Since the initial discovery of dinosaur fossils in 1915 and following a major exploratory dig of the Dashanpu Dinosaur Fossil Site covering an area of over 70,000 square meters between 1972 – 1977. The scale and importance of these fossils became nationally recognised by the Chinese Government and the excavations less than 10 Km east of Zigong City in the District of Da'an within the Sichuan Province the second largest province in the south west of China became one of the country's first national parks. By May 2017 the fossil site was internationally inscribed as the Zigong UNESCO Global Geopark along with the Zigong Dinosaur Museum. This City Zigong has a built a reputation over many years as the, “Millennium Salt City”, “South City of Lanterns”, “Delicacy Home” and now the “Hometown of Dinosaurs” with over 200 specimens of sauropods, theropods, basal Neornithischia, stegosaurs, as well as fish, amphibians, turtles, crocodiles, pterosaurs and therapsids unearthed and on display.
Travelling to Zigong means a choice of planes, trains or automobiles or all three. Zigong is serviced by the airports of Chengdu International Airport, Chongqing International Airport, Yibin Airport and Luzhou Airport though these are all several hours drive away.
Zigong lays within the Sichuan Basin also known as the Red Basin. Formed on the Upper Yangtze block one of the two including the Cathaysia block that forms the basal rocks of South China.
The Sichuan Basin is surrounded by mountains and is renowned for its substantial oil and gas reserves found within failed rift zone's known as aulacogen or concealed sags or depressions. This area of South China is generally accepted to have been located at one time along the northern periphery of East Gondwana.
This part of Asia has been tectonically active for a very long time having experienced the outcome of mountain building events dating back to the Jinning Orogeny during the late Middle Proterozoic era roughly 830–720 million years ago through to the Caledonian Orogeny, Variscan Orogeny, Indosinian Orogeny, Yanshanian Movement and the rise of the Himalayas some 50 - 60 million years ago.
The Sichuan Basin is a foreland basin to these mountains and is bordered by a complex of tectonics and deep-large faults. The Sichuan Basin has experienced an almost continuous succession of terrestrial sedimentation from eroding mountains into rivers, streams, lakes and delta's as well as once being influenced by the formation of a mega-lake in the Sichuan Basin known as the Ancient Bashu Lake during the Late Mesozoic.
The depositional environment and geological setting of the area around Zigong has meant that an almost continuous series of Mesozoic Era formations dating from the Lower Triassic Jialingjiang Formation and important oil and gas reservoir to the fossiliferous Upper Jurassic Suining Formation and Penglaizhen Formation to the Upper Cretaceous Sanhe Formation.
The Dashanpu Dinosaur Fossil Site captures a snap shot of the Middle Jurassic Epoch between 174 - 163 million years ago in the Xintiangou Formation and Shaximiao Formations with its notable Shunosaurus Fauna. This was a diverse and rich and biodiverse ecosystem for dinosaurs to exist and for their remains to be fossilised.
During this time the Earth was experiencing fluctuations between arid and humid climates, global-scale warming, sea level rise, and significant cooling events, including the Callovian Ice Age lasting about 2.6 million years affected mainly marine environments though ice sheets may have developed over the high-latitude mountainous regions in the northern latitudes.
Though the primary excavation of dinosaurs was from the Lower Shaximiao Formation near to the City of Zigong further exploratory work at the Yunyang dinosaur locality in Laojun Village in north-eastern Chongqing has established that the 14 fossil-bearing layers of lake and river deposits of the Xintiangou Formation and the Lower and Upper Shaximiao Formations contains the most abundant source for dinosaur fossils in the Sichuan Basin.
What makes these discoveries different is the appearance of bony tail clubs in sauropods and the possibility of the earliest record of stegosaurs in Asia called Bashanosaurus primitivus. Our traditional image of a stegosaur is having of two rows of armoured plates running down the the left and right side of its back extending from the neck to tail.
In this species there are a number of distinctive features or autapomorphies that are uniquely specific including the emergence of externally visible dorsal vertebrae on its back and protruding spines from the shoulders as amour. This species is also a close relative to Chungkingosaurus and Huayangosaurus other stegosaur found nearby and these species are collectively considered some of the earliest stegosaurs known to have evolved in Asia and possibly globally.
From Left to Right:
Example of a Shunasaurus (Image by Daderot) | I Example of a Huayangosaurus (Image by Giloun) |
Example of a Chungkingosaurus (Image by Laikayiu)
The other notable dinosaur discovered is the herbivorous Shunosaurus. A medium-sized sauropod that grew to around 9 meters in length and smaller by comparison to the giant Dashanpusaurus measuring in at over 15 meters in length and had a long neck, four sturdy limbs and a relatively lightweight body.
By comparison Shunosaurus had a compact body and short neck with sturdy limbs to support its weight. Unlike other sauropods, Shunosaurus had a unique weapon – a club-like tail tip that may have been used as defensive weapon to ward off predators rather than relying on its size alone for protection.
Agilisaurus (meaning “Agile Lizard”) was a small and nimble plant eating ornithopod dinosaur measuring about 1.2 meters in length. Its lightweight and agile body made it well-suited for running about on two legs through dense vegetation.
The Dashanpu Dinosaur Fossil Site in the Sichuan Province of China offers the traveller a remarkable glimpse into the prehistoric world of the Middle to Late Jurassic period and is worthy for an off the beaten track adventure to experience this country's fossil richness.
Before Travelling to China
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 China on the current rules for the most common types of travel. Travelling to Zigong means a choice of planes, trains or automobiles. Zigong is serviced by the airports of Chengdu International Airport, Chongqing International Airport, Yibin Airport and Luzhou Airport though these are several hours drive away.
Commenti