Cau true cua b ai trieu duoc xem xet dudi goc di.'>quan h~ khorig gian cua cac ldp tram tich co tu6i va ngudn goc khac nhau, be day cua chung va quan h~ cua vi tri mat ldp vdi muc IHidC
Trang 2TAl NGUYENutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
,
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MOl TRUONG BIEN
mUNG T A M KHOA HOC T l J NHIEN V A eONG NGH~ Quae GIA
~UYEN TAP CAC CONG TRINH NGHIEN Cl1U)
T~P VI
B A N B I E N T .<\P:qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
Truong ban:
rnu ky:
C ac thanli oien:
PGS, TS Nguyen Chu Hoi
TS Nguyen Huy Yet
TS Nguyen Van Tien
TS Nguyen Due Cu
TS Tran Due Th~nh
TS Luu Van Dieu
TS Nguyen Hiru Cit
TS Do Cong Thung
HA NOI - 1999
Trang 3T a i n g u ye nutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAvdM 6 i qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA truang hiln T a p VI
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Trang
l Thanh tich 40 narn heat dong khoa h9C - c6ng n ghe cua Phan vien Hai 5
d uong hoc tai Hai Phong (1959 - 1999)
N guyln C hu H B i
2 Danh gia xu the bien de)ng mot so yeu to chat luong m6i truong nuoc bien 19
yen bo mien BAc Viet N am
Liru V an D isu, N guyen C lue H B i
3 Ham luong mot so kim loai nang trong nude vjnh H~ Long (7/1998) 27
.! Hau qua m6i truong do dan h bat ca bang hoa chat doc xyanua den h~ sinh 39
thai san h6 va ngu6n lei bao ngu vung bi~n Bach Long Vy
5 Thu hep kh6ng gian vung trieu cua s6ng Bach Dang la mot trong nhimg 54
nguyen nhan quan trong gay sa bdi luong vao cang Hai Phon g
N guyln D ue C i:
6 Dia t<ing Holoxen va cau true bai trieu yen bo Hai Phong 70
T rdn D ue T lu:L nh
7 Mot so van de co ban ve dia m6i truong yen be Viet Nam 87
T rtin D ue T hanh.
8 Dac trung hinh thai - de)ng luc va dinh huong phat tri~n ben vimg vung yen 98
bo Hai Phong - H~ Long
D inh V an H uy
9 'I'ram tich hat min mau loang 16 trong cac cot mau thang dung d vinh BAc Be) 106
N guyen C hu H B i, N guyln Q uang T utin,
N guyln V ii T utin va N guyln N goc Truitng
10 Noi dung co Sd du lieu phuc vu danh gia nhanh moi truong ddi bd bien Viet 117
Nam
T rtin D inh Ltin.
11 T6ng quan tinh hinh nghien cuu tai nguyen va m6i truong dam pha 126
yen bo mien Trung Viet N am
N guyln H ilu cit
12 Dia chat moi truong trong danh gia tac dong m6i truong 143
N guyln H ia i cit
13 Su co mat phan hoa (Palynological events) trong tram tich De tam d Viet 152
Nam va y nghia dia t<ing cua chung
Ph.am Q uang T rung, D ijng V ii K hJi, D 6 vue nu«
14 Tinh hinh nghien ciru rong - co bien d Viet Nam 169
Trang 4BfA TANG HOLOXEN vA CAU TRUC BAI TRIEU
VENwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ao HAl PHONGutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA(*)hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
T ai nguyen viL M oi truong b ii'll T fJp V I qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
T rdn D ue T hanh
Dia tang Holoxen a nude ta da duoc nghien ciru a nhieu vung dong bang
them song, them bien va cac thanh tao tram tich co ngudn goc khac nhau Tuy
nhien dia tang Holoxen va cau true cac bai trieu ven bo con it duoc nghien ciru
chi tiet Hai Phoug narn a vi tri chuyen tie'p gifru ven bo dong b~c va chau th6
song Hong Day la noi co dien tich vung tr ieu rat rong tdi 24 240ha, cac bai
trieu rat di~n hinh cho khu vue co che dQ nha t trieu bien ctQldn va tieu bi~u cho
eel dai ven bo SHot hI Mong Cui de'n Nga Son Ke't qua nghien cuu dUQCtrinh
bay trong bai viet nay se la mdt dong gap cho hi~u biet ve dia tang va cau true
cua bai trieu - mot th~ dia chat hien dai quan trong a ven bo Day cling la co sa
khoa hoc thie't yeu d~ xac dinh xu the' tie'n hoa ddi ven bo Hai Phong trong
Holoxen
Bai viet nay duoc dua tren ke't qua dieu tra khao sat nhieu na m cua mdt so
ete tai, trong eta quan troug uhat In ccug trinh "Moi trucng dia chat ven bo Hai
Phong" So lieu thuc te' va mau vat phan tich duoc thu thap tu 145 10 khoan
tay, 115 phau dien dao ete'n etQsau 3m treu vung trieu va hang chuc 10 khoan
cong trinh sa u ete'n 25m Phan tich c6 sinh - dia t:ing In phuong phap nghien
cuu chu dao 140 mau c6 sinh eta duoc phan tich gom cac nhorn tao Silic do Trtin
Due Thanh va Dao Thi Mien thuc hien, Bao tit phan hoa do Dinh Van Thuan va
Nguyen Bao Khanh thuc hien, Trung 10 do Nguyen Ngoc va Nguyen Hiru G it
70
Trang 5T ai nguyen qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA vii M {)i truong bien T ap V IwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
thuc hien va Than mern do Lang Van Ken thuc hien D~ h6 tro cho viec xac
dinh tu6i trarn tich da tien hanh so sanh lien ket cac thanh tao tram tich vdi
cac ngan bi~n them bi~n va de cat bien Ngoai tham khao cac gia tri tu6i tuyet
doi dfi.cong boo can ap dung cac phucng phap phan tfch tai lieu khao c6 va lich
su Cau true cua b ai trieu duoc xem xet dudi goc di.'>quan h~ khorig gian cua cac
ldp tram tich co tu6i va ngudn goc khac nhau, be day cua chung va quan h~ cua
vi tri mat ldp vdi muc IHidC trieu hien dai (thap nhat, trung binh va caoutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAnhfft).
('j day cau true cua cac lop tao bai trieu duoc xem xet tit rmrc ngang muc trieu
thap nhat trd leu Trong vung nghieu cuu, rnuc trieu thap nhat co gia trj Om di.'>
sau (Om hai d6) muc trieu trung binh cao 1,9m va rnuc tr ieu cao nhat 4m Vi
trf cua cac ki~u mat cAt ducc d~t trong cac ddi heat di.'>ngkien tao hien dai [2]
d~ thay duoc moi quan h~ gifta cau true bai trieu voi chuyen dong kien tao hien
dai
3.1 Dia tang Holoxen vimg vcn be)
Viec phan chia dia tang Holoxen d day chu yeu dua theo cac don vi co ban la
h~ tang Hai Hung va h~ tang Thai Binh cua Hoang Ky [5,6], co tham kliad cac
•
tai lieu g:in day cua Ngo Quang Toan [11] Tuy nhien do tai lieu c6 sinh phong
phu, co phan tfch dinh lucng nen ket qua phfin chia trong nghien cuu nay chi
tiet hon va co met so khac biet ve ngudn goc tram tich Nhirng mo ta dia tang
dudi day chu yeu nit ra tit ket qua nghien diu cac cQt khoan d phia dong b£c D6
Sen noi co vung trieu rorig ldn va be day Holoxen thuoug chi 10 - 14m (hinh 1)
o phia tay nam D6 Son be day tram tich Holoxen dat den 30m va mire cIi.'>
nghien diu con han che
3.1.1 T hong lIoloxen dum - giiia, h¢ tli'n/: H di H ung (Q [v'.2hh)
Tram tich thuong co be day 1 - 11m, trung binh 9m, g6m ba phan:
• Ph:in duoi (a, l Q,y' 2hh - a). day 1,5 - 3m, khong Ii.'>tr en mat va phu true
tiep tren h~ t:ing Vinh Phuc (Q IJ,2), phan bo han che T'ram tich aluvi song g6m
cat nho xarn vang, ngheo di tich sinh vat, gQ.pduci dao Cat Hai Trjirn tich h6
dam luc dia chua g~p d Hai Phoug nhung g~p d phan giap ke thuoc huyen Yen
Hung (Quang Ninh), g6m cat bo t xarn phdt vang luc chira tao Silic luc dia
• Phan gifra (m b, m Q ,y'.2hh - b), day 0',5 - 6m, trung binh 3m, ph6 bien
rong khap va g6m hai ki~u ngucn goc 'I'ram tich d:im lay bi~n g6m set bdt, bot
Trang 6T a i n g u ye n qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAva M 6 i tru a n g b iln T a p V IwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
Ky Cot Be day
I.hieu dia tang (m) ~c diem tclm tioh v~ di tich sinh v~t
14- Tram tich song - bien (am IV) (b-c) khong phan chia, gom set bot, bot set, rnau nau, nau xarn 13- Tram tich ho - dam lay (Ib IV) tb-ci, gom set, set bot, rnau xarn den, nhao 12- Tram tich dam lay - bien (bm IV) Ib-c),
gom set bot, rnau xarn nau, lfin nhieu mun hCtu co, xac thirc vat ng~p man.
11- Tram tich bien - song (m a IV) Ib-c). gom set, bot, mau xarn nau, lfin vun vo sinh vat bien, thuoc bai trieu thap hien dai 10- Tram tich bien (m Iv 3 Ib-c), cat thach anh, cat sinh vat vo voi, cuoi voi, set bot, bot rnau xarn tro.
;1\
ql\
M L- ~ -~
9- Tram tich dam lay - bien (bm IV) (b-b), gom set, set bot deo quanh rnau xarn xanh, chua t~1OSilic luc dia uu the hen bien, qiau xac thuc vat, nqheo Trung 16 va Than memo 8- Tram tich bien (m Iv 3
Ib-b), gom cat nho rnau xarn vanq, vanq nhat, lfin nhieu vun vo sinh vat Than rnern va San ho.
7 - Tram tich bien (m IV 3) Ib-a), gom bot, cat bot, rnau xam, xarn nau, chua
vo Than rnern bien, Trunq 16, tilO Silic bien.
6- Tram tich ho - dam lay (Ib Iv'-2 hh-b). gom set b(>t, rnau xarn, xarn den, long, lfin rnun thlfc vat chira t<'10Silic bien (1<,1man) khong dang ke, chu y~u cac danq nguon gac luc dia 5- Tram tich song - bien (am IV'-2 hh-b). gom set bot, b9t, mau xarn nau, deo.
4- Tram Hch dam lay - bien (am IV'- 2 hh-a), gom set, set b(>t, rnau xaf!1' xarn xanh, xarn den, lfin nhieu tan tich thuc v~t chlla nhieu tao Silic bien
va ph'an hoa thirc v~t ng~p man ua d(> muai cao, rat hiem Trunq I?_
3- Tram tich bien (m Iv'- 2 hh-a), gom cat b(>t rnau nau xarn, thuoc bai trieu thap, cat nho, rnau xarn vanq thuoc biii cao, con gom tang, cuoi, S<3n, cat voi, vun san he, Than memo
2- Tram tich song - bien (am 111- 2 vp), gom set bot, bot, b9t cat rnau vanq loang 15, crura tao Silic nuoc nqot va phan hoa luc dia 1- Trar,n Uc~ bien (m 11I- 2 vp), gom cat, S<3n, cuoi, chua nhieu vun Than mem bien, gan ket yeu.
H tn b 1 Dia tang tong hop tram tich bai tr ieu Hili Phong
72
cat dEW1
man (T'J Trang ca
trieu Tr
tftng Hu'
hat trur
4 - 6m lq
Q 12 IV
Pha
nguon go bot long Silic chu ngheo B:l thap dfm Trftm tic
tao uen b
trong, ch
phan gil
3.1.2 Tho
• Ph
thap va
nhieu va ngheo B
Son, den
phau gif
biJn gom caa 4 - 6 cat then tich trie
• Phan g
2 - 3m, t Trang C, Thai Bir
set.deoq ngap m~
Trang 7Tai nguyen va M 6i hgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA tru o n g biln T(ip V IwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
cat deo uot rnau xa m, xarn den, xarn xanh chua nhieu di tich thuc vat ng ap
man (TVNM), phong phii tao Si.lic bi~n, Phan hoa TVNM va ngheo Trung 10
Trong cac thau kinh cat bet g~p nhieu vo Than mern bi~u trieu thap va duci
trieu 'I'ram tich phan bo rQng khap, khong lQ tren mat, phu tr en phan thffp h~
tfrng Hai Hung hoac tren h~ tang Vinh Phuc Tram tich bien g6m cat hat nho
hat trung chua vo Than mern bien, tao uen cac them bien, de cat bi~n, cao
4 - 6m lQ t.ren mat, cat phu tren da goc phong h6a hoac tram tich dfrm Ifry bi~n
QutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA12
IY
Phfrn tren (lb, am Qly'2hh - C), day 1 - 6,5m, trung binh 4m, g6m hai ki~u
ngu6n goc: trarn tfch h6 darn l§.y luc dia ven bien c6 thanh phan cat bun, bun
bet long nhao mau xarn, xarn den chua nhieu mun b5 thuc vat muc nat va tao
Silic chu yeu nguon goc luc dia, hiern g~p dang bien, khong chua T'rung 10 va
ngheo Bao ht phan Chung c6 be day 3 - 6,5m, phan bo chu yeu d cac khu trfing
thap dong b:ic D6 Son, phu true tiep tren tram tich darn l§.y bi~n phan giira
tao n en be mat d6ng bang cao 1,5 - 4m vien quanh cac d6i nui va uam sau phia
trong, chu yeu d tay b:ic D? Sen chung phu tren tram tich darn l§.y bien, bi~n
phan gifra
3 1 2 T h O llg Il oloxen tren, h ¢ tdng T h iii R illh (Q ,/lb)
Tr§.m tich c6 be day 1 - 10m, trung binh 3m, g6m ba phan:
• Phan dudi (m Qly3 tb - a), g6m hai phu ki~u nguon goc Tr am tich trieu
thap va duoi trieu g6m cat bot, bQt mau xarn, xam nau, c6 khi xarn xanh, chua
nhieu vo Than mern bien, phong phu tao Silic bi~n, kha phong phu 'I'rung 10va
ngheo Bao tit phan Chung c6 be day 0.5 - 1,5m trung binh 1,2m d dong bic D6
Son, den 4 - 5m d tay uam D6 Son, khong lQ tren be mat, phu tren tram tich
phan gifra va phan tren h~ t§.ng Hai Hung Tram tich tudng bai bi~n, de cat
bi~n gorn cat nho mau xarn, xarn vang tao uen cac them cat bi~n, de cat bi~n
cao 4 - 6m d Nui Deo, Kien An, D6 Son va Cat Ba Chung day 1 - 3m, phu tren
cat them bien, de cat bien thucc he t§.ng Hili Hung, hoac phu chorn tren tram
tich trieu thap, dudi trieu cua h~ tfrng Thai Binh
• Phfrn gifra (m , brn, am Q ly3 t b - b), g6m ba ki~u ngucn goc T'ram tfch bi~n day
2 - 3m, thuoc he de cat bi~n tre hon, phan bo d Phu Long, Cat Hai, Dinh Vl1
Trang Cat, phu tren tram tich trieu thap, dudi trieu thuoc phan thap h~ tang
Thai Binh T'rarn tich dfrl1l lay - bi~n phan bo rQng khap Do Son, g6m bQt, bQt
set deo quanh chua nhieu di tich TVNM muc nat, phong phu Phan hoa thuc vat
ngap man (TVNM), ngheo T'rung 10 va Than mern tao Silic luc dia uu the hen
Trang 8T e l; nguyen ve l M 6 i tru o n g h iin T a p VIwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
bi~n Tr~m tich day 0,3 - Lm, trung binh 0.7m, phu tren cac tram tfch dflm Ifly
- bi~n cua h~ tflng Hai Hung, hoac tren tram tich trieu thap, duoi trieu cua he
t5.ng Thai Binh va co noi chung lQ tren mat Tram tich song - bi~n ph an bo
chu yeu d tay nam Do Son, tao n en lop be mat cua chau th6 hien dai cao
0.5-Lm, tram tfch gom bot, bot set nau, xam nau, ngheo di tich sinh vat, day 1
-2m Chung phu tren tram tich trieu thap duoi trieu cua h~ tang Thai Binh
hoac tren trarn tich song - bi~n cua h~ tflng Hai Hung
• Phan trenqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (m , m a, am , bm lb Q lv:)tb - c). gom tram tich nhieu nguon goc khac nhau: bien, bi~n song song bi~n, dam 15.y bien, ho da m, clay 0.1
-0,6m tha m chi 3 - 4m d cac bfii cat, de cat bien Trtim tich ph6 bien la cac loai
hat min nhu bun bot, set bot, mau uau xa m, xam den, xarn, uau tuy theo loai
ngucn goc Cac loai tra m tich ph6 bien la: tram tich song - bi~n gom bot, bet set
mau xa m nfiu day 1 - 2m tao nen ph an tre nhat cua ctong bang chau th6 phu
tren' tdm tich bi~n cua phan thap he tarig
Trtirn tich h6n hQP song - bi~n dam Ifly - bien tao thanh lop day 0,1 - 0.9m uam true tiep tren tram tich darn lay - bi~n xa m xanh thuoc phan giita h~ tang
Chung co thanh phan set set bot, co xu the min clan len tren Phan duoi la
tram tich song - bien, chuyen clan len tren In dam lay - bien, su chuyen tiep
kho phan biet bang mau s~c, di? hat, nhung phfin biet ro theo quan xac tao
Silic[9]
3.2.DCBA T u o i cac t r a m tich Holoxcn
Thang tu6i tuong doi cua cac tram tich Holoxen ven bo Hai Phong duoc xac lap tr en cd sd phan chi a va lien h~ cac tucng tram tich ma nguon goc cua chung
duoc xac dinh t6ng hop theo cac tai lieu c6 sinh - dia mao, thanh ph an vat chat
tram tich va cii qui luat phan bo cua chung tren cac ddi kien true co dau hieu
chuyen di?ng kien tao khac nhau Viec xac diuh thang tu6i tuong doi cua tram
tich Holoxen ven bo Hai Phong trudc het dua van nhirng ket qua phan tich chi
tiet cac nhorn tao Silic, Than memo Trung 16, Bao tit phan hoa TVNM, cac di
tich San ho va than re TVNM Nhung ket qua phan tich va nghien cuu chi tiet
tao Silic eta duoc trinh bay trong cong bo gan day [9] Tao Silic trong tram tich
Holoxen duoc ph an chi a thanh bon phuc he sinh thai Phuc he ho dam luc dia
g:,?-ptrong phan thap he tang Hai Hung, phuc h~,A5.m lay bi~n7- bi~n g:,?-ptrong
phan gifra h~ tang Hai Hung Phuc he ho dam ven bien g:,?-pdutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAtren h~ tang Hai Hung va phuc h~ cua song ven bo g:,?-ptrong' h~ t5.ng Thai Binh Phuc h~ thu hi
duoc phan chi a bon quan xac theo th u W tre dan (bang 1)
74
Trang 9T a i n g u ye n qponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAva M 6 i tru a n g b ie n T d p V I
B ang J.wvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBACac quan xac tao Silic 0 10 khoan B I (bai triclI Cat Hili)
ban Trung Long Ngu6n gee sinh thai each song
tfun chim
bi61l 1<;1 nuoc nhat troi n6i bam d.iy
G h! cltti: - Quan xac IV nguon g6c bien, ph6 bien a phtin thflp he t:lng Thai mnh.
- Qurin X3C III d:lm l:ly bien, a ph fin g iira h~ tfing Thai lflnh.
- Qujin xac II nguon g6c bai b6i chau th6 Ilgflp tri~u cao, gap a phjin tren h~ Ifing Thai
Blnh.
- Quan xac I nguon goc dam Ifiy bien hien nay.
Ket qua phan tich Bao tit phan TVNM, Trung 16, Than mern va S\1phan bo
cua chuug trong cac muc dia ting trim tich Holoxen duoc trtnh bay tr eu cac
bang 2, 3 va 4 eta gop phan xac dinh nguon goc thanh tuo va thang tu6i tuoug
etoi cua trarn tich it co trarn tich Holoxen ven bo phia b5c Viet Nam Chung coy
nghia tao thanh cac ldp danh dau va chi thi dieu kien sinh thai rat tot
Dang chu y d ria dong nam dao Cat Ba co cac ran san ho chet, hien nay lll?t
ran cao 0,5 - 1m/ OmHD Tfch tu san ho nay duoc xep VaG ph a n giira he tang
Hai Hung vdi cac dang ph6 bien P orites sp SPI.' G oreastrca sp A cropora sp
xac cua chung cling g?P trong trarn tich bai bi~n c6 chua cac di vat van hoa
Tien H~ Long d Cai Beo co tu6i CI4 la 5645± 60 nam [7]
Trang 10BdngwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA2 Phan b6 cac dang Bao tir phan TVNM trong tram tich lIoloxen ven bo Hai PhunghgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 1'0.; nguyen va M 6i tru o n g biin T ap V I
Cac di~ngutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAI 2 3 4 5 D(i cao phan b6 D(\ rnun
G hi clu«: 1- Phan gifra h~ t{lng I({li l hrng (11I11 Q,v'· 2b).
2- Phan tren h~ tfing lIili Hung (lb QI\,1.2C).
3- Phan thap b¢ tang Thai IJinh (III QI/a).
4- Phan gifra he t[lng Thai Hinh (If/ Q,/b).
5- Phan cao he tfing Thai lfinh (rn QI/C)'
x hay gap; + It Mp; - hicm gi).p; a khong gap.
TIll - trieu trung binh, T(, - trieu cao, M - man, L - 19', N - nhat.
Trong bai viet nay, thoi gian Holoxen sdrn duoc dg nghi 11 000 - 7 000 na111
trudc, Holoxen gifra 7 000 - 3 000 na m truce va Holoxen muon 3 000 narn qua
Muc tu6i tuyet doi cua cac thanh tao tram tich Holoxen ven bo Hai Phong duoc
dua vao cac co s6 sau:
van hoa Hoa Binh [7] 'I'ren dao Cat Ba co mat di tich van hoa Hoa Binh Cac di
chi van hoa Hoa Binh bi chim duoi bi~n d Cua L\lC, do bi~n tien trim vao Vao
5600 narn trudc, ling vdi nien dai Tign H~ Long d Cai Beo la thoi gian bi~n md
rQng nhat, dfly lui cu dan cua nen van hoa nay khoi dao Lop van hoa Trang
Kenh, ling vdi phan tren h~ tang' Hai Hung va narn true tiep tren tram tich
darn lily bi~n thuoc phan giua h~ tilng Hai Hung, co nien dai 3405 ± 100 narn
de'n 3005 ± 90 narn [3] Van hoa H~ Long ngoai cac dao yen bo dong b5c ling vdi
phan tren cua h~ tilng Hai Hung, tuy chua co gia tri C14
nao nhung duoc coi la khoang 4 000 - 3 000 narn truoc [8] Di chi mf thuyen Vi~t Khe (T'huy Nguyen)
thuoc van hoa Dong Son co tu6i 2000 - 2300 uam ling voi thoi gian muon nh5t
cua phan thap h~ d.ng Thai Binh Cac tu lieu vg nfi tudng Le Chan, tudng Dao
Quang I~~m tr en h~ c6n cat c6 tlnr hai co tu6i khoang 2000 na m 'I'ran Bach
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