Ha Long Bay's modern birth was the result of evolution long-term geological synthesis of many elements of events, including most notably the formation of thick layers of limestone on the 1000 m at the age of bon - Permian (340-240 million years ago), the formation of Ha Long basin in Neogen century (26 to 10 million years ago). Formation process Caxto plain limestone most active on Pleixtoxen Quaternary (2 million - 11,000 years) and the sea in the era Holoxen.
Thus, visitors to Ha Long Bay is not only to the "wonders" of the world but also to a precious geological museum maintained outdoors to 300 million years. The cave is not only the castle but also the creation of vivid evidence of the erosion of the sea through the geological record.
In the early Cambrian (570-500 million years ago), Halong Bay is basically the floating continent high, subject to the leaching process of denudation. By the end of the Cambrian area was engulfed, from which new Halong Bay.
During the century and Silua Odovic (500-400 million years ago), Halong area and northeast U.S. base is located in the deep sea operation mode active site trough, the sea floor is lowered at constant , at the deposition of sedimentary strata in the Co structure phrasing over 2000 m thick containing many fossil stone pens.
At the end of Silua century, this area is undergoing phase inversion motion painting created seas turn into folded mountains. Since the end of the century Silua and De-volts (420 to 340 million years ago), Halong Bay area is a mountainous region under the strong denudation erosion in dry conditions, Ha Long is part of the continent Katania large to cover almost the entire South China Sea and Chinese continental shelf today.
At the end of De-century capital, due to the effects of tectonic movements Haxini, Ha Long area and the Northeast were raised and the marine environment completely disappeared. Shares stage late onset (age of carbon and PEC mi) extending from 340 to 240 million years ago, a warm shallow sea mode is set back to century-long carbon and most of the Permian.
Mode shallow sea that existed hundreds of millions of years have accumulated should form limestone origin and biological chemistry with Cat Ba layer early age carbon layer thickness 450 m and the Quang Hanh old high carbon , Early Permian 750 m thick, two-tier system is dominated absolutely on hundreds of islands of Halong Bay.
To the whole college freshmen (67 million years ago), Halong Bay existed in continental alpine environment under the influence of the phase to create a strong painting. Paleogen half, and gradually increase motion and stability, erosion process started strong. After a period of denudation millions of years, a form of semi-plateau terrain formation, strong erosion process was gradually divided into the array surface elevation corresponding to the peak now.
To the Quaternary, especially since the mid-century Neogen, Caxto erosion process dissolves limestone strong development in karst of Cruises in Halong bay. The limestone islands in the bay today, is essentially the mountains on the surface of the plain error Caxto been doing marine submerged Holoxen century. Pleixtoxen time period is mainly created systems known caves in Ha Long Bay, they are often concentrated in the high 10 or 15; 20, 25 and 60 m.
Initially, rain water flowing in the cracks of the limestone breaks are created by tectonic movements arising faulting. Chemical corrosion caused by rainwater expanding gaps cracks to form caves. The cave is popular with middle and late age of about Pleixtoxen (70,000 to 11,000 years ago) because by around 2 to 3 thousand years ago the sea had entered the area of Ha Long and Ha Long Bay form the ancient times.
Holoxen period, from 11,000 to 7,000 years ago, sea level rise is faster than remote but still Halong mainland. From 7000 to 4000 years ago, marine Holoxen maximum extension and Ha Long Bay officially formed.
Last 4000 - 3000 years ago, the sea back to the period of this region appeared Ha Long culture. In the early Holoxen late, raising sea again, to re-create on the Ha Long Bay marsh creeks, but narrower than before. Create the waterline on a cliff today. In the mid-late Holoxen, Ha Long Bay persisted but narrowed again.
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