Ha Long Bay is a UNESCO World Heritage Site and popular travel destination in Quang Ninh Province, Vietnam. The name Hạ Long means "descending dragon". Administratively, the bay belongs to Ha Long City, Cam Pha City, and is a part of Van Don District. The bay features thousands of limestone karsts and isles in various shapes and sizes. Ha Long Bay is a center of a larger zone which includes Bai Tu Long Bay to the northeast, and Cat Ba Islandto the southwest. These larger zones share a similar geological, geographical, geomorphological, climate, and cultural characters.
Ha Long Bay has an area of around 1,553 km2 (600 sq mi), including 1,960–2,000 islets, most of which are limestone. The core of the bay has an area of 334 km2 (129 sq mi) with a high density of 775 islets.The limestone in this bay has gone through 500 million years of formation in different conditions and environments. The evolution of the karst in this bay has taken 20 million years under the impact of the tropical wet climate. The geo-diversity of the environment in the area has created biodiversity, including a tropical evergreenbiosystem, oceanic and sea shore biosystem. Ha Long Bay is home to 14 endemic floral species and 60 endemic faunal species.
Ha Long Bay is located in northeastern Vietnam, from E106°55' to E107°37' and from N20°43' to N21°09'. The bay stretches from Quang Yen town, past Ha Long city, Cam Pha city town to Van Don district, bordered on the south and southeast by Lan Ha Bay, on the north by Ha Long city, and on the west by Bai Tu Long Bay. The bay has a 120-kilometre-long (75 mi) coastline and is approximately 1,553 km2 (600 sq mi) in size with about 2,000 islets. The area designated by UNESCO as the World Natural Heritage Site incorporates 434 km2 (168 sq mi) with 775 islets, of which the core zone is delimited by 69 points: Dau Go island on the west, Ba Ham lake on the south and Cong Tay island on the east. The protected area is from the Cái Dăm petrol store to Quang Hanh ward, Cam Pha city and the surrounding zone.
Ha Long Bay has experienced at least 500 million years in various geological states of orogeny, marine transgression and marine regression. During the Ordovician and Silurianperiods (500-410 million years ago), Ha Long Bay was deep sea. During the Carboniferous and Permian periods (340-250 million years ago), Ha Long Bay was at shallow sea level.
The dominated uplift movement of neotectonic and recent tectonic influenced deeply on topography of this area, and the present landscape of sea-islands was formed around 7 or 8 thousand years ago by the sea invasion during Holocene transgression begun at about 17-18 thousand years ago. Particularly from the Holocene time, from about 11,000 years ago Cat Ba - Ha Long area has much archaeological evidence connecting variations in sea levels with the development of ancient cultures such as the Soi Nhu and Ha Long cultures.
Karst geomorphology value
Due to a simultaneous combination of ideal factors such as thick, pale, grey, and strong limestone layers, which are formed by fine-grained materials; hot and moist climate and slow tectonic process as a whole; Ha Long Bay has had a complete karst evolution for 20 million years. There are many types of karst topography in the bay, such as karst field.