Ha long bay popular travel destination
Ha Long Bay has an area of around 1,553 km2, including 1,960–2,000 islets, most of which are limestone. The core of the bay has an area of 334 km2 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 consists of a dense cluster of some 1,600 limestone monolithic islands each topped with thick jungle vegetation, rising spectacularly from the ocean. Several of the islands are hollow, with enormous caves. Hang Đầu Gỗ (Wooden stakes cave) is the largest grotto in the Hạ Long area. French tourists visited in the late 19th century, and named the cave Grotte des Merveilles. Its three large chambers contain large numerous stalactites and stalagmites (as well as 19th century French graffiti). There are two bigger islands, Tuần Châu and Cát Bà, that have permanent inhabitants, as well as tourist facilities including hotels and beaches. There are a number of beautiful beaches on the smaller islands.
A community of around 1,600 people live on Ha Long Bay in four fishing villages: Cửa Vạn, Ba Hang, Cống Tàu and Vông Viêng in Hùng Thắng commune, Ha Long city. They live on floating houses and are sustained through fishing and marine aquaculture (cultivating marine biota), plying the shallow waters for 200 species of fish and 450 different kinds of mollusks. Many of the islands have acquired their names as a result of interpretation of their unusual shapes. Such names include Voi Islet (elephant), Ga Choi Islet (fighting cock), Khi Islet (monkey), and Mai Nha Islet (roof). 989 of the islands have been given names. Birds and animals including bantams,antelopes, monkeys, and lizard also live on some of the islands.
Almost all these islands are as individual towers in a classic fenglin landscape with heights from 50m to 100m, and height/width ratios of up to about six.
Another specific feature of Halong Bay is the abundance of lakes inside the limestone islands. For example, Dau Be island has six enclosed lakes. All these island lakes occupy drowned dolines within fengcong karst.
In 2000, the UNESCO’s World Heritage Committee has inscribed the Ha Long Bay in the World Heritage List according to its outstanding examples representing major stages of the Earth’s history and its original limestone karstic geomorphologic features. The Hạ Long Bay and its adjacent areas consist of a part of the Sino-Vietnamese composite terrane having its development history from pre-Cambrian up to present day. During Phanerozoic, terrigenous, volcanogenic and cherty-carbonate sediments containing in abundance graptolites, brachiopods, fishes, corals, foraminiferas, radiolarias, bivalves and flora, separated one from another by 10 stratigraphic gaps, but the boundary between Devonian and Carboniferous has been considered as continuous. The limestone karstic geomorphology of the bay was developed since Miocene, especially the cone-shaped hills (fengcong), or isolated high limestone karst towers (fenglin) with many remnants of old phreatic caves, old karstic foot caves, marine notch caves form magnificent limestone karst landforms as unique on the world. The Quaternary geology was developed through 5 cycles with the intercalation of marine and continental environments. The present Ha Long Bay, in fact, appeared after the Middle Holocene maximum transgression, leaving ultimate zone of lateral undercutting in the limestone cliffs bearing many shells of oysters, having the 14C age as 2280 to >40,000 y. BP. Geological resources are abundant: anthracite, lignite, oil shale, petroleum, phosphate, limestone and cement additives, kaolin, silica sand, dolomite, quartzite of exogenous origin, and antimony, mercury of hydrothermal origin. Besides, there still are surface water, groundwater and thermal mineral water on the shore of the Hạ Long - Bái Tử Long Bays and other environmental resources.
In terms of marine geology, this area is recorded as an especially coastal sedimentary environment. In the alkaline seawater environment, the chemical denudation process of calcium carbonate proceeds rapidly, creating wide, strangely shaped marine notches.
The bottom surface sediments are various from clay mud to sand, however, silty mud and clay mud are dominated in distribution. Especially, the carbonate materials originated from organisms make up from 60-65% sedimentary content. The surface sediments of coral reefs are mainly sand and pebbles of which the carbonate materials occupy for more than 90%. The intertidal zone sediments are various from clay mud to sand and gravel depending to distinguished sedimentary environments such as mangrove marshes, tidal flats, beaches etc. At the small beaches, but wonderfully beautiful, the sand sediments may be dominated quartz or carbonate materials.
The sediment layers of intertidal zone, the upper sea bed with a plain surface conserving ancient rivers, systems of caves and it's sediments, traces of ancient marine action forming distinctive notches, beaches and marine terraces, mangrove swamps are important evidence of geological events and processes taking place during Quaternary.
phongnhabackpackerhostels.com (phongnhabackpackerhostels.com Blog)