Geological environment of the tienyen – hacoi bay tuyển tập tài nguyên và môi trường biển, tập 10, tr 54 66 NXB khoa học và kỹ thuật

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NAM HQC· " TUYENTAP ONMLKJIHGFEDCBA cbaZYXWVUTSRQPONMLKJIHGFEDCBA TArNG'UYEN "' A .•• ~ VA MOl TRUONG BIEN T~PX B a n b ie n t~ p : T ru d n g P G S , T S N guyen ban: 'I'h tr k y : V an T i~ n T S N g u y en H uy Y ~t T S N guyen D ue C u T S N guyen H uu C li C a c tb a n h v ie rn T S L uu V an D i~ u T S T rlln D ue T h~ nh T S D b C ong T M N H A X U A T B A N K H O A H Q C vA lIT T H U A T H A N or - 2003 T , N H ;, r e s u lt s of ± % , ,C d , MVC Ll)C A s, ± T ran g - L ei n i d fiu k d e s ig n , n arn h o at d o n g v a p h at tri~ n cu a P h an v ien H d u o n g h C tai H P h o n g (1 9 - 0 ) ~ Q A /Q C N g u y in la r e h ig h t C o astal E ro sio n an d S ed im en tatio n V a n T ie n in V ietn am 20 T r a n D u e T h a n h , P h a m H u y T ie n , B ui H ong Long, N guyen V an C u R esearch es in E stu arin e E n v iro n m en t O v erv iew o n A ctiv ities an d R esu lts an d E co sy stem o f R ed R iv er: A n 34 T r a n D u e T h a n h cbaZYXWVUTSRQPONM G eo lo g ical E n v iro n m en t o f th e T ien y en - H aco i B ay 54 N guyen H uu C u, N guyen N goe, T ran D ue T hanh, D in h V a n H u y , N g u y e n Q u a n g T u a n , N guyen V u Tuan, N guyen Thi P huong H oa, N g u y e n T h i K im A n h , D a n g H o a i N h o n S tu d ies o n S eaw eed s in V ietn am 67 N g u y e n V a n T ie n , N g u y e n H u u D a i R esearch es in D istrib u tio n o f V ietn am ese S eag rasses 76 N g u y e n V a n T ie n C au tru e v a tie'n h o a d ia ch at v u n g b b i y en b i~ n N g h ia H u n g N g u y e n H iiu C ll, T r titi D u e T h a n h , N g u y e n Q u a n g T u r in , D iin g N g u y in N g u y in T h i K im A n h , B u i 89 va T u r in , Hoai Nhan, V a n Yumig D ac tru n g h in h th - d o n g lu c v a b ien d an g b o H H au , N am D in h Dinh 106 V a n H u y , D D in h C h ie n , T r iin D u e T h a n h , B u i V a n V z i< ;J n g M o t su u t?-p h o a th ach tru n g 16 ( F o r a m i n i f e r a ) M io x en m u o n it d u o c b iet d e'n ONMLKJIHGFEDCBA d k h u Y I;iCb n tram tich D ~ tam y en b i~ n D n g H d i (Q u an g B in h ) N g u y in N g o c , N g u y in Hiiu 126 C ll B u d c d fiu d an h g ia tac d o n g cu a h H o a B in h d i v d i n g u o n lei ca b i~ n y en b o 139 T r t i n D u e T h C J - n hD, D i n h C h i e n 1 K h a n an g tac d e)n g cu a m o t so ' h in h th irc n u o i th u y san d e'n m i tru o n g v u n g b i~ n y en b o H P h o n g 161 L u u V a n D ie u , H ien tran g , x u th e' b ien d i m o i tru o n g d ia h o a tram tich d fim n u i t~ i 171 v u n g y en b i~ n H P h o n g N g u y in Thi Thu nu« N g u y in M o t so ' d § n lieu v g an h h u o n g cu a cac m uoi d in h d u d n g ( P v d i m at d e) te' b ao q u an x ii th u c v at p h u d u tai v in h H ~ L o n g N g u y in T h i M i n h Huyen, C h u V a n T h u o c , D ue C u -, N O ;) d i va Thi Luu 182 349 Tuyln tgp TaiRQPONMLKJIHGFEDCBA n g u y e n va M6i t r u a n g bien TgpNMLKJIHGFEDCBA x GEOLOGICAL ENVIRONMENT OF THE TIENYEN - HACOI BAY Nguyen Huu Cu, Nguyen Ngoe, Tran Due Thanh, Dinh Van Huy, Nguyen Quang Tuan, Nguyen Va Tuan, Nguyen Thi Phuong Hoa, Nguyen Thi Kim Anh, Dang Hoai Nhon IN T R O D U C T IO N The Tienyen administered in area ponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA - Hacoi Bay, located by the Quangninh The bay Northeastward in the Northeast of Vietnam Province, is over 50 km long and some 400 sq.km is impounded by a range of big islands, order, the Caibau, Vanvuoc, Vanmuc, Caichien, which are, Bovang, Tieu, Dai and Dautan of Tiencen and Hacoi functioning bay The bay is rich in natural the It is a large coastal ~ody of water ?y the mixture of the sea and rivers from the northwest, two typical estuaries in and Vinhphuc Islands, and connected with the sea through inlets of Mo (northeastwards Cai Bau Island), and which form the as sub - systems of the resoures, both biotic and abiotic, on which about 227,660 people (22.3% of the Quang Ninh population total in 2000) from the five districts of Vandon, Tienyen, Damha, Haiha and Mongcai are living In an endeavour to orient a sustainable use approach of the bay, purposes of the paper are (1) - to specify geological environment and (2) - to devise proposals of sustainable characteristics of the bay use based on the obove characteristics The paper has been completed by the Natural Science Council's support in 2003 M E T H O D S A N D M A T E R IA L S The Tienyen - Hacoi bay is considered as a-coastal structural 54 components, among which is an geosystem containing accumulative basin Integrative T u y ln approaches to the nature environment methods v a M6i Tai nguyen tr u a n g of the bay by recording its characteristics and identifying of research tg p problems of environmental Materials T iip x of geological geology are the main used to complete the paper results of surveying physical conditions and natural bien are mainly from resources of the bay during the years 2002 - 2003 in the NeST project conducted by the HIO GEOLOGICAL ENVIRONMENT STRUCTURE 3.1 Basement Rocks 1 C r y s ta lin e R ocks The crystaline rocks porphyritic granodiorite, are composed of porphyritic granite, granophyre, aplite, and aplitic granite aged middle Trias of the Nui Dieng complex, exposed in the northwest of the bay, Jurassic fine - grained biotite granite and aplite of the Pia Oac complex, km north of the bay S e d im e n ta r y R ocks The sedimentary basement sandstone, tuffaceous sandstone, siltstone with a thickness and chert shale, rocks include late Ordovician - Silurian sericite - quartz schist, tuffaceous gristone and of 900 - 1,000m and banded siltstone, phyllite, sericite schist and tuffaceous claystone, clay sandstone thickness of 700m of the Tanmai formation, just a few kilometres southeast quartz with a northwest and of the bay The Tanmai formation is covered with Devonian rocks of the Songcau group (conglomerate, shale and limestone), gritstone, quartz sandstone, clay and chert 1,150 - 1,390m thick in the southeast, the Duongdong formation (quartz sandstone, siltstone, clay and chert shale), 1,000 - 1,300m thick in the southeast, the Banpap formation (clayist limestone, limestone and chert), 650m thick in the south, with Triassic rocks of the Binhlieu formation (tuffaceous siltstone, sandstone, tuffogenous conglomerate and gritstone of the lower subformation, 500 - 600m thick, rhyolite, dacite, shale and tuffaceous sandstone of the upper subformation, formation shale 800 - 1,OOOmthick) in the northeast, (coal seams conglomerate, of the lower subformation, gritstone, 1,500 quartz - 1,700m conglomerate and sandstone of the upper subformation, southeast of the sedimentary Jurassic The upper rocks of the conglomerate gritstone, part Hacoi formation quartz sandstone, sandstone, thick, siltstone siltstone siltstone, and quartz 600 - 700m thick) in the rock basement exposed the Hongai around the is composed of bay, which are or clay shale of the lower 55 RQPONMLKJ T u y in tij,p T a ; n g u y e n subformation, v a M i tr u o n g 300 - 750m thick, subforrnation with a thickness C o v e r in g b iin T i j , p mlkjihgfedcbaZYXWVUTSRQPONMLKJIHG X sandstone, siltstone and shale of 700 - 800m [8 - 11].NMLKJIHGFEDCBA D e p o s its Besides the weathering crust on the basement rocks exposed around the bay, the surfacial deposits are composed of unconsolidated manifested of the upper along the northwest basin These sediments Quaternary shore of the bay and bottom sediments sediments in the are as follows: - Midle - late Pleistocene and clay with a thickness - Late Pleistocene aluvial - proluvial (Qll,lll)o f pebble, boulder, sand of - 6m marine sediments (m QIll)of sand, clay and fine pebble with a thickness of - 8m - Early - midle Holocene marine sediments pebble with a thickness (m Qr/,2) of sand, clay and fine of - 4m - Late Holocene boggy and marine sediments (bm Q JV 3) of sand, silt and clay with a thickness of - 2m [8 - 11] - Bottom sediments aleurites and aleuritic 3 S u r f a c ia l Based include gravels, pebbles, medium and fine sand, coarse - pelitic mud [4, 14] S tr u c tu r e on the geological environment dynamics of geological processes products, the (GE) of the region can be divided into the following units (fig 1) [4] : (1) - Coastal G E system (La) - Coastal marine GE type (Lb) - Coastal water body (bay) GE type - Inlet G E subtype - Basin G E subtype - Tidal flat GE subtype High tidal flat form Low tidal flat form (Lc) - Island G E type RQPONMLKJIHGFEDCBA 56 "and its 1)0'RQPONMLKJIHGFEDCBA \0,'1 M JJ: l.a YJ ponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFED I06"'lrst U' ", 30' CHINA I LEG EN D , .-: , -j!!jjf\ , - c ~~o;;;'Cal' ~ • •• 1234567 1lO' t-C castal m arine G E type, 2· lnlet G E subtype, • Basin G E 5utype, • Tidal flat G E subtype: hlgh/Jow ,5· lsland G E type, 6-C oastallow G E typo, 7- H ili and m ountain land G E type ~ ~) • ~) ~ -s ~, • ~ ~ ~) ;:s c:: ~, Scale - 1: 200 000 Okm ~ • • "1 ;: ~, " I ~.iii···::""" ' ' '.', { - r , '.' ' '/.';(T"j '0' 1 - I ,c r II,,· 11 1IIII1 I NMLKJIHGFEDCBA ,., 10' Iori · ;:s ()Q 0- • ~) ;:s< ~ ~ ~) F ig u r e 01 -l Geological environment structure of Tienyen Hacoi Bay region >< T u y ln tg p Tai nguyen va M6i tr uang bien Tgp x (2) - Land GE system (2a) - Coastal low land GE type (2b) - Hill and mountain GE type The coastal marine GE type of the region is located southeast of the frontal islands down to some 10m deep, where the bottom is covered mainly with coarse aleurite in a dynamic condition of seasonal longshore currents The coastal water body (or bay) GE type can be divided into subtypes of inlets, basin and tidal flats All the inlets are relatively narrow but rather deep, 10 - 20m, functioning as tidal channels for water exchange between the bay and the sea On their beds, there is almost no fine - grained sediment except for the very coarse materials that may be products during the erosion time before submerging the region The basin subtype is shallow (2 - 4m deep) and sloping towards the frontal islands and inlets Finer - grained sediments pelitic mud) are accumulated in the centre and midle southeast while coarser -grained sediments and southwest side of the basin (sands and gravels) - mainly in the northwest side and even in some places, rocks are exposed in forms of bedrock or outcrop (median (aleurite and diametre) Finer - grained sediments are coarse of 0.071 - 0.100mm, So (sorting) aleurite with Md of 1.821 - 4.494 and S, (deviation) of 0.120 - 0.762, fine -aleurite mud with Md of 0.013 - 0.050mm, So of 2.544 - 5.809 and mlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Sk of 0.443 - 1.029, aleuritic - pelitic mud with Md of, 0.008 0.010mm, So of 2.682 - 3.286 and Sk of 0.858 - 1.291 Coarser - grained sediments are medium sand with Md of 0.369mm, So - 1.685 and Sk - 1.170 and fine sand with Md of 0.129 - 0.230mm, So of 2.102 - 3.036, and S, of 0.461 - 0.800 The tidal flat GE subtype is large in size, mainfested in the northwest and southwest side of the basin with high and low tidal flat forms The high tidal flats are composed of a mixture of aleurites, sands, aleurite mud with organic matter, debris of rocks and shells, pebbles and boulders The high tidal flats stretch in a tidal range of the mean level (2.1m) and the highest high level (4.7~), some of which are old benches covered sparsely with boulders and cobbles, especially mangroves However, mangroves grow well into forests on most of the flats of finer - grained sediments The low tidal flats, in a tidal range of the mean level and lowest low level, are composed mainly of sands and debris of shells Both the high and low tidal flats have been engraved by typical digitate tidal channels and creeks Belonging to the island which are inhabited GE type is the system of frontal islands, some of and smaller ones in the bay Most of the weathering crusts on the islands are coverd with vegetation but erosion and denudation activities in some places are active Especially, the southeast destroyed by waves, forming alternative 58 RQPONMLKJIHGFEDCBA slope of the frontal islands is cliffs and beaches Tuyin The c o a s ta l lo w com posed m a in ly of s e d im e n ts , GE e a rly a ll o f w h ic h in fra s tru c tu re b a s ic a lly la n d - a re ty p e o f tra n s p o rta tio n d e fo rm e d is m id le o c c u p ie d by hum an su-: tij,p 'Tai nguyen va M6i truang a lo n g th e H o lo c e n e n o rth w e s t and P le is to c e n e fo r a g ric u ltu re and irrig a tio n a c tiv itie s th a t and The have s id e o f th e d e te re d bay, u n c o n s o lid a te d in h a b ita n t re lie f Tij,p XaZYXWVUTS by la n d w ith its d e p o s its is p ro c e sse s in th e s e g e o lo g ic a l n a tu re The h ill and m o u n ta in w e a th e rin g c ru st c o m m o n ly d e lu v ia ls season w hy w a s h in g , and s e d im e n ts p e b b le s , b o u ld e rs N A TU R A L G E ty p e is n o rth w e s t e ro d in g and p ro lu v ia ls of th e bay d e n u d in g Such a re o f th e c h a c te riz e d p ro c e sse s g e o lo g ic a l m ix e d bay, and a c tiv e tie s w ith v e ry a re c o a rse by fo rm in g th e m a in m a te ria ls as s y s te m fo r a n d e v e n c o b b le s [4 , 1 ] RESOURCES OF THE BAY L iv in g R e s o u r c e s L iv in g (b io tic ) re s o u rc e s c o m m u n itie s 23 M a n g ro v e s flo a n d fa u n a w ith c e lll) , s p e c ie s N o n - L iv in g - liv in g d e fin e d as la n d s c a p e th e th e o c c u re n c e (a b io tic ) bay to u ris m , g e o lo g ic a l of o f th e (d e n s ity a life is th e th e y - s u p p o rtin g m a n g ro v e cover som e bay T he bay of 10 1 s p e c ie s _ e c o s y s te m ,4 0 c o n ta in s (d e n s ity x o f z o o b e n th o s h e c ta re s , an o f x w ith aboundaut - 10 X in d /rn " ), s p e c ie s and s p e c ie s of a re o f [4 , ] R e so u rc e s p o te n tia ls depend th a t o f p h y to p la n k to n re so u rc e s M ost The to w a te r o f th e m ost d e v e lo p w ay in c lu d e v a lu e s la rg e ly re so u rc e s on its and m a te ria l re la te s - liv in g - s a lin e and a base its im p o rta n t o f N a tu l its p o te n tia ls k a o lin , tita n iu m , re so u re s o f th e a q u a c u ltre , e tc ) bay e c o lo g ic a l fO T o ffsh o re p a rt fo r s o c io - fis h in g a re and S in c e to th e lo c a l e c o n o m y R e so u rc e s u n its c o n ta in c o m p o s itio n g e o lo g ic a l and (c o a l, iro n , of non b c k is h h a s c o n trib u te d e n v iro n m e n t m in e ls m in e ls tra n s p o rt, G e o lo g ic a l D is tr ib u tio n th a t as a re s p e c ie s o f a h ig h e c o n o m ic v a lu e s , a q u a c u ltu re The w o rk re so u rc e s w e ll a re a o f se a g ss, d e v e lo p m e n t o c c u r a ro u n d to ta l o f z o o p la n k to n s p e c ie s N on so s p e c ie s fis h e s , a m o n g w h ic h e c o n o m ic g ro w fo r % o f th e seaw eeds, bay O n e o f th e m o s t v a lu a b le s p e c ie s a c c o u n tin g o f th e and e n v iro n m e n t n a tu l geo u n its re so u rc e - d y n a m ic s w ith th e ir ty p e s The ow n 59 T u y ln tijp T'ai nguyen va M6i t.r u a n g properties as shown in the Table formations (except the titanium provide geosystem resources, potentials b ie n , T tip X Most of the minerals occur in the rock in old sand bodies) while others, substantially, which associate different values of use, in form of to develop local socio -economic sectors, among which are fishery and tourism.NMLKJIHGFEDCBA G E O D Y N A M IC S Reactivated differentially A N D D EV ELO PM EN T on the Caledonite structure, uplifting O F TH E BA Y the region is still in a situation of for which the Tienyen - Hacoi Bay was located in a relatively subsiding zone between the two uplifting zone - one in the northwest (called the Binhlieu uplifting zone) and the other in the southeast uplifting zone) These zones are distinguished southwest directed faults and also separated (the Vinhthuc by the two systems of northeast by northwest-southeast - faults, among which is the' well - known Tienyen active fault [6, 8, 9, 11] is located The relatively subsiding zone is recorded as a graben or a tectonic valley into which runoffs of the region are flowing Due to the runoffs in one time, the inlets of the bay were eroded to an extraordinary The sea - level rise unconsolidated leter sediments depth when the sea was far from the region submerged the valley and formed a sequence In the latest sea - level rise (in Holocene time), early - midle and late Holocene sediments of different origins were accumulated appearence of the Tienyen and Hacoi estuaries, by digitate deep channels the bay and its estuaries of whose tidal flats were engraved and creeks The current are characterized with the endogenous by the relative geodynamics of subsidence while exogenous processes - by the domination of the sea (tides) over the land (rivers) The northeast coastal area (Mongcai - Hongai) is influenced by the regular diurnal tide with such a wide range that its level is the highest of the Vietnam coastal zone as mlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 4.6 m in Cuaong, 4.7m in Tienyen or 4.9 m in the Changtay Island The runoffs flowing into the bay are very small, including Hacoi, Damha, Tienyen and Bache rivers, in which the Tienyen River is the largest but its discharge is 0.0347 x 10 ton of suspended just about 0.66 x l O"m" of waterand solid Though small in size, the discharge of rivers changes so extremely with seasons that its discharge in rainy season is - times higher than that in dry season These geodynamic features are the main dominated estuatries, estuaries), [4, 7, 12], with large reasons why there defined as drowned river valleys exist the two tide - (the first category of low and high tidal flats of sands, aleurites, gravels, pebbles and even boulders, in which mangroves grow well into forests, and why rocky shores of the bay have been deformed substantially rocky platforms have been 60 RQPONMLKJIHGFEDCBA covered almost with accumulative and their forms and T u y in mangroves into the ttip Tai nguyen v a M i tr z tiJ n g b ie n so - called tide and mangrove considered to be drowned sustainably by relatively coasts x T ~ p mlkjihgfedcbaZY ponmlkjihgfed The bay is now subsiding movements, sea level rise and poor supply of sediments T a b ls I, Geological distribution of natural resources Natural resources Geological environment Living Aquatic products I a Coastal Non - living Nearshore navigation, microclimatic marine GE type I b Coastal water Estuarine body(bay) (productive), GE type and mangrove ecosystems Potentials as much as tourism, shrimp ponds in high tidal flats and biodiversity, 30 species of a high economic value, as - a life communities supporting system for by fishing or gathering, important ecological maintaining functions stock, nursing; spawning for potentials conservation for and natural of wetlands for ecological and molluscan grounds in impounded by weirs, transport;maintaining table; water faits way water microclimate; function of burying land-based contaminant, water self tidal underground harmonizing environment and low landscape exchange -cleaning; a base with the sea for offshore fishing I c Island GE Terrestrial type accompanied covers vegetation with potentials faunas for natural conservation Minerals of construction materials, sands, kaolin, iron, coal, titanium; crystal function of a rocky wall against" strong wind fronts and high waves; and landscape potentials tourism, for ecological swimming beaches inhabited areas, (Vinhthuc Island) 2a Coastal low land GE type Fruit and including cereal cover, vegetation industrial tree, life - stock, Farming soil construction and sands, titanium In old sand bodies etc 2b Hill and Terrestrial moutain GE type life with numerous potentials cover and wild Diverse species of values, climatic vegetation for natural conservation, minerals, fresh harmonization, water tourism supply, potentials, etc etc SUSTAINABLY - ORIENTED Based on the integrated the highest benefit and USE OF THE BAY resource use of a coastal water body so as to effect enhance the quality of life but not to cornprormse 61 T u y ln tijp T a i n g u y e n environmental v a M i tr u a n g resources geological distribution b ie n T ijp x [1 - 5, 7] as well as values of the nature, of natural and renewal, sustainably and on the resources with their own properties of reserve - oriented uses of the bay can be proposed as follows: -(1)Development of ecotourism with activities of visiting diverse landscapes, especially mangrove forests, and link to the Traco, Mongcai and Halong tourist resorts (2) Development of aquaculture in low tidal flats impounding the flat with bamboo weirs but restriction of sands in way of of aquaculture ponds in mangrove forests (3) Development of natural conservation of what endow local SOClO - economy with direct or indirect values that include: - The geological and geomorphological values, some of which are nowhere to be seen, such as a system of marine terraces, a remain of a drowned graben-shaped valley, in which old benches and flatforms of rocky shore are now covered almost with sediments and mangroves, sometimes mangroves only, etc.NMLKJIHGFEDCBA - The landscape values emanating from the' diversity of relief and geological formations with native vegetation covers and their wonderful sights in inner and frontal islands, hills and the innermost, etc - The wetland northwest values, especially vegetated tidal wetlands along the side of the bay working as a spawning and nursing ground, visiting resort, etc.RQPONMLKJIHGFEDCBA C O N C L U S IO N • The geological environment geological environment of the Tienyen - Hacoi Bay belongs to the type of coastal water bodies, composed of the Paleozoic and Mesozoic rock (both crystaline and sedimentary) covered with Quaternary sediments and structured basement into surfacial units of inlet, basin and tidal flat subtypes covering for some 400 sq.km in area The inlets are deep and narrow, known as a result of erosional processes in the past, in which there is almost no newly - accumulated sediments W hereas, the basin and tidal flats are large in size, resulting from the old platform of rocky shores submerged and covered with sediments and mangroves • The Tienyen - Hacoi Bay with its estuaries 62 formed in the late Holocene T u y ln time is located in a graben sustainably in conditions sediments and tijp Tai nguyen v a M i tr u im g - shaped relative subsiding b ie n x T i j p ponmlkjihgfedcba zone, drowned of the sea - level rise and the poor supply of characterized by the dynamic domination of the sea (tides) over the land (revers) • Living resources of the Tienyen - Hacoi Bay nave more values than non living resources, indirect the value of direct resource use is lower than that of resource use, the value of reserved resources than that of what are being used and the integrated is much higher resource use of a coastal system is the best way to effect the highest benefit REFERENCE Nguyen Huu Cu et a1.,1994 Geological Environment Characteristics Stored in the Haiphong Institute of the Halong Bay Survey Report, of Oceanology Nguyen Huu Cu, Tran Due Thanh and Dinh Van Huy, 2000 Methodology Report of Studying of the Institute Project Coastal W ater Managed by Bodies NCST, of Vietnam Stored in Component the Haiphong of Oceanology Nguyen Huu Cu, Tran Due Thanh and Dinh Van Huy, 2001 Rationale Component Haiphong Use Orientation Report Institute for of the the Project Chanmay Managed and by NCST, Danang Bays Stored in the of Oceanology Nguyen Huu Cu et e1 , 2003 Additional Resources Survey on Physical and Environment Use and Development in the Haiphong of the Tienyen Report Institute Conditions, of the Project Socio - Economy, Natural - Hacoi Bay for Sustainable Managed by NCST, Stored of Oceanology 63 T u y in tijp T ng ayen va uang M o i tr T t i p mlkjihgfedcbaZYXWVUTSRQPONMLKJIH X b iin Nguyen Due Cu et al., 1994 Survey on Tidal W etlands Vietnam Survey in the Coastal Area and Islands in Northest Report, Stored in the Haiphong Institute of Oceanology Nguyen Van Giap, Phung Van Phaeh, 2000 Geodynamic and Structure Systems in the Northesast Characteristics of Marginal Faulting of the Tonkin gulf Contr mar geol geoph Vol VI, Sci Techn pub House, Hanoi, p 123 - 131 Nguyen Chu Hoi at al., 1990 Study of Rationale use of Tidal Marshes in North Vietnam Report (vol 1) of the project 48B - 05 - 02, Stored in the Haiphong Institute of Oceanology Nguyen Cong Luong et el., 1999 Geological and Mineral Map of Hongai in a Scale of 200,000 and Description Gen Dep Min Geo Vietnam Nguyen Cong Luong et eI., 2000 Geological and Mineral Map of Hongai in a Scale of 200,000 and Description Gen Dep Min Geol Vietnam 10 Nguyen Ngoe, Pham Hoang Hai, Le Due An, 2001 Coastal Marine Islands of Vietnam Report of the Project Managed by NCST, Stored in the Hanoi Institute of Oceanography.RQPONMLKJIHGFEDCBA 11 Nguyen Ngoe, 2000 Geological and Mineral Component Report Haiphong Institute Features of the Tienyen - Hacoi Bay Region of the Project Managed by NCST, Stored in the of Oceanology 12 Tran Due Thanh et el , 1985 Geology and Geomorphology of the Coastal Zone in North Vietnam Component Report of the Project 48 - 06 - 14, Stored in the Haiphong Institute 64 of Oceanology T u y in tg p Tai nguyen va M 6i tr u o n g b ie 'n T g p X 13 Nguyen Van Tien and Le Thi Thanh, 2002 Living Resource Potentials of the Tienyen - Hacoi Bay Component Report of the Project Managed by NCST, Stored in the Haiphong Institute of Oceanology 14 Luu Ty et at, 1969 Geology and Landform of the Damha - Mongcai Coastal Area Survey Report, Stored in the Haiphong Institute of Oceanology TOM TAT MOl TRU'ONG DJA CHAT VJNH TlEN YEN - HA COl N guy€n D in h Van H iia H uy, N guy€n Ca, N g u y € n N guy€n Q uang Th] Phuong N goc, T r tin T u tin , N guy€n H oa, N guy€n D tic Thonh, V ii T u tin , T h i K im D ij,n g H o a i Vinh Tien Yen - Ha Cai 113m ot vinh dai tren 50km va r