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

Coastal water Estuarine and mangrove ecosystems Potentials for ecological and landscape bodybay GE productive, biodiversity, as much as tourism, shrimp ponds in high tidal flats and type

•

~

,,? "

TArNG'UYEN

VA MOl TRUONG BIEN

T ~ P X

B a n b ie n t~ p :

T ru d n g b a n :

'I'h tr k y :

C a c tb a n h v ie rn

P G S , T S N g u y en V an T i~ n

T S N g u y e n H u y Y ~ t

T S N g u y en D u e C u

T S N g u y en H u u C li

T S L u u V an D i~ u

T S T rlln D u e T h ~ n h

T S D b C o n g T h u n g

M

N H A X U A T B A N K H O A H Q C v A lIT T H U A T

H A N o r - 2 0 0 3

T r a n D u e T h a n hcbaZYXWVUTSRQPONMLKJIHGFEDCBA

4 G e o lo g ic a l E n v iro n m e n t o f th e T ie n y e n - H a c o i B a y 5 4

N g u y e n H u u C u , N g u y e n N g o e , T r a n D u e T h a n h ,

D i n h V a n H u y , N g u y e n Q u a n g T u a n ,

N g u y e n V u T u a n , N g u y e n T h i P h u o n g H o a ,

N g u y e n T h i K i m A n h , D a n g H o a i N h o n

N g u y e n V a n T i e n , N g u y e n H u u D a i

6 R e se a rc h e s in D istrib u tio n o f V ie tn a m e se S e a g ra sse s 7 6

N g u y e n V a n T i e n

7 C a u tru e v a tie 'n h o a d ia c h a t v u n g b a i b 6 i y e n b i~ n N g h ia H u n g 8 9

N g u y e n H i i u C l l , T r t i t i D u e T h a n h , N g u y e n v a T u r i n ,

N g u y i n Q u a n g T u r i n , D i i n g Hoai Nhan,

N g u y i n T h i K i m A n h , B u i V a n Yumig

8 D a c tru n g h in h th a i - d o n g lu c v a b ie n d a n g b o H a i H a u , N a m D in h 1 0 6

Dinh V a n H u y , D 6 D i n h C h i e n ,

T r i i n D u e T h a n h , B u i V a n V z i < ; J n g

9 M o t su u t? -p h o a th a c h tru n g 16( F o r a m i n i f e r a ) M io x e n m u o n it d u o c b ie t 1 2 6

d e 'nONMLKJIHGFEDCBAd k h u Y I;iCb 6 n tra m tic h D ~ ta m y e n b i~ n D 6 n g H d i (Q u a n g B in h )

N g u y i n N g o c , N g u y i n Hiiu C l l

1 0 B u d c d fiu d a n h g ia ta c d o n g c u a h 6 H o a B in h d 6 i v d i n g u o n le i c a b i~ n 1 3 9

y e n b o

r e s u l t s o f

± 7 1 4 % ,

, C d , A s ,

± 0 5 1

-MVC Ll)C

k d e s i g n ,

~ Q A / Q C

la r e h i g h t

L e i n 6 i d fiu

1 4 5 n a rn h o a t d o n g v a p h a t tri~ n c u a P h a n v ie n H a i d u o n g h 9 C ta i H a i

P h o n g (1 9 5 9 - 2 0 0 4 )

N g u y i n V a n T i e n

2 C o a sta l E ro sio n a n d S e d im e n ta tio n in V ie tn a m

T r a n D u e T h a n h , P h a m H u y T i e n ,

B u i H o n g L o n g , N g u y e n V a n C u

3 R e se a rc h e s in E stu a rin e E n v iro n m e n t a n d E c o sy ste m o f R e d R iv e r: A n

O v e rv ie w o n A c tiv itie s a n d R e su lts

1 1

T r t i n D u e T h C J - n h , D 8 D i n h C h i e n

K h a n a n g ta c d e )n g c u a m o t so ' h in h th irc n u o i th u y sa n d e 'n m 6 i tru o n g

v u n g b i~ n y e n b o H a i P h o n g

L u u V a n D i e u

H ie n tra n g , x u th e ' b ie n d 6 i m o i tru o n g d ia h o a tra m tic h d fim n u 6 i t~ i

v u n g y e n b i~ n H a i P h o n g , 1 2

N g u y i n T h i T h u n u « N g u y i n D u e C u

M o t so ' d § n lie u v g a n h h u o n g c u a c a c m u o i d in h d u d n g ( P 04 -, N O ;) d 6 i

v d i m a t d e ) te ' b a o q u a n x ii th u c v a t p h u d u ta i v in h H ~ L o n g

N g u y i n T h i M i n h Huyen, C h u V a n T h u o c , v a T h i L u u

1 3

T ra n g

3

5

2 0

3 4

1 6 1

1 7 1

1 8 2

349

Nguyen Huu Cu, Nguyen Ngoe, Tran Due Thanh,

Dinh Van Huy, Nguyen Quang Tuan,

Nguyen Thi Kim Anh, Dang Hoai Nhon

Tuyln tgp TaiRQPONMLKJIHGFEDCBA n g u y e n va M6i t r u a n g bien TgpNMLKJIHGFEDCBAx

GEOLOGICAL ENVIRONMENT

OF THE TIENYEN - HACOI BAY

districts of Vandon, Tienyen, Damha, Haiha and M ongcai are living

the years 2002 - 2003 in the NeST project conducted by the HIO

3 GEOLOGICAL ENVIRONM ENT STRUCTURE

3.1 Basem ent Rocks

3 1 1 C r y s t a l i n e R o c k s

biotite granite and aplite of the Pia Oac complex, 4 km north of the bay

3 1 2 S e d i m e n t a r y R o c k s

650m thick in the south, with Triassic rocks of the Binhlieu formation (tuffaceous

(Lc) - Island G E typeRQPONMLKJIHGFEDCBA

3 2 C o v e r i n g D e p o s i t s

3 3 S u r f a c i a l S t r u c t u r e

(fig 1) [4] :

(1) - Coastal G E system

- Inlet G E subtype

- Basin G E subtype

- Tidal flat GE subtype High tidal flat form Low tidal flat form

Y JponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

\0,'1 M

JJ:

30'

1)0'RQPONMLKJIHGFEDCBA l.a

~

~

~)

;:s

c::

~,

~

•

•

"1

;:.

~,

;:s

()Q

0-•

~)

;:s<

~

.~)

~

><

1 -lO'

LE G E N D

.

1234567

3 • B asin G E 5utype, 4 • Tidal flat G E subtype:

-~ 7 • •• , ~~o;;;'Cal'

1 0 1 - I , c r

~.iii· · · ::"""' ' '.', '/.';(T"j 1IIII1

" I {- r , ' '

C H IN A

7

~

~). •

.~)

~ -s

~,

•

11

10'

Iori ·

S cale - 1: 200 000

II,,·

0 1

-l

F i g u r e 1 Geological environm ent structure of Tienyen Hacoi Bay region

T u y l n t g p T a i n g u y e n v a M6i t r uang bien T g p x

(2) - Land G E system

(2a) - Coastal low land G E type

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 3 subtypes of

(deviation) of 0.120 - 0.762, fine -aleurite mud with M d of 0.013 - 0.050mm, So of 2.544 - 5.809 andmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBASk of 0.443 1.029, aleuritic pelitic mud with M d of, 0.008

with M d of 0.129 - 0.230mm, So of 2.102 - 3.036, and S, of 0.461 - 0.800 The tidal

of the basin with high and low tidal flat forms The high tidal flats are composed

the mean level (2.1m) and the highest high level (4.7~), some of which are old

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

Tuyin tij,p 'Tai nguyen va M6i truang su-: Tij,pXaZYXWVUTSRQPONMLKJIHGFEDCBA

T h e c o a s t a l l o w l a n d G E t y p e i s a l o n g t h e n o r t h w e s t s i d e o f t h e b a y ,

c o m p o s e d m a i n l y o f e a r l y - m i d l e H o l o c e n e a n d P l e i s t o c e n e u n c o n s o l i d a t e d

s e d i m e n t s , a l l o f w h i c h a r e o c c u p i e d f o r a g r i c u l t u r e a n d i n h a b i t a n t l a n d w i t h i t s

i n f r a s t r u c t u r e o f t r a n s p o r t a t i o n a n d i r r i g a t i o n T h e r e l i e f b y t h e s e d e p o s i t s i s

b a s i c a l l y d e f o r m e d b y h u m a n a c t i v i t i e s t h a t h a v e d e t e r e d g e o l o g i c a l p r o c e s s e s i n

n a t u r e

5 9

T h e h i l l a n d m o u n t a i n G E t y p e i s n o r t h w e s t o f t h e b a y , c h a r a c t e r i z e d b y

w e a t h e r i n g c r u s t w a s h i n g , e r o d i n g a n d d e n u d i n g p r o c e s s e s a n d f o r m i n g

c o m m o n l y d e l u v i a l s a n d p r o l u v i a l s S u c h g e o l o g i c a l a c t i v e t i e s a r e t h e m a i n

s e a s o n w h y s e d i m e n t s o f t h e b a y a r e m i x e d w i t h v e r y c o a r s e m a t e r i a l s a s

p e b b l e s , b o u l d e r s a n d e v e n c o b b l e s [ 4 , 1 1 ]

4 N A T U R A L R E S O U R C E S O F T H E B A Y

4 1 L i v i n g R e s o u r c e s

L i v i n g ( b i o t i c ) r e s o u r c e s o f t h e b a y w o r k a s a l i f e - s u p p o r t i n g s y s t e m f o r

c o m m u n i t i e s O n e o f t h e m o s t v a l u a b l e r e s o u r c e s i s t h e m a n g r o v e e c o s y s t e m w i t h

2 3 s p e c i e s M a n g r o v e s g r o w s o w e l l t h a t t h e y c o v e r s o m e 1 6 , 4 0 0 h e c t a r e s ,

a c c o u n t i n g f o r 4 0 % o f t h e t o t a l a r e a o f t h e b a y T h e b a y c o n t a i n s a n a b o u n d a u t

f l o r a a n d f a u n a w i t h 1 9 4 s p e c i e s o f p h y t o p l a n k t o n ( d e n s i t y o f 1 9 x 1 03- 7 0 9 X 1 03

c e l l l ) , 7 2 s p e c i e s o f z o o p l a n k t o n ( d e n s i t y o f 1 03 2 5 7 x 1 03 i n d / r n " ) , 5 4 s p e c i e s o f

s e a w e e d s , 5 s p e c i e s o f s e a g r a s s , 1 1 0 s p e c i e s o f z o o b e n t h o s a n d 1 8 3 s p e c i e s a r e o f

f i s h e s , a m o n g w h i c h a r e 3 0 s p e c i e s o f a h i g h e c o n o m i c v a l u e [ 4 , 1 3 ]

4 2 N o n - L i v i n g R e s o u r c e s

N o n - l i v i n g ( a b i o t i c ) r e s o u r c e s i n c l u d e m i n e r a l s a n d p o t e n t i a l s f o r s o c i o

-e c o n o m i c d e v e l o p m e n t M o s t o f t h e m i n e r a l s ( c o a l , i r o n , k a o l i n , t i t a n i u m , e t c )

o c c u r a r o u n d t h e b a y T h e m o s t v a l u e s o f n o n - l i v i n g r e s o u r e s o f t h e b a y a r e

d e f i n e d a s p o t e n t i a l s t o d e v e l o p b r a c k i s h - s a l i n e a q u a c u l t r e , e c o l o g i c a l a n d

l a n d s c a p e t o u r i s m , w a t e r w a y t r a n s p o r t , a n d a b a s e f O T o f f s h o r e f i s h i n g S i n c e

t h e 1 9 6 0 s , a q u a c u l t u r e h a s c o n t r i b u t e d i t s i m p o r t a n t p a r t t o t h e l o c a l e c o n o m y

4 3 G e o l o g i c a l D i s t r i b u t i o n o f N a t u r a l R e s o u r c e s

T h e g e o l o g i c a l e n v i r o n m e n t a n d i t s u n i t s c o n t a i n n a t u r a l r e s o u r c e t y p e s

t h a t d e p e n d l a r g e l y o n i t s m a t e r i a l c o m p o s i t i o n a n d g e o - d y n a m i c s T h e

o c c u r e n c e o f r e s o u r c e s r e l a t e s g e o l o g i c a l e n v i r o n m e n t u n i t s w i t h t h e i r o w n

T u y l n t i j p T'ai n g u y e n v a M6i t r u a n g b i e n , T t i p X

tourism.NMLKJIHGFEDCBA

among which is the' well - known Tienyen active fault [6, 8, 9, 11] is located The

runoffs of the region are flowing Due to the runoffs in one time, the inlets of the

exogenous processes - by the domination of the sea (tides) over the land (rivers)

coastal zone asmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA4.6m in Cuaong, 4.7m in Tienyen or 4.9m in the Changtay Island The runoffs flowing into the bay are very small, including Hacoi, Damha, Tienyen

T u y i n t t i p T a i n g u y e n v a M 6 i t r z t i J n g b i e n T ~ pmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAxponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

mangroves into the so - called tide and mangrove coasts The bay is now

considered to be drowned sustainably by relatively subsiding movements, sea

level rise and poor supply of sediments

61

I a Coastal Aquatic products Nearshore navigation, microclimatic

marine GE type

I b Coastal water Estuarine and mangrove ecosystems Potentials for ecological and landscape

body(bay) GE (productive), biodiversity, as much as tourism, shrimp ponds in high tidal flats and

type 30 species of a high economic value, molluscan grounds in low tidal faits

as a life - supporting system for impounded by weirs, water way communities by fishing or gathering, transport;maintaining underground water important ecological functions for table; harmonizing microclimate;

maintaining stock, spawning and environment function of burying land-based nursing; potentials for natural contaminant, water exchange with the sea conservation of wetlands and self -cleaning; a base for offshore

fishing

I c Island GE Terrestrial vegetation covers with Minerals of construction materials, crystal

type accompanied faunas potentials for sands, kaolin, iron, coal, titanium; function

natural conservation of a rocky wall against" strong wind fronts

and high waves; potentials for ecological and landscape tourism, swimming beaches (Vinhthuc Island)

2a Coastal low Fruit and cereal vegetation cover, Farming soil and inhabited areas,

land GE type including industrial tree, life - stock, construction sands, titanium In old sand

2b Hill and Terrestrial vegetation cover and wild Diverse minerals, fresh water supply,

moutain GE type life with numerous species of values, climatic harmonization, tourism potentials,

potentials for natural conservation, etc.

etc.

6 SUSTAINABLY - ORIENTED USE OF THE BAY

Based on the integrated resource use of a coastal water body so as to effect

the highest benefit and enhance the quality of life but not to cornprormse

- The landscape values emanating from the' diversity of relief and

visiting resort, etc.RQPONMLKJIHGFEDCBA

-(1)Development of ecotourism with activities of visiting diverse landscapes, especially mangrove forests, and link to the Traco, M ongcai and Halong tourist resorts

mangrove forests

-economy with direct or indirect values that include:

- The geological and geomorphological values, some of which are nowhere

mangroves only, etc.NMLKJIHGFEDCBA

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

mangroves

T u y l n t i j p T a i n g u y e n v a M 6 i t r u i m g b i e n T i j pponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAx

(tides) over the land (revers)

coastal system is the best way to effect the highest benefit

63

REFERENCE

1 Nguyen Huu Cu et a1.,1994

4 Nguyen Huu Cu et e1 , 2003

Coastal M arine Islands of Vietnam Report of the Project M anaged by

NCST, Stored in the Hanoi Institute of Oceanography.RQPONMLKJIHGFEDCBA

5 Nguyen Due Cu et al., 1994

Survey on Tidal W etlands in the Coastal Area and Islands in Northest

Vietnam Survey Report, Stored in the Haiphong Institute of

Oceanology

6 Nguyen Van Giap, Phung Van Phaeh, 2000

Geodynamic and Structure Characteristics of M arginal Faulting

Systems in the Northesast of the Tonkin gulf Contr mar geol geoph

Vol VI, Sci Techn pub House, Hanoi, p 123 - 131

7 Nguyen Chu Hoi at al., 1990

Study of Rationale use of Tidal M arshes in North Vietnam Report (vol.1) of

the project 48B - 05 - 02, Stored in the Haiphong Institute of Oceanology

8 Nguyen Cong Luong et el., 1999

Geological and M ineral M ap of Hongai in a Scale of 1 200,000 and

Description Gen Dep M in Geo Vietnam

10 Nguyen Ngoe, Pham Hoang Hai, Le Due An, 2001

9 Nguyen Cong Luong et eI., 2000

Geological and M ineral M ap of Hongai in a Scale of 1 200,000 and

Description Gen Dep M in Geol Vietnam

11 Nguyen Ngoe, 2000

Geological and M ineral Features of the Tienyen - Hacoi Bay Region

Component Report of the Project M anaged by NCST, Stored in the

Haiphong Institute of Oceanology

Geology and Geomorphology of the Coastal Zone in North Vietnam

Component Report of the Project 48 - 06 - 14, Stored in the Haiphong

Institute of Oceanology

5- TTTNponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 65RQPONMLKJIHGFEDCBA

13 Nguyen Van Tien and Le Thi Thanh, 2002

Living Resource Potentials of the Tienyen - Hacoi Bay Component

Report of the Project M anaged by NCST, Stored in the Haiphong

Institute of Oceanology

14 Luu Ty et at, 1969

Geology and Landform of the Damha - M ongcai Coastal Area Survey

Report, Stored in the Haiphong Institute ofOceanology

TOM TAT

MOl TRU'ONG DJA CHAT VJNH TlEN YEN - HA COl

H ai Ha va th] X8 M 6ng C ai quan IY·

Jura cua h~ tang H a C aL

tong chieu day dat tren 10m

phan chia thanh cac phan v] sau: