Sip back as we discover central Asia and explore China’s autonomous region of Inner Mongolia or Nei Mon Gu as it's spoken in Chinese. This part of the world is probably more synonymous for Genghis Khan the 13th Century warlord and warrior king than dinosaurs. Inner Mongolia forms a high inland plateau spread across almost 3,000 kilometres making it the third largest province in China. Inner Mongolia's landscape has today a stark, natural and ancient beauty with its vast and diverse ecosystems of grasslands, rugged mountain ranges, arid desert dunes and a southern border partially fortified by The Great Wall. The geological record of Inner Mongolia has been influenced by tectonic movement and the forces of erosion, sedimentation and climate change. The fossil record of Inner Mongolia reflects several Eras dating back to the Paleozoic Era with deep-marine trace fossils from the Ordos Basin to the ancient buried forests of Wuda described as the “vegetational Pompeii” to its discoveries of dinosaurs, birds, pterosaurs, mammals and amphibians from the Jiufotang Formation, Gobi Desert, Moqi Fauna of Gezidong and Jiaxikou to more recent Paleogene mammal fossils from the Erlian Basin.
Before we explore the fossil sites it’s interesting to take a detour and understand the origins of Inner Mongolia which will help provide some context. The terms of “Inner" and "Outer" Mongolia were a historic legacy dating back to 1691 and the Manchu Conquest of China that saw the establishment the Qing dynasty. This difference at the time was based on the level of autonomy these regions had with the Qing Empire.
The collapse of the Qing Empire in 1911 saw end to the final imperial dynasty in China and the end to over two thousand years of imperial rule. The Wuchang uprising and 1912 Revolution or Xinhai Revolution led by Sun Yat-sen a former doctor come revolutionary is now regarded as the “father of modern China" and the Peoples Republic of China.
The Republic of China considered Inner Mongolia as part of China and following many years of resistance the Treaty of Kyakhta was signed in 1914 between the Chinese government and Mongolian representatives facilitated by Russia to officially recognise Mongolia. Then in 1947 following World War II the People's Republic of China moved to secure political and military control of Mongol Leaders who were disillusioned with the Mongolian government.
Today the reference to "Inner Mongolia" and "Outer Mongolia" distinguishes the independent country of Mongolia from the Inner Mongolian Autonomous Region within China.
The geology of Inner Mongolia is only part of a far larger geological complex. Asia is today the largest continent covering approximately 30% of Earth's land surface. Asia is effectively the fusing of seven ancient cratons called the Angaran, Indian, Arabian, Kontum, North China, and South China and the North Tarim craton.
Tectonic activity between these cratons has almost been continuous and is responsible for the formation of the Asian mountain ranges of the Altaids, Manchurides, Scythides, Chukotkalaskides, Tethysides, Verkhoyansk-Kolyma orogenic system and Nipponides part of the Circum-Pacific orogenic zone.
The base rock of the Inner Mongolia dates back nearly 2.1 billion years ago to the Precambrian Era known as the "Age of Early Life". At this time the Asian continent was forming, the Earth’s atmosphere was developing and early life was gradually evolving. The Precambrian rocks of Inner Mongolia are part of the North China Craton that form the bedrock of the region.
Jumping forwards to the Paleozoic Era, approximately 541 - 251.9 million years ago, Inner Mongolia was experiencing significant tectonic activity because of its proximity to the combination of divergent and convergent boundaries of the underlying cratons.
The most significant tectonic event of the time was the collision of the Siberian and North China cratons leading to Inner Mongolia becoming effectively bounded by the formation of Central Asia’s largest mountain belt known as the Central Asian Orogenic Belt or Altaid tectonic collage.
During the Paleozoic Era and specifically the Cambrian and Ordovician Periods large expanses of Inner Mongolia was submerged under shallow seas where thick layers of sedimentary rocks of limestone and shale were deposited. These marine sediments contain abundant fossils, particularly trilobites and brachiopods.
During the Mesozoic Era the region was influenced by the Yanshanian Orogeny caused by the North China Craton deforming in 3 different directions at the same time. This event led to the formation of the Yanshan Mountains and importantly the uplift and elevation of the Mongolian Plateau.
Inner Mongolia experience numerous volcanic eruptions during the Mesozoic Era depositing thick layers of volcanic ash across the landscape that would later reveal a rich biodiversity of buried fossils.
The Cenozoic Era from 66 million years ago saw Inner Mongolia experience large scale erosion, aridification and climate change. The previously uplifted mountains from the earlier orogeny’s were being eroded and their foreland basins were gradually being filled with sediment.
The regional climate changed as the prevailing winds and reduction in rainfall created the conditions for aeolian desert systems to form like the Gobi Desert, the Taklamakan Desert, and parts of the Mongolian-Manchurian steppe.
At the root of this transformative change was tectonic activity between 40 – 50 million years ago during the mountain building of the Himalayas and Tibetan Plateau. These mountain ranges played a fundamental role in creating a rain shadow by blocking moist air currents from the Indian Ocean and capturing the cool continental winds heading down from Siberia.
Today the landscape of Inner Mongolia is known for its grasslands of Hulunbuir and Xilamuren an important part of the overall Eurasian steppe region that stretches from the Great Hungarian Plains of Central Europe to Central Asia; Four of the eight Chinese deserts of the Badain Jaran Desert, Kubuqi Desert, Tengger Desert and the Ulanbuh Desert; and numerous mountain ranges.
The Great Wall
The Great Wall at 21,196km long was built over a period of 2,000 years to fortify China's northern border and is made up of from a series of walls, watchtowers and fortresses. Ironically, The Great Wall, a national symbol of China was designated an UNESCO World Heritage Site in 1987. The Great Wall roughly follows Inner Mongolia Autonomous Region southern border because it was built to protect China from foes including the Mongols.
Youtube Video of The Great Wall of China by Source: UNESCO TV / © TBS Produced
The Ordos Basin
The geology of the Ordos Basin is very old dating back to the Proterozoic Eon and extends over the Shaanxi Province and is adjacent to the Gansu, Ningxia and Shanxi provinces as well as the Inner Mongolia Autonomous Region. With a cratonised crystalline basement the basin is topped with several kilometres of younger sedimentary layers of Carboniferous, Permian, and Jurassic deposits.
Among these rock layers of the Ordos Basin are fossils of trilobites found in the Middle Ordovician Klimoli Formation from the Zhuozishan area that records ten species from four trilobite families of Raphiophoridae, Nileidae, Asaphidae, and Telephinidae.
The Ordos Basin has an abundance of trace fossils from bioturbation activities dating to the Middle Ordovician Fengfeng Formation on Mt. Jinsu located at the south-eastern margin of the Ordos basin.
The Late Triassic black shale freshwater deposits of the Yanchang Formation in the Ordos Basin are aged at between 228 – 235 million years and have fossilised chrysophyte algae that produce siliceous cysts. These fossils indicate that the Ordos Basin once had large inland lakes.
The Middle Jurassic Yan'an Formation is known for the discovery of fusain or fossil charcoal that indicates paleowildfires were common at the time.
An important Late Cretaceous fossil assemblage of vertebrates have been discovered in the Jingchuan and Luohandong formations of the Ordos Basin. Known as the “Psittacosaurus Fauna” this assemblage of fossils was named after Psittacosaurus (meaning "parrot lizard") an extinct ceratopsian dinosaur from the Early Cretaceous.
The Psittacosaurus Fauna considers approximately 1,000 track sites of saurischian footprints including the non-avian theropods of Chapus, Asianopodus and Jialingpus, the sauropod track of Brontopodus and the bird or avian theropod footprints from Tatarornipes. Dinosaur and other tetrapod footprints have also been discovered in the Luohe Formation in Xunyi County at the southern margin of Ordos Basin.
The Wuda Fossil Site
The Wuda Fossil Site was discovered in 1998 and identified as an ancient tropical coal forming rainforest buried by volcanic ash compacted between two coal seams in the Wuda Coalfield in the Haibowan District of Wuhai City.
Described as the “vegetational Pompeii” this fossil site was buried by volcanic ash leaving undisturbed high levels of preservation of many plants fossils including cycads, early conifers, progymnosperms, filicalean ferns, sphenopsids, lycopsids, seeds and insects.
The Wuda Fossil Site dates to the Cisuralian the first epoch of the Permian Period between 298.9 - 272.3 million years ago. This was a time when the Gondwanan ice sheets were melting and Earth was experiencing the Artinskian Warming Event transitioning from an icehouse into a greenhouse.
The Jehol Biota
The Jehol Biota is a terrestrial lagerstätte found across the three horizons of the Dabeigou, Yixian and Jiufotang formations located in Liaoning, Hebei and Inner Mongolia in north east of China. These horizons date from the Late Hauterivian Age to the early Aptian Age of the Early Cretaceous Epoch.
The Jehol Biota was formed in a swamp lake environment with a mix of volcanic ash layers and is known for its fossil record of Mesozoic Era seed-eating (Jeholornis & Sapeornis) and fish eating birds such as Yanornis. The Jehol Biota also holds a diverse range of exceptionally preserved fossils from a number of groups from feathered dinosaurs (Dromaeosauridae), birds, early mammals (Repenomamus), frogs, salamanders (Jeholotriton), fish (Lycoptera), pterosaurs (Jeholopterus), pollinating insects, reptiles (Yabeinosaurus), turtles, Choristodera.
The Jehol Biota also provides an insight into the Cretaceous Terrestrial Revolution when terrestrial ecosystems were reshaped by the rise of flowering plants or angiosperms around the world. Angiosperms created new habitats, food sources, and pushed the evolution of pollinating insects and plant-eating animals.
The Erlian Basin
The Erlian Basin is located on the western side of the Qinganling Mountains and whose rocks of the Nomogen, Arshanto and Irdin Manha Formation are dated to the Tertiary Period of the Cenozoic Era dating between 66 million and 2.6 million years ago.
The Erlian Basin is known for its fossil record of Perissodactyla (meaning perissos, “odd,” and daktylos, “finger) or hoofed herbivorous mammals that favoured living in warm and humid conditions and included the tapiroid and rhinocerotoids that lived alongside large pantodonts and smaller lagomorphs.
The Gobi Desert Dinosaur Fossil Sites
The vast area known as the Gobi Desert was not always a dry desert. During the Cretaceous Period this expansive desert basin had a prevailing humid climate with a landscape of freshwater lakes and rivers making it possible for a rich biodiversity of plants, animals and dinosaurs to co-exist.
Today the Gobi Desert has over 60 dinosaur fossil sites dating back to the Late Cretaceous Epoch. These fossil sites range from the wonderfully named Flaming Cliffs of Bayanzag where dinosaur eggs were discovered to Tugrugiin Shiree famous for the discovery of the “Fighting dinosaurs” of a Protoceratops and Velociraptor locked in mortal combat. The Gobi Desert was also once home to the giant carnivorous Tarbosaur a relative to the Tyrannosaurinae.
The Gobi Desert Dinosaur Fossil Sites can be located the eastern part of the desert at Bayanshiree, Khongil Tsav, Amtgai, Baishin Tsav, Urulbu khudag, Shar Tsav; in the central part are the dinosaur fossil sites of Tugrugiin Shiree, Zamiin Khond and Uuden Sair and in the western part are the dinosaur fossil sites of Ukhaa Tolgod, Nemegt, Altan Uul, Khermen Tsav, Bugiin Tsav and Guriliin Tsav..
The Baogeda Ula Fauna
The Baogedawula Formation is a sandy clay mix at between 25 – 50 meters in depth and holds the Baogeda Ula Fauna. Exposed in Zhurihe its approximately 50Km from Abagaqi Town of Xilinhot City. This formation was laid down on a once flowing river and lake system dating to the Baodean Age or equivalent middle Turolian of the Late Miocene.
The Baogedawula Formation has three fossiliferous horizons of fossil ostracods, gastropods and an abundance of large mammals including Rhinocerotidae and Giraffidae. This formation is probably more well known for the discovery of a primitive group of Hipparionine horses and namely the Hipparion tchikoicum discovered in the red clays of Tuchengzi in Huade County and Wulanhua in Siziwang Banner.
The Iren Dabasu Formation
The Iren Dabasu Formation was discovered in 1922 and exposed at Erenhot in the Iren Nor region of Inner Mongolia. It was formed by a flowing braided river dating to the Late Cretaceous Epoch whose heavily vegetated floodplain not only is a shell bed but also a dinosaur bonebed accumulating dinosaur skeletons, bones and nests of dinosaur eggs.
This was once the home to a diverse dinosaur fauna including the carnivorous tyrannosauroid of the Alectrosaurus, the gigantic caenagnathid Gigantoraptor erlianensis and the large herbivorous Hadrosaurid of Gilmoreosaurus and smaller bird like Troodontidae.
The Gezidong and Jiaxikou Fossil Sites
The freshwater fossil sites of Gezidong and Jiaxikou are near to Baoshan Town in eastern Inner Mongolia and date back to between 119.20 -118.67 million years ago during the Early Cretaceous Epoch.
Known as the Moqi fossil bed or Moqi Fauna its an exceptionally preserved conservation Lagerstätte rich in vertebrates of salamanders (Nouminerpeton), frogs (Genibatrachus), turtles, fish (Peipiaosteus), lizards, birds (Khinganornis), insects, dinosaurs and conchostracans (Eosestheria & Ephemeropsis).
Before Travelling to Inner Mongolia
Remember, Inner Mongolia is effectively a province of China while Mongolia is separate country. For people travelling on a full “British Citizen” passport from the UK please follow UK government’s travel checklist to understand and advice before travelling to Inner Mongolia on the current rules for the most common types of travel.