Một số đặc điểm địa mạo vùng biển quốc gia cát bà tuyển tập tài nguyên và môi trường biển, tập 1, tr 19 25 NXB khoa học và kỹ thuật

V I.S N

TRUNG

.T A M

KHOA

N G H I~ N

HQC

CUU

V Ie T

B I~ N

NAM

HAl

PH 0N G

alor yen
.••.

va

r
i

V le N

TRUNG

KHOA

T A M N G H Ia N

HOC

V Ie T

CUU

NAM

B II!N H A l P H O N G

TAl NGUYEN VA MOl TRU'ONG BIEN
(TOM TAT CAC CONG TRiNH NGHIEN c o u 1986 - 1990)

NHA

XUAT

BAN KHOA
HA

N (> I -

HQC
1991

vA

K Y T H U !T


M()C L()C
T rang
UTi

g /& i

/h i~ u ZYXWVUTSRQPONMLKJIHGFEDCBA

2. N O i

dung

b a n d o d ia

1.

th e m

vung

m a o,

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c a u t ru c + -h ln h th a i,

huang

ty

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I ~ 1 /2 0 0 0

Sa

lu e c d a n h

g ia

hi e n

M O t s6 d~ c

d i e m d ja

tr a n g d a i b o b ie n

m ao

v itn g

b i~ n

Ha

iPh

6.

H ln h
K im

a

t r ie u

H ~ Ia c h

th a i,

dai

pha n b6

i Ph

b e b ie n H a
T r l1 n

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tra m

tlc h

va

d~c

d ie m

8.

ng

co

ta y v j n h

D an

ban

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do t

lie u

v~

a

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muo n

t tr l i e u v i~ n

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M O t s6
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Ba
T r l1 n

D ue

b l)i

Va

i

26

H uy,

tu b a

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i b l)i

H ew

yen

b ie n h u y e n

cua

cac

b b n tie h

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t1 ,l h ie n

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da

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i t ie u

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b ie u

a

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d~c

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da

i

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39

h a th a p

bc

yen

rm r c

ba c

dO ng

b ie n

vao

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cu6i

H o lo x e n

g ifra -d Ilu

d ie m

dj a hoa

tr a m

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48

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tic h

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ng ap m an

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b ie n

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60

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t ir

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III ( F o r a m in ife r a )

th b

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67
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11.

_

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19

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th a m

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9.

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33

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bo

th a i

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T ran

7.

g ia

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D in h

D in h

Phom

H O i,

qu6e

o ng+Q ua

ThQ nh.

San,

o ng qua

C hu

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5.

trb -h ln h

7

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4.

ch am

000

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3.

5

tro n g

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155


and others.fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
A p p lic a tio n
of
r e m o le
s e n s in g

3. M.C Gupta.

m o n ito r in g

4. Nguyen

Chu

h i~ n

of

c o a s ta l

e n v ir o n m e n t

H(}i va nnk.

tr q .n g

in

ilC iu sir d r .tn g

Bu& c

tu

te c h n iq u e s

ISRO. India,

In d ia .

li~ u

v i~ n

fo r

1989.

ila n h TSRQPONMLKJIHGFE
g ia

th o m

b ie n hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

H ( i i P h o n g . Tai nguyen va rnoi truong bien,

ven

Ha i

Q u a n , s 6 6 /1 9 8 9 .

5. Tr~n

Due Thl1-nh va nnk.
Ba o cao luu

f)la

c h .a t

trf! ta i Trung

-

ilia

tam

m(1O

ddi

Nghi en ciru

N am .

B a c V t~ t
Hai Phorig,

ven

ber

bien,

1985.

SUMMARY
PRELIMINARILY
HAIPHONG

ASSESSING

COASTAL

THE

ZONE

BY

PRESENT

REMOTE

STATUS

SEr~SING

The
c o v e r in g
The
changes
e r o s io n a l
and

th e

a u th o r s
s e r ie s

have

of

of
H a iP h o n g

a n a ly s is

and
m a jo r

c o a s ta l

g e o m o r p h ic

and

estuarine

of

im a g e r y

c o a s ta l

L andsat

d e p o s itio n a l

MQT

a s tu d y

s e n s in g

in H a iP h o n g

o b je c ts

ln

pursued

r e m o te

in

order

to

Cuong

w e ila n d s

c o a s ta l

an d

by

e v a lu a te

zone.

im a g e r y

in d ic a te d

z one d u r in g

1976 -

s ig n ific a n t

coast

-

lin e

1986"

c o m p le x

of

w ere

n o tic e d ,

fe a tu r e s

have

b e r e d e s c r ib e d .

V U 'O 'N

V ie t

d is c o v e r

changes

so f>k-c

Hoi

C k«

N guyen
N guyen

v a r io u s

OF

DATA

to o .

TJ1e

The

:;o a ::;ia I !a n d fo r m

9 I E M f)IA M ~ O \'lU N G B lb ~

Q uae

G IA

CAT sA
f)inh V a n

T

ran

Bue

H uy
T h q .n h

Vung bien v u o n quoc gia (VQG) Cat Ba thuQc quail dao Cat Ba, Hai
Ph on g - mOt qulin dao d a voi I a n nh at & ven b o tay Bien D o n g . Dia hlnh
vung bien VQG het s u e phrrc tap, do c da o "oi nhie u ca D !1 d~p hiern co, ha:p
da:n du k hach t r ong va ng oai nu o c. Day lit nrr i tr anh g io bao tot cho tau
thuyen v a co he thong lubng Iac h sau dan tau bie n vao cf!~ cang Clia L1,1c,
Hon Gai va Hcii Phong.
H~ thong am tieu san h5 vien b6" a vung bien la noi
ltru gill nh ieu nguon gen sinh v~t qui hiern v a nhieu Io ai "i;ic san noi (ieng.
D~c diem dja rnao vung bien VQG rno i chi duqc d e c~p S;y luge trong
mot s6 cong tr lnh ng hie n ctru tru o c day [2. 3. 6. 7]. Bai ,jet nay la Ian
dau tien cong b6 chi tie t ve dia ma o vung bien VQG thunc quan d8.0 Cat Ba.
Tu lj~u sir dung tr ong bai Ia ket qua cua nhieu dQ'~ d ie u tra khao SeH trong
nhung narn gan day. di;ic biet Ia d o t kh ao sat lap lu~n chsrng ~inh ti5 k y thuat
do Trung
tam Ng hien cuu

bien Hai Pho ng tie D hanh narn 1989. Ngoa i t11'
Iieu t htrc di a cua c a c dor k hao s a t bang x u o n g v a ta u 33 CV, con s ~ dung
U ti lieu phan tieh cac hili d o va Iuc d o trong
va, ngoai
nucc t5 r j~ : 1/250001/50000.
anh may bay ty 1~ 1/30000
(flam 1985) va cac he; fmh.v~ tinh Landsat ty l¢ 1/100000
(cac narn 1986. 1989)" Cac tir li~ugoc
va die so d o dia,
h lnh, dja rna o t han h lap 0 ty l~ 1 /25000 thi~n, dang luu fE -fr t?i trun g tam
nghien ctru bien-fIcii Pho ng.
.

19


1. KHAI

QuAT

v~

DJA

HINH

VUNG

BIEN

VQG

i ngap chim hl5t
Vung' bien VQG Cat Ba 18. mOt vun g dja hlnh caxta b hgfedcbaZYXWVUTSRQPON
.s irc phuc tap va hiern c6 tr e n th~ giai. N g oai oao chinh, to an v u n g c6 137
dao nho, cao nhflt la hon Giao Oi (149m), rong nhat la da o Dau Be (3S0ha)
va chi c6 k hoang 39 ho n rOng t re n Sha. DO c a o cac da o t?P trung
trong cac
khoang 120 -150m.
80-100m,
40-60m.
20-30m.
MOt s6 hon chi cao 10 -15m.
Cac dao c6 hln h dang ky dj , ba d ao c6 nhieu rnu i nho, cung 16m va nhieu
vacbbo
d6c dung chan c6 ngan ~n man h6a hoc. Da s6 cac dao c6 them san
ho v ien quanh
va tre n da o c6 ho rnro e man.

Hau he t dj~n tich vung bien VQG narn trong dir o n g dting sau 20m, nai
sau nhat (35m)fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
a gan h o n V~ Gia Con. Vj nh Lan Ha s au trung blnh 13m.
DO s au 10 - 15m c hu yeu a true La ch Nga n va Iac h D au Xuoi , Die n tich
cua tung, arig ch i ern kho ang 45% d ie n tich vung bien. s a u trung blnh 3-4m,
va n arn trong dtrang d ting s au 12m. Cac tung ang Ian deu ch ay theo phtro rig
DB - TN, dai 4 - 8km, cua rOng 400-1200m.
s a u 6-10m.
va phb bien them
san ho vien quanh
tao nen cac vting nho , kin va rnra kin, v a c6 hlnh thai

gi6ng am tieu vong ,
To an bO d o i tr ie u cua vung rOng 815 ha v a i dO cao thu o ng khoang
HD, tr ung blnh 0,5 m/Om HD. DO c a o 2 - 4m/Om
HD chi c6
it a cac ba i tich tu do s6ng.

0- 1m/Om
r~t

2. DJA

M~O

BO' BIEN

VQG

BO' bien
mom

VQG khuc k huyu, qua nh co hi chia cat bo i h~ th6ng cac dao,
da nga m, rnfl i nho, am t ieu san ho, tung ang va cac ranh, h6 ng arn.

a day vao kieu b a caxto
bi
Shepard
F.[ 1] c6 the x~p b c bien TSRQPONMLKJIHGFEDCBA
ng ap chlrn . Mot s6 ta c gia [2, 3, 6, 7J xep b o bien & day v a o k ieu an mon
.hoa hQc. Thir c t~ dja hlnh b a a day r at ph ire t ap,

Theo

- C A e D ~ N G v A cxc

y~ u

T O DJA H IN H B O '

+ Y a c h v d s u o n b o - . Vach va su c n b a da vOi vQG hau h~t la d6c dung
va duoc hlnh thanh
do qua tr lnh t r tr o t la, sup db tr ong Iuc hoac do qua
tr lnh m id rn on va ho a tan rua Ifia cua mrc c bien. C6 noi do e~u t a o dia chat,
c ac lop da vt>i d .m x ie n ch e o ta o r a cac vach tr eo (d6e tr e n 90°). C6 no i
cac l&p da vOi xen s i lit nghieng
tho ai t ao nen d ja hlnh kieu d o n nghieng
[cue s ta}, Tr en vach va suc n d6e thuong
ba.t g~p cac ngliD bien cb, v~t ha
cb barn cao 2-2.5m,
3-4m.
c6 khi ta i 5-6m.
Chan vach co the la bai tang,
(:uOi, soi, darn hoac them rnai rno n va th e m san hO hoac them tlch tl) va b:ii
cat bien,

+ N g { [ n a n m a n h 6 a h Q c . Phat tri~n chu y~u trong pharn vi dao dOng
rnuc rnro c trleu. ChUng thtrang
c6 dO cao 2 - 3.5m, lorn sau vao kh6i nui
cht.Jc centimet
dEn 10 -15m, va hlnh thii cua chung r~t khac biet nhau
ng~n do n, ng~n kep, ng~n d6i xung. ngan khOng d6i xting ..• phu thuOc

th anh ph an, c'u t,o da g6e va di~u ki~n dOng Iuc cua bien,

20

eua
va i
nhtr
vao


+ TSRQPONMLKJIHGFEDCBA
Hang
l u l } n fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
v a zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
cu-a t h t m g la nhung
dang dja hinh doc da o tham gia tao
nen c anh quan dep cho vuo n. Chung
cling duo c hlnh th an h chu y€u do an
rnon h6a hoc, Hang c6 the cao 5-6m,
rOng 12 -15m, sau hang ch u c met (hang
Xich, hang Thting ... ) va la to h o p cua cac ng an hi en da i va ngan co da i. .
Cac cua thong hep thuang
c6 hlnh d6i xung
hai hen, hlnh dau ng o ac don
v a n g an an m o n k h a s au.
+ T h ~ m m id m o n duo c ta o nen b a i ca c qua trlnh mai m o n ctia s6ng bi en, an
mon h6a hoc va xarn thirc cua dong tr ieu, T'hern phat tr ie n chu yeu a no i
co s6ng ma nh nhtr khu dong nam (DN) Vuan
va D~u B~. Be mat them
thuo ng cao ngang muc

bien
trung
blnh
va rOng m ot vai met d€n hon
chuc met. Pha n tr en phia v ach doc them thtro ng 10 da goc va k ha phang ,
phan duoi thtr c n g duo c tich tu cac san pharn v un pha huy do s6ng.
+

T iw m t f c h t u v a c l~ c a t c b Ia nhtrng dang tich tu b a narn cao han mu c
trieu cuo ng hie n nay. Chung thu o ng phan bo & cac cung b a lorn v a duQ'c
cau ta o chti yeu bai cac vo sinh vat, d o ca o c6 the da t 2-2,5m
toi 3-3.Sm.
Tr e n mat them phat tr ien c a c loa i ihvc v1).t luc dia . Cac de cat & DUQ'ng
Gianh cao 2 - ~m. dai tlr vai tram toi hon ngan met d uo c dong doc bo va
song th a nh tao nen k ho ang 2-1 ng an narn truce, Cat c6 thanh phan chti yeu
Ia tha ch anh,

+ C a e b a i b i~ n do s6ng vun tu , e6 t ren 20 bai, chti y€u ph an bo akhu
DN va Dau Be tao ra cac bai tam d e p nhir Cat Co, Cat Drra ... DO cao ' cua
bai t hir o ng tlr 1 - 4 m /0 m
HD, r o ng vai chuc den ho n tram met, dai v ai ch u c
met d en 20Vmet.<,::at tao bai Ia vo v oi sinh vat va thuo ng narn tr en ria them
san ho.
+ C a c b a t triE lu Ia c a c ba:i th a p bun bOt, set x a m phot xanh , c hu yeu phan
bo a phia b ac , Bai tr i eu Ang K e rong n hat to i 50 ha, cao (rung bmh 0 , 5 m f O m
HD Cac bai kh ac yen La ch Ng an chi rong 3-5
ha. a mo t so n o i tr enjnat
hili c6 thuc vat ng ap m an mQC thua thot ,
+ T h E lm
san h a la mot da ng dj a hlnh b o d~e tr un g , dec dao cua Vuan. co,

d ien tich khoang 350 h a. D¢ cao ma t them ttr Irn tren den 1m duo i Om HD'j
r¢ng tir va i chuc met deri ba b6n tram met. Be rn a t ngh ieng rat thoai (0,002)'
tir v ac h n u i r a bien v a duoc c au t ao b&i c a c tang. c u o i, san, cat vo sinh v a t,
Them
san ho rat he p phan bo h a n che & phi a DB. rat ph o b ien & DN Vucm.
v a D'au Be. Tai day (V;;tn Bo i, Van Ha , D~u Be) hlnh thai the m rat di;ie.
trung, mat them g ap nh ieu san ho tao r an, ke c a s an ho c anh Acropora.
Day',
la n oi t r u n g u cu a nh1eu loai nhuyen
the niur tu hai, ngao so ... h ln h
COn
th anh nen cac ba:i d a c san Van Ha , Van B~i, Ctr a Ca i. . .T h e m san h o dJiQ'c'l
hinh t ha nn trong giai doa n bien t ien Holoxen.
M ~ t them
hien ta i c o ban la
t a o n en khi rrnr c bien
ha thap hon h ie n nay khoang·
m ~ t rnai m o n do s6ng
1,5m v ao 700:-1000 narn tr tr o c,

+ D o i c a t not c la o do dong c hay v en dao ta o ne n tr en m~t them san ho ..
Ca c doi cat vo sinh v~ t nay thu o ng chi rOng dai viti chuc den va i tram met
(Hon Tharn, Hon Cat, Ho n Tai Keo ... ). Day cling IA mot da ng d ja hlnh b a :
dOc dao.
.

+ D e lta trfElu. a rno t so ang kin, g~n kin e6 t ich tu dang dja hlnh delta
trieu kieh thiroc nho v a & phia trong la ch thong (rig am ho a c h e ). Dong t rieu
tren da dir a cat vo sinh v~t va o trong ang va t ich 1\1 la i ng av cua d o toc,
dO giarn dQt ngQt (Ang Tharn, Ang Vern ... ).

21


- cA c zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
KI~U
TRAC DI1;N B O '

Cac yeu to v a, dang dja hlnh k~ tren t a p hc p TSRQPONMLKJIHGFEDCBA
v a i nhau
thanh cac kibu
trac dien ngang bu. M5i trae dien Iii k~t qua cua cac qua tr lnh b o the h ie n
vai t r o u u thl! quan tr ong hoac thu- yeu cua cac yeu to dong' luc,

+

Cae

Cae

k i~ u

k i~ t l

ber

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p h a t t r i ~n t r e n
n ~ n e ta u B i

tra e

trae

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d t~ n

phat

t r i~ n

Ba

vach

b -

Ba

vac h da vOi d6e, doc

c-

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vach

d -

Ba

h -

Ba

Cae

k i~ u

tra e

du-ng - them

tieh

Bo-

B t»

p h c it

doc
trte n

thoai

doc,

t

P lu u ,

ck:«

10m.

san

hO.

mai mo n.
tu co - bai

them

s an ho,

hoa i+ -b ai tr ieu thap,
ng{[n

< '1 n

tho ai tl ch tu tang,

vach

dung
nen

tre n

cdc

sau duai

- bai tr ieu cao h e p - bai tr ieu thap.

b a e6

d i~ n

n - De cat ell - bili

+

nen day

thoai - bai - them san ho.

d6c,

1- Bo- su6i doc,

hQ e

mai rnon - them

m on

h6a

k - Bo va ch doc drr ng , sap 10-co do i khdi
m -

h6a

rn a i rnon ,

doc dli'ng - them

da vOi doc - them

suo n doc,

Bo- suan

i-

da vOi d6c,

suo n tho a i - them

e - B a suan

men

lin

d a vOi doc hoac d6c du-ng tren

a -

d - B a vach

n g C fn

tfe h

yeU

tang

0- c h an.

dam, cuoi 0- chan.

tre n nen day bien
tra m

hQ e

f)~ ter

sau duoi
ba

10m.

ra i

cat - b ai tr ieu,

c lo c m

b e}

nlfa vao cac di;ie diern ; thanh phan v~t chat va cau tao da goc bo : vai
tro cua cae nhan t6 dOng hr c ble n : cac dang dja hrnh b o, ki~u tr~e dien bo :
d~c diem
phat
tr ien tien
h6a b e , c6 the phan
chia
b a blen V QG thanh
4 doa n di;ic tnrng.
f)oc;rn b e} th c/: n h C f t pha n bo 0- ph ia bac, DB Yuan, tir Ang Ke den hon V:;\
Gia Con. Vach hoac sir o n b o doc, th oai, ctfu ta o tir da v oi p han lap xen
vOi silie va phien silie k ha ben vfrng bo-i qua trlnh
an mon h6a ho c. Vai tr o
cua trieu lo n, s o ng nho , Ngtfn ~n mo n nhieu chb yeu, dH yeu. Thuong
gi;ip
cac b a co ngan kep , khOng doi xirrig' hoa c k hong e6 ng an, ph() bien la cac
b l l i trieu
bun bOt set thap, hiern g~p ba i cat. Them san ho h e p va phan bo
h an che. Thuo ng g~p cac kieu trac dien b a a, d, h, i. it g ap kieu m.
.
f ) o Q . n b & t h e r h a i n~m
0- phl a dOng nam (D N ). Yuan tir hon V:;\ Gili Con
tai mo m phia bac ho n Bb Lau, Suan, va ch b a d6c, doc dung cau ta o tir da

vOi u sach » dang kh6i rtft thuan l q i eho qua tr Inh an men h6a hoc ph at tr ie n,
S6ng va tr ieu deu e6 va i tro q ua n t r ong , Sinh vat b i en (san hO) da: g6p p han
quan tr ong trong vie c tao nen dja hlnh sinh v~t. Ngan
an
m o n ph at tr ien
manh, phb bi!!n cac nga n d on, d6i xtrng, sau, rOng. Hay gi;ip cac cir a th ong ,
hang IU<>nva ngtfn c() cao 2-2,5m. Phb bien am tieu san hO va vien b o va
cac vun g sari hO hlnh thai gi6ng am tieu vo ng , thuo ng' g~p cac tr~'e d ie n kieu
c, d, e, k, it g~p kieu a, b, hi6m g~p ki eu d. C6 m~t cac dang delta t r ieu, doi
c a t n6i d a o ,

22


f)oQ.n fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
b a th u b a p h a n b6 quanh cum hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
d ao Dl1u Be, CatTSRQPONMLKJIHGFEDCBA
Dua,
B ~ LAu.
Ang Tharn, Cat Co. Sucyo va vach c6 the doc tho ai h o a c d6c dung.
B<'1 va ch
DQng hrc s6ng
-duQ'c cau ta o tll' da vOi phan lap xen voi s il ic, phien. silic.
bi~n kha m anh va c6 va i tr o quan tr ong. Vai tr o sinh v~t (san hO) tao dia
hlnh Ian. Cac ng an an men c6 th~ pha t trien rat m anh hoac rat yeu tuy tll'ng
cung b o , Ph~ bien them san ho nhirng hiem g~p hlnh thai am tieu vong g ia.
Phb
Hay g~p vach s a p d~ do s6ng va tr ong lu c, vach c6 tang darn a chan.
bien cac kie u tr ac dien b e a, c, d, e , it g~p k ieu b, k, 1 va hiern g~p k ieu d.
f)oon b a th u tu a Bili Duang

Gianh. phat tr ien tr en nen tram tich D~
hI b a r o i, S o ng (khi tr ieu cao) v a tr ieu la yeu t6 dOng ll,l'c b a uu th~. Cac
dang dja hlnh bo quan
t r ong ta
de cat cu, bili triel! cao co thuc vat
ngap man, bai tr ieu thap bun cat v a bili cat. Chi g~p t.rlic dien b a k ieu h.
B a bien dang b i x6i la .
3 . D JA

M ~O

D A y BIEN

VQG

Trinh
Phung va d~ng ng hie p [3J dil xep day bien VQG Cat Ba vao phu
kieu dong bang tich tu c6 dang dia hlnh ke thua va xarn th •••.
c cua dong t rieu.
Chung toi p ha n chia chi tiet day bien VQG thanh hai to h o p dja hlnh c6 cung
nguon g6c ngoa i sinh sau :
- T O H Q 'P cA C B ~ M '; T rtca T V . Chung chiern dien ttch phan Ian day vtr e n
(31km 2 , khoang
60%) va bao g(}m ba be rn at chinh.

B ~ m < ';lt tfc h t l, L s d u t r u n g b in h 3 - 4 m c o dien ti c h khoang
7km 2, chu yeu
fJ phia narn, DN Vuan trong mOt 56 v u n g bie'n nhu Vung' ~ch, V a n TAi •.. va
mOt s6 da, hep qu anh cac dao, Be m~t n ghieng th oa. (0;002)' chu yeu theo
huang tll' DB xu6ng

TN. N6 c huybn tll' them san h o xu6ng
qua mOt suon
d6c 30°. Tai suan
d6c nay, qulin the sa n h o hien dang phar trj(~n manh.
Be
m~t co dO sau dao dOng tll' 2 - 5m va d u o c phti mOt lap tr arn tich mat set
bOt nau xarn hoa c xarn xanh. B~ mat b i chia cl1t manh b a i cac dao va cac
Iach trfing ,
Tuoi
nam

cua be m~t Ia cu6i Holoxen

gifra (Qrv2(?»,

khoang

4000 -

3000

trtro c ,

B e m < ';lt tfc h tf,l s d u 6 - 1 r m c6 dien tich k hoang 5km2, phan bt6 chu y6u
a Tung Lon Quay, Ce a Cal, Van BOi, Cua Tung R o . ha n chi! tr ong cac
vl)ng cua d ao D a u B~ v a mOt d a i he p xung quanh cac dao, Ranh
giai tr e n
vo i b~ m~t thu nhat thir ong tao r a vac h d6e 20-30°.
tr en do phat tr ie n cac
loai san ho ta o ran. B! mat d6c tho ai (0,002), cfing c6 no i to i 0,005 (v ie n

xung quanh c ac d a o va 0 Cua Tung R o ). Day la be m1:1tcua c a c lung
caxto
bi lap day (Cua Cai] hay cac n6n phorig vat truae
cua cac song s u 6 i c~
(V~n BOi, Cua Tung R o ) phu tr en b e m~t luen nay IA set bot nau xam,
Be m~t dugc

thanh

ta

o v ao cu6i

Holoxen

srrrn (QIV1c).

B ~ m < ';lt ttc h t l , l s d n 12 - 20m c6 d i en tieh Ian nhat kh oang
19 k m", phan
b6 chu y~u tr ong vjnh Lan H~ va mOt da i hep
a dOng va DN: Dau Be.
Trong vjnh Lan Ha , a ranh g ic i phia dong va tay v , a ; be m~t thtr hai b! m~t
nghieng
thcai (0,005) dan vao t rung tam, r anh giai b a ta:y doc hen (0,01),
hii!m g~p san ho pha t trien. ( y phia b ac va phia narn vinh be m~t lai thoai

23


dan tir gifra vjnh ve hai phia. (] dO sau 12-14m

tbn fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
t~ i 2 be mat kha phang
(g6e d6e g an b~ng 0°), chung chuyen tiep tir tir hoac mot vach nghieng tho aiTSRQPONML
v a i dja hinh xung quanh. Day vjnh ciing hi cac Iach, chi a d.t a m ite
(0 .0 0 7 )
dO ysu ho ac cac go d6ng noi cao 1 - 2m lam
phirc tap. ()' ph ia nam va DN
d(lo Dau Be ch ung la hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
i chia clit rnanh
ho n b a i cac d a o noi, da ngarn va cac
Iach tr ilng . Phu tren he m?t nay Ia set b e t nau xarn,

Be mat Ia canh dbng caxto bi ngap c hlm, c6 lien quan v a i sg heat dong'
cua s ong, su6i cb tru o c bi en ti en, vi v ay be mat duo c hlnh th anh va o gifra
Holoxen
s o m (Q 1 y 1b).
- TO

HOOP CAC L~CH

K~

THU A - xAM

THl,TC DO

DONG

TRI~U

DAy la to ho p cac dang dja hlnh tuyen duoc ke thira bo i c ac qua trinh
xam thu c luc dia tr urrc bien tien. Nay dong trieu dang hoat dOng xarn th uc ,
Tuy h ln h thai cac Iach da bien doi nhieu xong nhtrng net c o ban ve hlnh
dang cua c h u n g van con gifr d u o c ..
c it vao dO sa u c a sa c u a ca c Iach
Can
nguyen tac phan cap Jach song chung tOi phan

khi hOi Iuu vo i nhau va theo
ra 6 cap :

C a p I: La cap nh e nhat,
Mgc c c so dat den dO sau 1,5 - 2,Om dll&i
OmHD. T r ac d ie n n g a n g h lnh chtr «V» nhung
hie n nay nhieu n o i d a bj qua
tr lnh tich tu hay qulin the san ho lam bien doi, san phang ,
C a p 2 : Duoc thanh ta o tir sg 1 1 0 i tl} c u a 2 lach cap 1. Mgc c o sa dat den
dO sau 3 - 3,5m. Tr a c dien nga ng c6 h rn h chLi «V D thoai h e n , Day nay cling
hi tram tfc h set .hOt nau xarn phu tr en ne n cling hi san lap va th oa i hon
nhieu, C6 the glj,p chting a Tung Chang, Tung Gtfu, Tung Ro ...
C a p 3: Du oc.htnh
t ha nh do sg hOi l u u hai Iach cap 2. M g c
hlnh chfr « U» Chung
dat ta i dO s au 6 - 7m. Tr ac di¢n ngang
Cua Cai, Tung Gau, Tung Ro v a a phia DN, TB dao Dau Be.

so c6 the
phan b6 "

co

ta o do sg hOi Itru 2 lach cap 3. Mgc c o so d a t ta '
ca p 4: DllQ'C thanh
dO sau 12 - 13m. Trac d ien ngang c6 hlnh chLi « U» tho ai h o n , Chung phan
b6 a cua Tung Gffu, Tung Ro, Tung Ng6n, Tung LQ'n Quay ...
C a p 5 : Thuo c ve cap nay
trong
pharn
vi VUCYn c6 La ch Ng an, Lach
Dl:1u XU6i, Iach phia
narn vjnh Co ng Hip va Ia ch phia bac da o Dau Be.
Tr ac dien ngang
c6 hlnh chtt ({U JJ tho a i, Muc co sa c6 the dat ta i dO sau
20 - 22m Day lach tich tu set bot n au xarn , xa m xanh ,
• .

duoc hlnh tha nh do lien ket 2 lac h cap
ca p 6 : La ctfp Ian nh at Y u a n .
5. Mgc c o sa c6 the dat to i dO s au 35 - 40m. Tr ac dien ngang .co dang hlnh
chtr « U n , Trong p h a m v i Y u a n cap 6 diroc the hien 1 f t La ch Va n, Day dang
duo c ti ch tu ca c tram t ich cat vo sinh vat, bun set.

4. LJCH
d~n

sir

PHAT

Vung bien VQG Cat

gan cu6i Pleixroxen.

TRIEN

DJA HINH

Ba da tung

duQ'c noi cao fu cu6i

d ai Co sinh

cho

Vao thoi gian Pleixtoxen
che dO Iuc d ja chiern uu t h s a Yuan.
Qua
tr lnh caxto
luc dja d§ t ao ra cac da ag dja h lnh nh ir thung lung ca x to , canh
dbng cax to va met he th6ng song su6i cb kha day d~e chia cat va bao quanh
dja phan Vuon.


Cu6i
d a n g cao

Ple ixt o xen do anh
d an,

huo-ng cua

do t tan bang'

h a Ian

cu6i,

mu c bien hgfedcbaZYXWV

KhoAng gifra Ho loxen sorn nucc bien d§ dang tr an ng ap vjnh Lan H~.
Cu6i Ho lo xen sum (kh oang 7000 narn tr u o c] muc bien dang eao chi con thap
hon hien nay 5 - 6 rn, cac khu vue ven b e cu a VQG b at dau bi bie n tr an
T a i. Cac tung
ang Ian c6 ngubn
vao chia c~t v a t a o ra nhi eu dao nh6 tach TSRQPONMLKJIHGFEDCBA
g6e thung lung cax t o blH dau bi ng ap n u o c bien. Cac qua trlnh b o bat d au
xfty ra m anh me du6'i t ac do ng cua ca c n han t6 do ng Iuc bien. Den giiia
Ho loxen gifra (kho a ng 4500 narn truuc)
rnuc bi en dang cao cue da i, eaohan
hie n nay 5 -6 m t ao ra cac v~t ha e~ barn tr en vach, ng an an rno n ho a hoc,
cac hang dong eao 3 - 4 m v a 5 - 6 m. Vao thai gian nay sa n he> p ha t tr ien
cue thinh tao ne n cac am tieu sat b o, vien qua nh bo dao, vien bo cac tung,
arig va ta o nen cac vung san he> (coral lagoon). Mt,rc bien luc ay dang cao
lam ng$p ca nhtmg ht> hien nay narn kin gifra nui v a san he> rao r an da p ha t
tr ien vien quanh b a hb (khu Van Ha).
Sau do m uc bien ha thap dan v a da t rrnrc cue t ieu, thap ho n hien
khoang
3 - 4 m vao cu6i Holoxen
giua (3000 - 4000 narn trtrrrc}.
Ti~p sau mu c bien dang cao dan

rnuc bien h i e n nay v a o dau Holoxen
bien dang cao tr o la i dii tang cuong
he> pha t tr i en.

nay

tro- lai v a dat ctrc da i 3,5m cao han
m uon (khoang
3000 narn truce).
Mt,re
qua trlnh b o v a ta o di eu kien cho san

Vao khoang 2000 - 3000 n arn t ru o c rmrc b.en la i h a rhap. Trong
qua
r Inh h a, rrnrc bien ngiIng nghi, on d jn h tarn thai a dO cao 2 m - 2.5m ta o ra
hang loat ng an an mon h6a h oc, cac them bie n. Ml,Jc bien ti~p t uc ha thap fedcbaZYXWVUTSRQP
to i
rmr c tha p ho n hi¢n nay khoang
1,5m va o 700 -1000
narn [4,5] t a o n e n be mi;it
them san he> thoai h o a eao trung b lnh 0.51m/Om HD TiI do d~n nay, rrnrc
bien dang ca o d a n. St,r dang eao rmr c bien da da:n d~n mOt 10'.1t hie u ung.
Hoa t dOng cua t huy t r i e u duo c tang cu ong da duy t r t v a xa rn t hir c sau cac
luong lach baa quanh d a o Cat Ba. Qua tr Inh an rno n hoa hoc cu a nu o c bien
duQ'c dong tr ie u va s6ng tang cu o ng them Bien dO tr i eu Ian mo- r ong dO cao
cua ngan. Hoat d o ng cua thuy tr ie u con ta o ne n ca c b a i tr ieu tich tu lap
day m¢t s6 ang, vun g nua kin, gan kin va bun phu tr en mat them san he>tho a i
h6a
Hoa t dong cu a sorig cfing tang nen nhi eu n a i xay r a sap v a ch, So ng
pha My b o va tao n e n c ac dam, tang, them mai rn on (] ch an vach. Di;ic b ie t

s6ng da ta o nen c ac ba:i cat nho v6 voi sinh v ~ t tr e n m~t them sa n ho (] sat
b a c a c cung 16m. Hie n tai die ba:i deu c6 xu huang
tang tru cng ve klch
thu oc va chieu cao. a rno t s6 no i san ht> ta o r a n dang tai sinh tr en mi;it them
thoai h6a. (; su o n d6c th oa i sau 3 - 4m am t ie u sa n he> dang p hat tr ie n kha
m anh, a dt) s a u Ian h a n do xarn thuc cua dong tr-i eu v a dong bun cat nen
s an he> kern ph at trren.

t

K~T
Dja
dao bao
hiern c6
Dja
tri~n tre

LU~N

h lnh vung bien VQG h~t s u e da
g orn vung eaxta
ven b a bj ngap
t ren th~ g io i,
hl nh day Yuan con m a ng n h i eu
n can n hu cac lung caxto, canh

dang, phirc tap
h iern tro- v a d o c
ch lrn vo i nh i e u c anh quan d?c sac
net d ac trung cua vu ng cax to phat

dong caxro va rna ng luo i song su6i

25

/


-cb nay da b ie n thanh cac tung, ang , la ch ..hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
song dja h lnh TSRQPONMLKJIHGFEDCBA
b a Ia i b] bien dbi
kh a nhanh b o i tac do ng cua e ac y~u t6 dong hr c bien n htr rnrrrc bien, t rieu,
s6ng, sinh vat tr o ng Ihn bien t ien sau bang ha l an cu6i.
i

Dja hi nh do sinh vat ta o r a (dljc bie t la san he chiern mot dien tich dang
ke fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
a vung bien cua Vtr c n . Day c iin g la mot dang dja hlnh am ti eu dOc dao
co ljch Slr g an li~n vo i bien t ien Holo xen ,
Cac d?c diem dfu tao da g6e bo, tinh
lap .•. c o anh huang
dang ke d~n S1,l' phat

T AI LI~U

1. Shepard

F.P.

f)ia

chat

THAM

NXB

b ie n ,

pharr la p , u6n nep, g6c earn cua cac
tr ie n cua bo d a o .

KHAo

Nhi edra », 1971 (Ti€ng

«

2. Nguyen
Thanh So n v a Trinh Phung. C de k i~ u
tai Hoi nghj kho a hoc bien IAn thu nhat,
3. Trinh Phung va nnk. B !)c c l i~m tr a m tfc h Q uang
Nfnh - H d i P h o n g . Bao cao hIU
Due Thanh va n .k. B (1 c clfem
p hat h.e n m o i ve khao cb h o c
:5. Trhn Drr c Thanh va nnk. B ia c h { [ t
Nom, 1985. De t a i 48-06-14.
4. Tr an

c lta

ba

b i~ n

V i~ t

Nha

Trang,

c lio

h ln h

trfr

ch{[t

Nga).
Bao ca o

N om .

1978.
vung

b i~ n

ven

1975.

tai TTNCBHP,

elf

khu

bO o

C ai B e o , «Nhfrng

chi

1984».
-

f)ia mc o d d i v e n .b ie n p h C a b a c V i~ t
Ltru trfr TTNCBHP,
1985.

-6. Zenkovich
V.P. T r ~ n b a b ie n rueo c V i~ t N o m
D an chri C O ny
h o a , NXB
« Hai dirong h oc », 1963. Quyen 3, t? P III (Ti~ng Nga).
7. Zenkovich V.P. B O o T h a i B ln h D L r a n g , NXB « Nauka »,1967 (Ti€ng Nga).

SUMMARY
SOME

GEOMORPHOLOGICAL

FEATURES
D in h

T he

m a r in e

b y Holocene
s u c c e s s io n

of

processes

(tid e ,

H o lo c e n e .
d iv id e d
p r o fil

s u r fa c e s ,
and

of

C a tb a

sea

p a r c e ls

w ith

10

r e lie f

H uy,

r e lie f

and

by

H~ L~CH

of

tid a l

TRIEU

N a tio n a l
s y s te m

P ark

due

Thanh
subm erged

to h a v in g

m a r in e

b u fd in g ,
th e

coast

e le m e n ts ,

w ith

is d is tin g u is h e d

and

th e

d y n a m ic

.• .)
of

d u r in g
park

12

is

c o a s ta l

6 degrees.

They

in to

a r e o ld

.3 a c c u m u la tiv e

s tr e a m s

succeeded

c u r r e n t.

6

OAI BO BIEN HAl PHONG - QUANG

T rn «

£Juc

T h { ln h ,

N guy@ n

Lac h tr ieu da ng dja hlnh
phia t ay vinh Ba c bOo Chung

26

D uc

th e

reef

ty p e ,

PARK

la n d fo r m
area

to

coral

erosion

fo r m s

T ran

is a n K a r s tic

c o m b in in g

e r o s io n ,

c h e m ic a l

Van

NATIONAL

,
b o tto m

cut by channel

e r o s io n e ti

th e

CATBA

c o m p le x

processes

c h e m ic a l
to

P a ,.k

a very

is

k a r s tic

w ave,

4

n a tio n a l

It

m a in la n d

B e lo n g in g

in to
ty p e s .

The

area

tr a n s g r e s s io n .

OF

B in h
H fru

V l1 n

YEN
Ht!Y,

C ir

xarn thuc tie u bieu v a dljc trung a dai b a bien
Ia d 6 i tuo ng thuo ng xuyen ph ai d e cap d~n