Wudalianchi Scenic Spots

Description

The Wudalianchi is one of the first batch of state scenic spots areas approved though the State Council in 1982, and a state-level nature reserve approved in 1996. There are the most typical and perfect vestiges of modern volcanic eruption in China, and the world- known volcano-related mineral spring water. The Wudalianchi volcanic cluster is situated in the E-W tectonic belt at the junction between Xiaohinggan Mts. Uplift and Song-Nen depression. The volanic eruption was related to the faulting activity between the above-mentioned two tectonic units. One of the major sets of fault trends 42 NE,i.e. the Cathaysian lineament, which controls the direction of volcanoes; the other set of fault trends NW-SE, intersecting the former at an angle about 90 ,where the basic lava erupted through their intersections to the surface to give rise to volcanoes. There are totally 14 volcanic cones of the Wudalianchi volcanic cluster, which are distributed mainly along NE direction as two volcanic chains, with the exception of the S. Gelaqiu Mt. and N. Gelaqiu Mt. on the westewnmost place. The volcanic cluster is a product of the repeated volcanic eruptions since the Pleistocene of Quaternary, giving rist to the rocks of volcanic cones and lava flow, all belonging to K-rich alkali basalt. The Laohei Mt. and Huoshao Mt. in the central part were confirmed to have been formed through eruptions in AD 1719-1721, according to the record in the ?Anecdotes on Heilongjiang ? and ?A brief of Ningguta ? in Qing Dynasty. With rocks fresh and lava landforms preserved almost intact, these volcanoes are called new-stage volcanoes; whereas the rest 12 volcanic cones on the periphery and the lava platform around them, which were formed earlier and experienced long-term weathering, are the product of prehistorical eruptions and are called the old-state volcanones. All the 14 volcanic cones, regardless of their age and size, belong to detrital cones, i. e. They were formed of lava fragments e. G. Volcanic bombs, driblets, scria, pumice and lapilli which were thrown out from the vents to the air fell on the ground. Through repeated and intermittent eruptions and layer ?by-layer accumulations, volcanic cones with strata dipping outward were thus formed, which are intermediate degree of explosion and short periods of eruption, belonging to the Strombolian-type of Mediterranean. The vestiges of old-state volcanones are mostly covered under regoliths due to the long-term weathring, and there are only those of new stage, the Laohei and Huoshao Mts., with the age less than 300 years since the eruption, have the volcanic apparatures and the forms of volcanic cones, lava flow and volcanic fragments well-greserved and the major vestiges to be protected in the nature reserve. Their descriptions are given as follows: Vestiges of volcanic cones The laohei Mt. wes formed through the eruptions in 1719-1721. It gained its name (Laihei =old black in Chinese ) owing to the cover of black volcaniclasts on its southern slope. The eruption can divided clearly into two stages. The first state was dominated by eruption of volcanic fragments, and was the very period of the formation of volcanic cone.The second state, by the effusion of lava, when the lava undercut the fractures in the lower partt of cone and f;ew outward. Up till now, two openings for the outlet of lava are still preserved on the northern shope of the cone, and there are tunnels formed after the flo9w of lava. The crater appears in a funnel shape, 350m in diameter, 140m in depth, with steep inside wall. The volcanic neck is coverd by later talus. The volcanic neck is covered by later talus. The volcanic cone is surrounded by spilled-out lava, with a series of small parasite cones spread therein. The Huoshao Mt. had its eruption age and process roughly the same as that of the Laohei Mt. , but the cone is much lower and the crater appear as an oval shape with an N-S macro-axis. The rim of the crater is uneven, with two U-shape gaps on northern and southern sides, which were the positions where the lava was spilled out; and there are protrusions on eastern and western western sides, resulting in the name ?two-half mountains?. On the cone slope there are volcanic bombs of various shape. The lava flew mostly the northern gap, giving rise to a gigantic laca fan. The crater has a relatively flat bottom, with a small scoria cone protruding in the middle and ten odd small explosive pits formed from the local release of gas within the lava. Vestiges of lava flow The lava flow which effused out from Laohei and huoshao Mts. Is exposed on the surface 65km2 in area . The various characteristic shapes and primary structural features appear vividly as if they are frash. The field survey has revealed at least two large-scale effusions. The lava flooded along the old chnnel of Baihe river, giving rise to an elongated lava flow mass, resebling a black-colored dragon creeping on the ground, which is called by local people ?stone dragon?. Being comparable to many other basic lava volcanoes abroad,the lava here appears as two types differing utterly from each other with respect either to shape and to structure, i.e. pahoehoe and aa lavas. The pahoehoe lava, having generally a flat and smooth surface, is the surficial layer of lava whivh solidified earlist in ots flowing process. It has been notably broken, and the cooled surficial crust may have been sometimes plastically deformed when the liquid lava beneath it continued to flow, leaving vaious surficial structural featres, which the common ones are: 1) ropy lava, resulting from curling and torsion of the lava crust; the ?ropes? are mostly bent in arcuate from with the apex of arc pointing to flow direction; 2) wavy lava, with the surface folded into wavy form; 3) bun-like lava, with the ?buns? resulting from from the expansion of gas escaping from the liquid lava beneath the crust; 4) creeping worm-like lava, branches of lava which flew out along slopes at the margin of lava flow mass, with features like lava fall, elephant trunk etc. Reflecting the form of flow at that time. There are still other features like lava tunnel, lava stalactite, lava stalactite, lava outflow dome etc. Which are not to be described in detail here. Aa lava , also called clinkerky or slaggy lava, is composed o9f various-sized blocks and fragments resuting from the brittely or semi-plastically broken lava crust solidified earlier in the process of lava flow. Field observartion has found that the pahoehoe often occurs near the volcanic vent, which grades through a certaigh a certain distance into aa lava. On the rugged surface of the aa ?sea?, there are occasionally blocks in the shape of bear, ape, ox etc. But the strangest feature of all is groups of gas exhalation cones, hundreds in number, standing on the vast aa surfaca on both sides of the 4 th and 5 th Pools (lakes) respectively on eastern piedmont and northwest o9f Huoshao Mt., Their formation was due to intermittent escape of gas carrying some lava throuth the solidified or semi-solidified lava which flew to the swampy zone when the liquid lava in the lower part became vapor-rich, and the cones were thus formed from the layer-by-layer accumulation of lava around the vents. The exhalation cones have multifarious shapes like tower, cone, mound etc., being always hollow inside, with usually an opening on top, which is rarely closed. The inside well of the hollow cone is full of lava stalactites hanging downward resuting from the falling of liqid lava, constituting a marvellous picture. Most of the coneds stand upright, but there are also someones slanting or flat-lying, and someones are brolen in two from top to bottom. These phenomena, though not common, suggest a continued flow of lava during or even after the process of the formation of cones. Accompanying the exhalation cones there are exhalation discs which are the embryonic form of exhalation cones, with only much less times of intermittent liquid eruption, generally consisting of only two to three layers of driblets. If the Wudalianchi is said to be a museum of volcanic geoogy, these exhalation cones and discs are the outstanding ?exhibits?which are rarely seen either at home or abroad regarding to their beautiful apearance, their large number and their wide distributtion. Vestige of volcanic fragments The lava erupted from the Wudelianchi volcanoes belongs to basic magma with high temperature, low viscosity and high fiuidity. The eruption was dominated by quiescent effusion, with only explosion in the beginning , when large quantity of gas released blew up the liquid lava or solid rock blocks into the air, which fell on the ground to give rise to volcaniclastic ejecta and are distributed mainly around the crater to make up the volcanic cone. The volcanic fragments are classified according to their shape, structure and state of substance into volcanic bomb, driblet, scoria, pumice block and lapilli,of which the volcanic bombs scattered on slope of and around the volcanic cone are most noticeable in their multifarious shapes, e.g. spheroidal, ellipsoidal,fusiform, belt-like, twisted, ring-like etc..Bombs including cores of granite are also commonly seen. Besides the above-mentioned vestges of volcanic geology, the volcano-related mineral spring water is also a wonder of Wudalianchi which is one of the three major cold mineral springs in the world. It is a ferrosiliceous Mg-Ca bicarbonate type low teperature mineral spring, characterized by large reserves, strong capability of regenration, high degree of mineralization at low temperature, compatibility of mineral substance with the needs of human body ,suitabilityfor both drinking and bathing, nonpoisonousness and harmlessness. The testing using the most advanced measures by the Water Quality Research Centre of the Research Institute of Water Power, Ministry of Water Conservancy and Electrical Power and Chinese Academy of Sciences has shown that the mineral spring water contains 30 odd elements indispensable to humean body and belongs to precious volcanic mineral spring water and the best composite spring water for medical use both at home and abroad. The practice of recuperation for more than 100 years has shown that the mineral spring water of Wudalianchi can cure more that 100 kinds of disease, especially for some chronic and stubborn diseases in digetive, nervous and circulatory sysems and on skin which can hardly be effectively cured by drugs. It is widely praised as a holy spring water which can ?cure your illness when your are ill, and make you healthy and prilong your life when your are not ill?. Sun Changren, Vice-directorand Secretary-general of the China?s Special Committee on Mineral Spring Water said :?any other mineral spring water in China cannot compare with that of Wudalianchi?. Ms Yue-sai KAN , A Chinese of US citizenship, said ,? the mineral spring water has brought us a miraculous surprise beyond metaphor?. There are five mineral spring water belts found in Wudalianchi: 1) bicarbonate water of Yao quan Mt. belt; 2) ferrosiliceous bicarbonate water of E. Jiaodebu Mt. belt; 3) carbonic acid water of Weishan Mt. belt; 4) carbonic acid water of Huoshao Mt. belt; and 5) metasilicic acid-radon water of Baolong Spring belt.