿布山组；J₃s—上侏罗统索瓦组；J₂x—中侏罗统夏里组；J₂b—中侏罗统布曲组；J₁q—下侏罗统雀莫错组；T₃nd—上三叠统那底岗日组；T_2-3x—中—上三叠统肖茶卡组；C-P—石炭系—二叠系；Pz—古生界；T₃—J₁—上三叠统—下侏罗统；其他地质代号及剖面AB位置如图2

Figure  5.  Geological cross-section along seismic profile AB east of Shuanghu

BAPS–Bilo Co–Andar Co terrane bearing a paleo-oil reservoir; DST–Dirangbi Co–South Yaqu Thrust; DTT–Dawo Co–Tu Co Thrust; DQT– Duoma–Qixiang Co Thrust E₃–Oligocene; E_1-2k–Paleocene–Eocene Kangtuo Formation; K₂a–Upper Cretaceous Abushan Formation; J₃s–Upper Jurassic Suowa Formation; J₂x–Middle Jurassic Xiali Formation; J₂b–Middle Jurassic Buqu Formation; J₁q–Lower Jurassic Quemo Co Formation; T₃nd–Upper Triassic Nadigangri Formation; T_2-3x–Middle–Upper Triassic Xiaochaka Formation; C–P–Permian–Carboniferous; Pz–Paleozoic; T₃–J₁–Upper Triassic–Lower Jurassic; The locations of the other symbols and the AB profile are shown in Fig. 2.