Kết quả bước đầu nghiên cứu tốc độ lắng đọng và tuổi trầm tích hiện đại vùng cửa sông bạch đằng bằng phương pháp đồng vị phóng xạ 210pb và137cs

V I~N B A N LA M K H O A H Q C
V IEN
D IA CH A T
••

vA C O N G N G H ~

V IeT N A M

vA D IA
V A T LV B IEN
••

V IETN A M A C A D EM Y O F SC IEN C E A N D TEC H N O LO G Y
IN STITU TE O F M A R IN E G EO LO G Y A N D G EO PH Y SIC S

TU Y E

T-PB '

CAOKHO

H Q I N G H f K H O A H Q C B fA clIA T B IEN ToA N

HA

NQI - ~

OC
•

ouoc

LA N TH U H A l

LO N G , 10-12/10/2013

PR O C EED IN G S
TH E SECO N D N A TIO N A L SCIEN TIFIC CO N FEREN CE O N M A RIN E G EO LO G Y
H A N O I-H A LO N G , 10-12 O CTO BER, 2013


l

14.

Trin

A nh Tu~n, Phung

V an Phach.

V ien dful chirng cir v~ dia m ao h6 tro

198

xac dinh ranh gioi vo luc dia - dai dirong tren B iSn D ong V iet N am .
15.

Le D inh

N am , Le

Phuong,

Trin

D uc A n, N guyin

X uan Lvi, Trin

Th~ Ti~p, Ph an D ong

A nh Tuan, Trin

va

Ph a,

H oang Y ~n, D uong

Le

207

Tu~n

N goc, M Q t s6 d?c diSm dia m ao khu V \ICTruong Sa va Tir C hinh - V iing M ay.
16.

B ili V an V U 'Q 'Ilg,Trin

D uc Th~nh, D ~ng H oai N hon. D ?c diSm hinh thai dia

219

hinh ran san ho quan dao Truong Sa.
17.

Trin

X uan

A nh Tu~n,

Lvi, N guyin

Th~ Ti~p, Ph an D ong Ph a, Le D inh N am , Trin

V ii Le Phuong,

Trin

H oang

Y ~n, Pham

229

V i~t H A ng, D uong

Tu~n N goc, D ?c diem dia hinh dia m ao day bien N am Trung B Q .
18.

V ii V an Phai, D uong

Tu~n N goc, LU 'u Thanh

C hung.

N hfm g bang chirng

243

dia m ao v~ S\I thay d6i m ire m roc bien tren dai be bien N am B Q trong giai dean
tir H olocen gifra d€n nay.
19.

V O Thjnh, Phan D ong Pha, N guyin
Tu~n, Le D inh N am , Trin

X uan

X uan H uyen,
Lvi, Trin

V ii V an Ph ai, Tang Phuc

H oang

Y ~n,

va

251

Le Phuong,

D uong Tu~n N goc, C ac kiSu 00 bien khu V \ICPhu Y en - K hanh H oa va vfuI d~
du bao xu th€ bien dQ ng bo bien trong b6i canh m \IC m roc bien dang.
20.

Pham

B a Trung.

D ac diem dia hinh day va trfun tich tfuIg m at vung bien ven

260

bo tinh B inh D inh,
21.

N guyin

D ang

Tuc,

Phan

Trong

Trinh,

B ili V an

Thom ,

N guyin

V an

271

H U 'O ng, N go V an Liem , V ~ cac them biSn va tu6i san he doc bo biSn K hanh
H oa - B inh Thuan.
22.

V ii D uy V inh, B ui V an V U 'Q 'D g.A nh huang cua m Q t s6 y€u t6 khi nrong hai

285

van d€n bien dQ ng dia hinh day vung ven bo chau th6 Song H 6ng.
23.

V ii V an Phai, D uong

Tu~n N gQ c, LU 'u Thanh

If thong

D inh N am . N ghien ciru dia m ao phuc vu quan
24.

B ui V an V U 'Q 'Ilg,Liu Zhi Fei, Trin
H ub, Tuo Shouting,

D uc Th~nh,

D ~ng H oai N hon, N guyin

D inh V an H uy, N guyin

Trung,

D inh K hang.

V ii Le Phuong,

Le

297

nhat doi bo bien.

Trin

D inh Lan, C hi-A n

V an Q uan, N guyin

306

D ic V ~,

K €t qua biroc dau nghien ciru t6c dQ

lfutg dong va tu6i tram tich hien dai vung cira song B ach D fu1g bang phirong
phap d6ng vi ph6ng xa 210pb va 137C S.
25.

N guyin

Ti~n H ai, Ivanova

tram tich
Lk.D A 3.
26.

H oang

a khu

Trung

Y e.D , N guyin

H tru

Cu. D ?c

diem m oi tnrong

V \IC cira D a R ang, Tuy H oa (Phu Y en) qua t~p m §:u

D u, Tim Jennerjahn,

A ndreas

K unzm ann.

316

16 khoan

Tac dQ ng nguon

327

v~t ch~t song len lang dong trfun tich va y€u t6 sinh dia h6a vung bien ven bo
vinh N ha Trang - K hanh H oa.
27.

N guyin
H oang

Trung

Thanh,

Phung

V an Long, Pham

V an Phach, Le D uc A nh, Pham

Tu~n A nh,

342

Q uac H i~p. D anh gia anh huang phan toa phu sa

cua song M e C ong len them I\lC dia k€ c~

bang ham hrong t6ng cacbon htru

co (TO C ) va cacbonat trong tram tich.
28.

Phi Truong

Thanh, Trin

H a, N guyin

Th] D ung, Trin

lira bun,
6

Tu~n D iing, N guy~n Q uang M inh, N guyin

Th] H ai

Th] H A ng M inh, Ton V an Son. T6ng quan v~ nui

354


H6i nghi Khoa hoc Dia chdt biin toan quoc ldn tM II zyxwvu

KET QuA

BUOC

DAu NGHIEN

ciru TOC

DQ LANG

VA TUOI TRAM ZYXWVUTSRQPONMLKJIHGFEDCBA
'r t c n HI¥N D~I vUNG CUA SONG B~CH
PHUONG

PHAp

DONG

IBili Van VU'c;mg, 2Liu Zhi Fei, ITdn

VI PHONG

Du'c Th~nh,

~

ITdn

DQNG
DANG BANG

210Pb va 137Cs

Dinh Lan, 2Chi-An Hub,

ID~ng Hoai Nhon, INguy~n Van Quan, INguy~n D~c V~,

2Tuo Shouting,

IDinh Van Huy, INguy~n Dinh Khang

"Vien Tai nguyen va Moi truong bidn - VAST
2 7ruc'mg

Dai hoc D6ng

tt. ThuongLKJIHGFEDCBA
H a i, Trung Qu6c

E-mail:

TOM TAT:

Vimg cua song Bach DJng la mot cua song hinh phlu 11m va quan trong thir
Nam (sau

cua

song D6ng Nai), nai co cang Hai

Phong

va cang nutrc

Lach

SQU

2 &

trong

H uyen

tuong lai. Vimg cua song nay chica dung tai nguyen thien nhien da dang va phong

Vi¢t

phu,

lien

quan ddn din h¢ thong lach tri€u va cac h¢ sinh thai nhu rung ngtjp mdn, bdi trieu v. v. Trdm
tich va dia hinh (fling dong tram tich, sa b6i luong lach) vimg cua song bidn d6i manh co anh
huong ddn gia tri tai nguyen va cac hoat d6ng kinh
kit qua nghien

CUu

d dgc

biet la cang bidn. Bai bao trinh bay

buac dau vi t6c d6 lling dong, tu6i tram tich hien dai cua tram tich vung

cua song Bach DJng. T6c d6 !&ng dong tram tich nhdn duac tir mat clit

210 Pb

va

137CS

bien

2

d6ng tir 0,69-0,97 cm/ndm, kh6i IU(1ngtram tich tich tu tir 0,5198 ddn 0,8045 (g.cm- .yr- l).
210 Pb

duac sit dung cho tinh toan tu6i tram tich hien dai trong vong 100 ndm,

137CS

dung dd

2l

xac nhdn d6c ldp kdt qua tu6i tram tich nhdn duac tir OPb.

T V ' KHOA:

T6c dQ l~ng dong, tu6i, Bach Dang, 210Pb, 137CS

D~TvANDE
Tang quan vin d~ nghien

cuu

Vao nam 1963, Goldberg

IAn dAu tien d~ xuat v~ sir mAt thang bang gifra 210Pb va

226Ra co th~ phuc vu xac dinh tu6i trAm tich hien dai, Ciing trong nam do, ong da ap dung
thanh cong phirong phap phong xa 210Pb co ban chu ky phan ra la 22 nam d~ xac dinh tu6i
tram tich cua cac tang bang

a Greenland

[14]. D€n nay, phirong phap nay dll duoc ap dung va

ph6 bien rong rai d~ dinh tu6i, t6c dQ l~ng dong trAm tich cho cac thuy

V\fC:

h6 [17], [36], bi~n

[18], [29] va dAm pha [2]. Ben canh do 137CSciing duoc sir dung d6ng hanh, kiem chirng dQc
l~p so voi 210Pb d~ tinh to an tuoi, t6c dQ lang dQng trAm tich. K€t qua tinh toan v~ tu6i, t6c d9
l~ng dong tram tich la

C (J

sa quan

trong nghien ciru anh huang cua qua trinh tram tich den qua

trinh xoi lo; b6i tu, gia tang dQ due,

C (J

ch~ v~n chuyen tram tich tic nguon d~n b6n [6], [10],

[11] va cac tac dQng toi cac h~ sinh thai, vi du nhu h~ sinh thai co bi~n va ran san ho.
306

tu« ban Dja ehdt va Tai nguyen, Khodng san biin

H9i nghi Khoa hoc Dia chat bidn toan qu6e tdn thU II

Vung cira song Bach D~ng (VCSBD)

la mot cira song hinh ph@u IOn va quan trong thir

2 Vi~t Nam (sau cira song D6ng Nai), noi co cang Hai Phong va cangZYXWVUTSRQPONMLKJIHGFEDCBA
m r o c sau Lach Huyen
trong nrong lai. Day la vung cira song chira dung tai nguyen thien nhien da dang va phong
phu lien quan den h~ thong lach tri~u va cac h~ sinh thai nhu nrng ngap man, bai trieu v.v.
Trftm tich va dia hinh va (lang dong trftm tich, sa b6i luong lach) vung cira song bien d6i
manh co anh huang

den gia tri tai nguyen va cac hoat dong kinh te d?c biet la cang bien, do

d6 thu hut m6i quan tam cua cac nha khoa hoc nhir: tien hoa chau th6, dong lire hoc, trftm tich
hoc, dia mao hoc, v~n chuyen trftm tich, Nghien ciru v~ tu6i, t6c dQ l~ng dong trftm tich hien
dai

a vung

cira song nay v~n chira duoc quan tam. Bai viet nay cung dp

dfr lieu, thao luan v~

tu6i va t6c dQ I~ng dong tram tich hien dai vung cira song Bach D~ng dira tren tinh toan nang
luong phong xa cua 210Pb va 137Cs elOPb, 137CsradionucIides)

tai mot s6 cQt khoan 6ng ph6ng

trftm tich tftng mat.

TAngMLKJIHGFEDCBA
q u a n v~ di~u ki~n t v nhien vimg cua song Bach J)~ng
V ung cira song co c~u true mra kin, co quan dao Cat Ba chan phia dong. bac, ban dao
D6 San chan phia tay nam va con co h~ dao cat Phu Long, Cat Ba, Dinh Vii chan ph fa bien

a

dong nam. Cac nhanh song chinh tren vung cira song la Yen Lap, Bach D~ng, C~m va Lach
Tray (hinh 1).

Dia hinh VCSBD da dang va phirc tap, g6m nhi~u kieu, dang dia hinh co nguon g6c
khac nhau

va

co th~ duoc chia thanh 4 nhorn: Dia hinh d6i va nui thap, d6ng bang khong ngap

trieu, d6ng bang ngap tri~u tv nhien va dia hinh bo ngftm - luong lach ngap mroc thirong
xuyen [32]. H ~ th6ng lach trieu phat tri~n day d?c va thuoc hai nhom. Nhorn thir nh~t phat
tri~n ke thira nr nhfmg long song cii diroc mo rong va dao sau long nho xam nhap cua dong
tri~u b~ mat va day (Lach Huyen, Nam Trieu, Cai Trap v.v.). Chung rong toi 2-3 km, sau toi
10-15 m va keo ngam ra phia bi~n chuc km. Chung bao va chia cac khu bai trieu thanh cac
dao biet I~p, rong toi chuc krrr'. Nhom thir hai g6m nhieu cap, hinh thanh do heat dong cua
dong trieu tftng mat, Chung phan dt

cac dao bai trieu thanh nhieu manh khong tach roi nhau.

Cac bai trieu cao chiem 70% dien tich, dQ cao tuyet d6i 0-1 m [32].

Day la vung co che dQ nhat trieu di~n hinh voi hftu h~t s6 ngay trong thang la nh~t
trieu, dQ IOn tri~u cue dai 4 m, t6c dQ dong trieu trung binh 30-50 cm/s, cue dai toi
cm/s. Dong tri~u thuan nghich, eIIip tri~u r~t dep. Kh6i mroc VCSBD

1 5 0 -1 8 0

co ban IQ'va IQ'nhat vao

mua rmra, lo va IQ'man vao mua kho.
Dong chay co thanh phan dong tri~u quyet dinh, nen co tinh thuan nghich trong ngay,
phu thuoc vao dia hinh bo, huong bo, luong lach va cira song. Dong chay manh vao cac thang
6, 7, 12, 1, y~u vao cac thang 3, 4, 8, 9 va manh nhat khi mire mroc dao dong len-xuong
ngang qua mire trieu trung binh. T6c dQ dong trong khoang r~t rQng tir 0,1-1,8 m/s, trung binh
10-30 cm/s. T6c dQ dong chay xuong IOn hon dong chay len: Tai cira Nam Trieu, t6c dQ dong
chay xuong cue dai 90 cm/s, t6c dQ len cue dai la 60 cm/s.
Do anh huang

cua dia hinh,

song bi~n n6i chung

O,75m, tnr nhfmg dip bao, tftn xu~t lang s6ng dat khoang

tu« ban Dia chat

khong

Ian dQ, cao trung

20%. Trong

binh

hftu h~t cac thang,

va Tai nguyen,LKJIHGFEDCBA
K h o d n g san biin zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
307


H(Ji nghi Khoa h9C Dia chdt biin toan quoc ldn thii II zyxwv

dQ cao song Ion nhat thuong 2-3 m, song bao dat 4-5 m,

C\l'C

dl;ll'5,6 m. Vao mua dong, tir

thang 9 d~n thang 2 nam sau, song co dQ cao trung binh tir 0,5-0,75 m, thinh hanh huang
dong voi tan xuat 34% va dong bac voi tan xuat 14%. Vao mua he, tir thang 3 d~n thang 8,

v c i tan x u s t 27% va
dQ cao song trung binh 0,7-0,9 m, song thinh hanh huang dong nam ZYXWVUTSRQPONMLKJIHG

huang nam voi tan xuat 22%. Vao cac thang chuyen tiep 4 va 10, song huang dong va
dong nam iru the.

I. TAl LI~U vA PHUONG PHAp NGHIEN

CUu

1.1. Tili Ii~u

°

Bai viSt sir dung 2 cQt khoan voi mil hieu HP08 va HP 1 LKJIHGFEDCBA
a dQ sau Ian hrot la 24 m va
10m so voi 0 m hai d6 (HD). ChiSu dai cQt khoan HP08 la 65 em va HP 10 la 90 em. Hai cQt
khoan diroc thu trong chuyen khao sat chung

g ifr a

Vien Tai nguyen va Moi tnrong bien

(IMER), Vi~t Nam va Phong thi nghiem Trong di~m Quoc gia Dia chftt bi~n (SKLMG), Dai
hoc Tongji, Thuong Hai, Trung Quoc thang 5 nam 2011 (hinh 1).
~-==----===~~~~~~r.nnr~~~----------~~~~rr~7>rJ~~~'~
00·

C H U G IA I

00"

-------sDuong
V i tr i c o t

o

km

@
sou

d6ng

(m )

khoan

5

10

,/

","s-

)

...
40'

~~

V.;,.secBd
107°

107°00· E

Hinh 1: Sa a 6 vung cua song Bach DJng

va vi tri

lJ khoan HP08

O'E

va HP 10

1.2. Phuong phap
12.1. Phtin tich phong

X{l

bang tia phJ gama

Theo dQ sau, cQt khoan dircc chia thanh cac mfiu, m6i mfiu img voi 2 cm. S6 mfiu nay
duoc phan tich 210Pb va 137Cs b~ng tia ph6 gama (Analysis of radionuc1ides by y 308

tu« ban Dia chat

va Tai nguyen,

Khodng sdn biin


H9i nghi Khoa h9C Dia chdt biin toan qu6c ldn thu II

spectrometry),

theo tieu chuAn 327 va 375 [30] cua Co quan Nang hrong Nguyen

tir Quoc t~

(IAEA), s6 m&u d~m tren may do GMX. Thai gian d~m m&u dao dl)ng nr vai gio d~n vai ngay
tai Vi~n Khoa hoc Trai Dit, Vi~n Han lam Sinica, Dai B~c, Dai Loan.

1.2.2. Phuong phdp xdc dinlt tac d~ !ting d!Jng tram tich
T6c d9 l~ng dong trim
137CSdutheo d9 sau (excess

tich (cm.yr')

210-Pb

hay 210Pbex, excess

tich. 137 -CSdu xam nhap vao trong trim
may dien nguyen

duoc tinh toan tir d6ng vi phong

tich do cac

137-Cs hay 137CSex)trong lap trim

VI,1

tir [6], [14], [15], [21], [28]. Trong

xa 210Pb va

thir vii khi hat nhan va sir c6 nha

nghien

diroc phan tich 137Cs (voi thai gian d~m dai) va liy nam

ciru nay cac m&u trim

tich

1950 la thai gian diu tien xuit

hien 137CStren vung bien [6], [10], [11]. T6c dl) l~ng dong trim

tich tinh theo t6c dl) phan

ra cua 137Cs ky hieu la SCs-137tinh theoZYXWVUTSRQPONMLKJIHGFEDCBA
c c n g thirc: SCs-137=Z/(T o -1950).
Trong

do Z, la

137Cs sir xam nhap theo dl) sau, To la thai diem thu m&u. T6c d9 l~ng dong trim

tich tinh

theo t6c d9 phan ra cua 210Pb ky hieu la SPb-210diroc tinh theo cong thirc SPb-210= - A 1m,
voi "Ala h~ng s6 phan ra cua 210Pb (0.03114y-I).

1.2.3. Kllai luirng tram ticb tich tl}
Kh6i

hrong

l~ng dong

210Pbdu tai dl) sau z bit

trim

tich/don

ky cua lap trim

vi dien tich (g crniyr')

duoc

tinh tir theo

tich eIOPbxs(z») [3]: Ln21OPbxs(z)-Ln210Pbxs(o)=(-

A210m-I)W. Trong do: Dan vi kh6i luong tich tu trim tich diroc tinh bang kh6i hrong trim
tich tich tu kho, co don vi tinh (g.crn") w la quan h~ vo'i thai gian lang dong trim
duoc

di€n

ta bang

cong

thirc

t=W.fl

(f la hru

luong

tich

tu trim

tich

tich va

g.cmi.yr').

In210Pbxs(z)co d6 thi ngiroc voi kh6i luong tich tu tren mot don vi dien tich; w: k~t qua cua
mat c~t 210Pb la tuyen tinh va goc d6c la: -"A21ofl.

12.4.

Mo

hlnh tinh tugi tram tich

SiI dung 210Pb d~ xac dinh tu6i trim

tich la mot phuong

phap

ph6 bi~n va quan

trong hien nay. Dua vao d6ng vi phong xa cua 210Pb, co th~ xac dinh diroc tu6i trim
hien dai trong vong

150 nam. Trong trim

tich t6n tai 2 loai 210Pb: "supported

san xuit tai ch6 boi qua trinh phan ra cua 226Ra va excess
quyen. Y nghia d9 phong

xa (activity)

tich

210Pb" diroc

210PbelOPbex) nhan diroc tir khi

cua 210Pb pharr b6 theo d9 sau nhan duoc

rieng do

qua trinh phan ra theo lu~t ham s6 mii (hoac tuyen tinh n~u chung ta ve sa d6 logarit s6 tu
nhien). Tuy nhien gia tri n~n phu thuoc hoac l~ng dong trim
tri xac dinh hoacbien

tich va 210Pb phan b6 d~n vi

d6i qua thai gian. Do vay, hrong 210Pbex bang hrong 210Pb t6ng tnr

di luong 210Pb diroc san xuat tai ch6.
Co 2 me hinh tinh toan cho 210Pb d~ xac dinh tu6i trim
hi: CRS (Constant

Rate of Supply)

va CIC (Constant

Initial

tich diroc dung ph6 bien do
Concentration)

[14] va tiep

tuc duoc phat trien boi [25]. Tu6i trim tich diroc tinh bang me hinh CRS (constant
210Pb supply)

rate of

[25]:

t=l/s

va

In {A (O)IA (x)}

t u « ponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
ban Dia chdl
Tal nguyen, K h o a n g san biin zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
309


H9i nghi Khoa h9C Dia chat biin toan qu6c tdn thu 11

Trong do: A(O) thS hien hrong 210Pb du tren m~t tram tich;
A(x) thS hien 210Pb dir tai dQ sau (x);

A la hang s6 phan ra cua 210Pb (0.03114i1);
t la thai gian l~ng dong tr~m tich (tuci, nam).
SU dung 137CSdS kiem tra dQc l~p voi nam 1950 la thai gian b~t d~u xu~t hien 137CS
trong tram tich thuy V\l"C.

II.ZYXWVUTSRQPONMLKJIHGFEDCBA
K E T Q u A v A T H A o LU~N
11.1. K~t qua
T6c dQ va khoi hrong tich tu tram tich duoc xac dinh tir phong xa 210Pb va 137CScho
d6ng. T6c dQ lang dong tram tich tai vi tri HP08 tir 0,82 cm/nam dSn 0,97
2
2

cm/nam, kh6i hrong tich tu/l cm la 0,8045 glcm /nam va tuong irng tai cQt khoan HPI0 la
2
0,69 dSn 0,75 crn/nam va 0,5198 glcm /nam (bang 1).

gia tri nrong

Bang 1: T6c

tJ (J

tcing dong trdm tich (em/nom); kh6i lu a n g tich t1;-l/di¢n tich g/cm2/niim)

Kh8i hreng tich

T8c dQ ling d(}ng tr~m tich (cm/nam) tir dAng vi phong

CQt
khoan

t\l/di~n tich

x~

210

(g/Cm2/nam)

137CS

Pb

HP08

0,82

0,97

0,8045

HPlO

0,69

0,75

0,5198

V oi 2

vi

tri CQt khoan, can cu phan tich phong xa, tu6i tr~m tich cho cQt khoan duoc

xac dinh tir nam 1910 dSn 2011, khoang

100 nam (hinh 2).

11.2. Thao lu~n

IL2.J.D{ic iliim liing dong tram tich VCSBD

°

Tir kSt qua tinh toan t6c dQ tram tich cua 2 cQt khoan HP08 va HP 1 cho thay: t6c dQ l~ng
dong trAm tich tai VCSBD tang dAn theo huang ra biSn: Tai cQt khoan HPI0, t6c dQ l~ng dong
2
trung binh tinh theo phuong thing dirng nr 0,69 dSn 0,75 cm/narn va 0,5198 glcm /nam, trong
vong 100 nam (nr nam 1910 dSn nam 2011). Tai

vi tri

cot khoan HP08 0 dQ sau 24 m/OmHD co

t6c dQ i1lng dong tram tich trung binh theo phuong thing dirng tir 0,82 dSn 0,97 cm/nam, kh6i
2
2
hrong tich tu/I cm la 0,8045 glcm /nam, trong vong 66 nam (bang 1, hinh 2).
KSt qua tren r~t phu hop voi d~c diem hinh thai - dQng lire va phan b6 tram tich tai
khu bo hien dai: Hai CQt khoan
m/OmHD)

HP08

(0 dQ sau 24 m/OmHD)

va HPI0

(0 dQ sau 10

thuoc phu doi song bien dang cua doi suon bo ngam va doi song pha huy [12],

[22]. Ben canh do, tai d c i nay heat dQng cua cac ySu t6 dong luc: Song, dong chay t6ng
hop (thuy trieu,
anh huang

chay ven bo, dong chay song) 6n dinh theo mua trong

cua cac ySu t6 thai tiSt b~t thuong

nam, khong chiu

(bao), va heat dQng cua cac ySu t6 dong lire

nay cang 6n dinh.khi dQ sau khu bo cang tang len. V6i d~c diSm nay, nen su phan b6, lang

310LKJIHGFEDCBA

cMt va

t u « ponmlkjihgfedcbaZYXWVUTSRQPONM
ban D ia
T a i nguyen, K h o d n g san biin


H(Ji nghi Khoa hoc Dia eMt biin toan qu6e idn thU II zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

dong tram tfch nrong d6i 6n dinh theo khong gian va thai gian. Tuy nhien, dieu quan trong
hon ca la tai vi tri cQt mftu HP8, anh huang phu sa cua h~ thong Song Hfmg d~n vung ria
ngoai cua VCSBD Ian hon.MLKJIHGFEDCBA
C ore H P 08

0
2011

2005

" " P b ( d p m /g )
m C s ( d p m /g )
ZYXWVUTSRQPONMLKJIHGFEDCBA
C ore H P 10

0.1

0.20.1
I

10

1995

15

1990

20

1985

25

1980

30

1975

35

I

~~

+

5

2000

10

1

~

+
~

++
+

0

2005

5

2000

10

1990

15

1980

20

1985

25

1970

30

1975

35

1960

40

1970

40

1955

45

1955

45

1950

50

1960

60

1945

55

1940

60

1935

65

1955

55

1950

i60
.z:,

1945

£;

1930

70

"

1925

75

0.

~65

0

1920

H in h

" 'C s ( d p m ig )

0
2011

0.05

.T 85

1910

90

dong

va tuJi tram

1

10

+'

++

++
~

+

K

~80

1,

1915

0.1

+~

r-:
~

s:
15.

~

e lf) SQU tai 2 c(Jt khoan HP08
2: Tu6i tr6m tich theo LKJIHGFEDCBA

IL 2. 2. v J kit qua tac tl9liing

2 " 'P b ( d p m /g )

0.10.01

tic h

va

HP 10

VCSBD

V~ t6c dQ I~ng dong tram tich: trong nghien CUunay, nhom tac gia moi chi xac dinh
duoc gia tri trung binh cua t6c dQ I~ng dong tram tich VCSBD. D~ co diroc k~t qua chi ti~t v~
t6c dQ lang dong tram tich theo thai gian dn k~t hop su dung voi cac phirong phap khac nhir:
Phuong phap ky thuat huynh quang tia X d~ quet cQt khoan (X-ray fluorescence -XRF core
scaning), ky thuat nhi~u xa tia X (x-ray diffaction) d~ nghien ciru khoang v~t set va thanh
phan co h9C tram tich.
K~t qua tu6i tram tich co dQ chinh xac cao, voi chi~u dai cQt khoan xfrp xi 100 em da
co th~ xac dinh duoc tu6i lap tram tich trong yang 100 nam cho cac vung cira song va cac
thuy VI,fCyen bo la kha phu hop. K~t qua nay kha tuong d6ng voi cac k~t qua nghien ciru khac
nhau cua cac tac giai tren Th~ gioi thuoc cac thuy VI,fCkhac nhau: H6 [34], vung cira song
Amazon [31].
So sanh t6c dQ I~ng dong tram tich VCSBD voi cac thuy vue khac: No cao hon h~ dfim
pha Tam Giang - cfiu Hai (0,31-0,60 cm/nam theo [2]), thfrp hon cira Ba Lat (0,70-3,00 cm/nam
theo [13], thfrp hon so v61 cac thuy VVCyen bo Malaysia (1,57-8,64 cm/nam theo [36]).
Day la k~t qua nghien CUudang tin c~y diroc ki~m soat va lira chon ngay tir ban dfiu:

Cac cQt khoan duoc II,fUchon thu theo cac doi hinh thai - dQng lire theo quan di~m dia rnao bo
bien cua cac tac gia n6i tieng tren Th~ gioi [5], [26] va cac nghien CUu co ban cua cac tac gia

Tiiu ban Dia chat va Tai nguyen, Khodng san biin

311


H6i nghi Khoa h9C Dia cMt biin toan quoc I[m tM LKJIHGFE
If

trong mroc. [12], [22). Cac mftu v~t diroc phan tich bang thi~t bi va phuong phap hi~n dai. K~t
qua diroc tinh toan theo co s6 Iy thuyet hien dai va cac phuong trinh toan da duoc ki~m
nghiem va sir dung ph6 bien tren th~ gioi (nhir da d€ c~p 6 cac muc d~t v~n d€ va phan
phirong phap nghien ciru).

KETLU~N
Phuong phap nuclit phong xa 210Pbva 137Csda duoc ap dung danh gia t6c lang dong
va tu6i tram tich tai 2 cQt khoan VCSBD. Trong vong vai chuc nam d~n 100 nam qua, t6c dQ
lang dong tr§.m tich trong vung tang d§.n ra phia bien: tir 0,69-0,75 cm/nam va khoi lirong tich
tu/I cm 21a 0,5198 g/cm 2/nam (tai cQt khoan HPIO) d~n 0,82-0,97 cm/nam va khoi luong tich
tu/l cm 2 la 0,8045 g/cm 2/nam.
T6c dQ I~ng dong tram tich VCSBD cao hon cac thuy V\ICyen tinh (h6, d§.m pha), thap
hon vung cira song chau th6 (song H6ng). K~t qua lang dong tram tich phan anh duoc kha
nang cung dp tram tich cho vung cira song hinh ph~u: Giau tr§.m tich hon mot s6 V\ICmroc W
nhien yen tlnh va ngheo tram tich hon vung cira song chau th6.

H o p tac nghien ciru giua
Lai cam an: Nghien ciru nay duoc tai tro boi Ti~u Du an 5 -ZYXWVUTSRQPONMLKJIHGFEDC
Vien Tai nguyen va Moi tnrong bien (IMER), Vi~t Nam va Phong Thi nghiem Trong di~m

Quoc gia Dia ch~t bien, Dai hoc Tongji, Thirong Hai, Trung Quoc. Nhom tac gia xin bay to
loi earn on chan thanh d~n 2 co so tren. Nhom tac gia cling bay to loi earn an chan thanh d~n
Giao sir Chen-Feng You thuoc Phong thi nghiem Dia hoa d6ng vi, Trung tam nghien ciru h~
thong dQng hrc Trai D~t, Truong Dai h9C Cheng Kung, Dai Loan va TS. Hoang Van Long,
Truong dai hoc Mo - Dia chat, Vi~t Nam da cung thao luan v€ phirong phap tinh toan tu6i
tram tich va d6ng vi phong xa.

TAl LI¥U THAM KHAo
I. Ali Arman Lubis, 2004. Constant rate of supply (CRS) model for determing the sediment
accumulation rate in the coastal area using 210Pb.Coastal Development, pp. 9-18.
2. Albertazzi., Bellucci L.G et aI, 2007. 210Pb and 137Csin sediment of Central Vietnam
coastal lagoons: Tentitive assessment of acculation rate. Marine Science and Technology
Supplement 1, pp. 73-81.
3. B.S. Shukla, 1989. An evaluation of the CIC Model of 210PbDating of Sediment. Eviron
Geol Water Sci, Vol. 14, No.1, pp 73-76 Springer-Verlag New York Inc.
4. Bergan T.D., 2002. Radioactive fallout in Norway from atmoshperic nuclear weapons
tests [J). Environment Radioactivity, 60, pp. 189-208.
5. Bird E., 2000. Coastal geomorphilogy.

An introduction John Wilet and sons. LTD

Chichester-New York, pp. 1-322.
6. Chih-An Huh et aI., 2011. Modern «100 years) sedimentation in the Taiwan Strait: Rates
and soure-to-sink pathways elucidayed from radionuclides and particle size distribution.
Continental Shelf Research, 31 (2011), pp. 47-63.
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va

Tai nguyen, Khodng san biin

H6i nghi Khoa h9C Dia chat bien toan

qu6c tdn tM 11 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

7. Crozaz,LKJIHGFEDCBA
G ., et aI., 1964. Antarctic snow chronology with ZYXWVUTSRQPONMLKJIHGFEDCBA
2 1 o Pb.
Geophysical Research,
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8. Do Minh Due et aI., 2007. Sediment distribution and transport at the nearshore zone of the
Red River delta, Northern Vietnam. Asian Earth Sciences, 29 (2007), pp. 558-565.
9. Do Minh Due et aI., 2011. An analysis of coastal erosion in the tropical rapid accretion
delta of the Red River, Vietnam. Asian Earth Sciences,

xxx

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x x x -x x x

(in press).

10. Huh, C.A et aI., 2006. Sedimentation in the Southern Okinawa Trough-rates, turbidites
and a sediment buget. Mar. GeoI., 231, pp. 129-139.
11. Huh, C.A et aI., 2009. Modern accumulation rates and a budget of sediment off the
Gaoping (Kaoping)

River,

SW Taiwan: A tital and flood dominated

depositional

environment around a submarine canyon. Mar. Syst., 76, pp. 405-416.
12. Dinh Van Huy, 1996. f)~c di~m hinh thai - dQng lire khu bo hien dai Hai Phong. Luan an
PTS Dia

Iy - Dia

chat, Truong Dai h9C Khoa h9C T\I nhien - DHQG Ha NQi, 127 trang.

13. G.D. Van Den Bergh et ai, 2007. Recent sedimentation and sediment accumulation rates
of the Ba Lat prodelta (Red River, Vietnam). Asian Earth Sciences, 29, pp. 545-557.
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15. He Q., Walling D.E., et ai, 1996. Interpeting the 137Cs profiles observed in several small
lakes and reservoirs in southern England

[1 ].

Chemical Geology, 129, pp. 115-131.

16. Jay Stratton Noller et ai, 2000. Quanternary Geochronolgy methods and Applications.
Lead-21 0 geochronology, pp. 115-120.
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[1 ].

Earth and

Planetary Letters, 11, pp. 407-414.
18. Koide M., Soutar A. et ai, 1972. Marine geochronology with 210. Earth and Planetary
Science Letters, 14, pp. 442-446.
19. Milliman, J. D et ai, 1983. World-wide delivery of river sediment to the oceans. GeoI., 91,
pp. 1-21.
20. Milliman, J. D., et ai, 1992. Geomorphic/tectonic

control of sediment discharge to the

ocean: The importance of small mountainous rivers. GeoI., 100, pp. 525-544.
21. Lu X., 2004. Application of the Weibull extrapolation to 137Cs geochronology in Tokyo
Bay and Ise Bay, Japan [1]. Environmental Radioactivity, 73, pp. 169-18.
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Luan an PTS khoa h9C Dia

Iy - Dia

be

Delta song Hong (Holocen hien dai).

chat, 170 trang. Truong Dai h9C T6ng hop Ha N9i.

23. LJ. Turner, L.D. Delorme, 1995. Assesment of

210

Pb data from Canadian lakes using the.

CIC and CRS models. Environmental Geology, 28 (2) September 1996. Springer-Verlag.
pp.78-87.
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va Tai nguyen,

Khoang sdn bien

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tdn tM 11 zyxw

H9i nghi Khoa h9C Dia chdt bidn toan quoc

24. Dang Hoai Nhon va nnk., 20 11. Lang dong tram tich tren bai trieu Bang La va NgQCHili,
Hai Phong. Khoa hQCva C6ng nghe bien, T11 (2011), Nol, tr 1-13. ISSN LKJIHGFEDCBA
1 8 S 9 -3 0 9 7 .
2S.

Oldfield, F., Appleby. P. G et ai, 1978. AlternativeZYXWVUTSRQPONMLKJIHGFEDCBA
2 1 0 Pb dating: results from the
ew
Guinea highlands and Lough Erne. Nature (London), Vo1.271, pp. 339-342.

26. O.K. Leontyev, L.G. Nikiforov, G.A. Xafijanov, 1962. Dja mao

be

bi~n. Ban dich tieng

Nga, 372 tr. Khoa Dja Iy, Truong DH Khoa hoc TI! nhien, DHQG Ha N<)i. narn 2000.
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Finnish Peatland Society, 28, pp. 19-24.
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Holmes

c ., et ai, 2000. Time-averaged

radionuclides to sediments

fluxes of lead and fallout

in Florida Bay [J]. Geophysical Research,

pp.

1 0 S (C 1 2 ),

2 8 8 0 S -2 8 8 2 1 .

29. Sorgente, D et aI., 1999. Chronology of marine sediments - Interpretation of activity-depth
profiles of

210

Pb and other radioactive tracers. Part 1. CNR-ISMAR-Bologna,

Thechnical

Report No.S4, 32 pp.
30. Strachnov, V., et ai, 1996. Report on the Intercomparison run IAEA-37S: Radionuclides in
soil. IAEAlALl07S, IAEA, Vienna, Austria.
31. Sophie Althammer et ai, 2010. The use of the 21 OPb method for preliminary evaluating
the sedimentation rate in Amazon River mouth. Annals of Warsaw University of Life
Sciecences.
32. Trftn Duc Thanh va nnk., 1993. M6i tnrong Dja ch~t ven bo Hai
IIS 0 .0 0 0 .

Phong,

Ban

dE>

ti I~

Liru tnr Vien Tai nguyen va M6i tnrong bien, Hai Phong .

•

33. Vinh V.D, et ai, 2011. The impact ofHoa Binh dam on distribution of suspended sediment
in coastal areas of red river delta. Proceeding of
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s" National

conference of Marine Science

4 6 S -4 7 4 .

34. XU Hai, AI Li, et ai, 2006. Geochrology of a surfacce core in the northern basin of Lake
of Lake Qinghai: Evidence from

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137

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Zbigniew Pruszak et ai,

200S.

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3 6 S -3 8 S .

36. Theng, L.T., Ahmad, Z., Mohamed, C.A.R., 2003. Estimation of sedimentation rate using
210

Pb and

21O

pO at the coastal water of Sabah, Malaysia. Radioanalytical

Chemistry, Vo1.2S6, pp.

314

and Nuclear

l1 S - 1 2 0 .

t u « ban Dia chat

va Tai nguyen,

Khoang

san bidn


H(Jinghi Khoa h9C £Jia chdt biin toan quoc ldn tM IIMLKJIHGFEDCBA

SUM M ARY
IN IT IA L

RESULTS

GEOCHRONOLOGY

O F STUDY

OF M ODERN

BY M ETHODS

IN S E D IM E N T A T IO N

S E D IM E N T S

RATE

IN T H E B A C H

AND

DANG

ESTUARY

O F 2 1 0 P b A N D zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
137CS R A D I O T R A C E R

I B u i V a n V u o n g , 2 L iu Z h i F e i, I T r a n D u e T h a n h , I T r a n D in h L a n , 2 C h i-A n H u b ,
2 T u o S h o u tin g , I D a n g H o a i N h o n , I N g u y e n V a n Q u a n , I N g u y e n D a c V e ,
I D in h V a n H u y , I N g u y e n D in h K h a n g

I-Institute of Marine Environment and Resources - VAST
2Tongji University, Shanghai, China
E-mail:

The Bach Dang estuary is very large (after the largest Dong Nai estuary). It is so
important in Vietnam because where has Haiphong Seaport and in the future, this area will
have also Lach Huyen deep-water port. This estuary consists of high abundant in natural
resources concerning of tidal channels and ecosystems such as mangroves and tidal flats etc.
In addition, the sediments and topography (sedimentary rates and channel siltation) in this
area have been changed strongly and directly impacts on the resource values and economic
activities, especially the seaport logistics. The related issues have attracted alot of scientists
in the fields of delta evolution, hydrodynamics, geomorphology,
This paper

presents

initial

results

of the studies for

the

sedimentary transport, etc.
sedimentation

geochronology of modern sediments in the Bach Dang estuary. Sedimentation
from 2IoPb and I37CS profiles
accumulated/area rangedfrom

has been varied from

rates

and

rate derived

0.69 to 0.97 cm.yr' and mass

0.5198 to 0.8045 (g.cmi.yr '}. The 210Pbwas used to calculate

geochronology of modern sediment cores in the Bach Dang estuary within 100 years and
137
C ZYXWVUTSRQPONMLKJIHGFEDCBA
s should be used as an independent tracer to verify the results obtained from 210
P b.

K EY W O RDS:

Tiiu ban Dia cha:

Sedimentary rate, geochronology, Bach Dang,

va LKJIHGFEDCBA
T a i nguyen, Khodng

san biin

21O Pb, I37Cs

315