section_path: Geography/Geology
section_name: Geology
paragraph_text: Geology
  
  The island was part of the very ancient Precambrian continent of Laurentia, the eastern core of which forms the Greenland Shield, while the less exposed coastal strips became a plateau. On these ice-free coastal strips are sediments formed in the Precambrian, overprinted by metamorphism and now formed by glaciers, which continue into the Cenozoic and Mesozoic in parts of the island.
  
  In the east and west of Greenland there are remnants of flood basalts and igneous intrusions, such as the Skaergaard intrusion. Notable rock provinces (metamorphic igneous rocks, ultramafics, and anorthosites) are found on the southwest coast at Qeqertarsuatsiaat. East of Nuuk, the banded iron ore region of Isukasia, over three billion years old, contains the world's oldest rocks, such as greenlandite (a rock composed predominantly of hornblende and hyperthene), formed 3.8 billion years ago, and nuummite. In southern Greenland, the Illimaussaq alkaline complex consists of pegmatites such as nepheline, syenites (especially kakortokite or naujaite) and sodalite (sodalite-foya). In Ivittuut, where cryolite was formerly mined, there are fluoride -bearing pegmatites. To the north of Igaliku, there are the Gardar alkaline pegmatitic intrusions of augite syenite, gabbro, etc.
  
  To the west and southwest are Palaeozoic carbonatite complexes at Kangerlussuaq (Gardiner complex) and Safartoq, and basic and ultrabasic igneous rocks at Uiffaq on Disko Island, where there are masses of heavy native iron up to 25 t (28 short tons) in the basalts.
  
  The palaeontology of East Greenland is specially rich, with some of the early tetrapods such as the Acanthostega and Ichthyostega from the Devonian and unique Triassic animals such as the phytosaur Mystriosuchus alleroq and the dinosaurs Issi saaneq and tracks.
  
  The island was part of the very ancient Precambrian continent of Laurentia, the eastern core of which forms the Greenland Shield, while the less exposed coastal strips became a plateau. On these ice-free coastal strips are sediments formed in the Precambrian, overprinted by metamorphism and now formed by glaciers, which continue into the Cenozoic and Mesozoic in parts of the island.
  
  In the east and west of Greenland there are remnants of flood basalts and igneous intrusions, such as the Skaergaard intrusion. Notable rock provinces (metamorphic igneous rocks, ultramafics, and anorthosites) are found on the southwest coast at Qeqertarsuatsiaat. East of Nuuk, the banded iron ore region of Isukasia, over three billion years old, contains the world's oldest rocks, such as greenlandite (a rock composed predominantly of hornblende and hyperthene), formed 3.8 billion years ago, and nuummite. In southern Greenland, the Illimaussaq alkaline complex consists of pegmatites such as nepheline, syenites (especially kakortokite or naujaite) and sodalite (sodalite-foya). In Ivittuut, where cryolite was formerly mined, there are fluoride -bearing pegmatites. To the north of Igaliku, there are the Gardar alkaline pegmatitic intrusions of augite syenite, gabbro, etc.
  
  To the west and southwest are Palaeozoic carbonatite complexes at Kangerlussuaq (Gardiner complex) and Safartoq, and basic and ultrabasic igneous rocks at Uiffaq on Disko Island, where there are masses of heavy native iron up to 25 t (28 short tons) in the basalts.
  
  The palaeontology of East Greenland is specially rich, with some of the early tetrapods such as the Acanthostega and Ichthyostega from the Devonian and unique Triassic animals such as the phytosaur Mystriosuchus alleroq and the dinosaurs Issi saaneq and tracks.