158 Qua trinh hinh thanh va phat trien cac th^nh tao ran (am tieu) san ho va cac bieu hien dau khi QUA TRINH HINH THANH VA PHAT TRIEN CAC THANH TAO RAN (AM TIEU) SAN HO VA CAC BIEU HIEN DAU KHI LIEN Q[.]
158 Qua trinh hinh va phat trien cac th^nh tao ran (am tieu) san ho va cac bieu hien dau QUA TRINH H I N H T H A N H VA P H A T TRIEN C A C T H A N H T A O RAN (AM TIEU) SAN H O VA CAC BIEU HIEN D A U KHI LIEN Q U A N v O l C H U N G CAC V U N G BIEN VIET N A M Nguyen Ngge Viin Khoa hpc vd Cong nghi Viet Nam TOM TAT Cdc vung bien Viet Nam (thim liic dia vd cdc viing biin sdu, biin xa nhu Truong Sa, Hodng Sa) la nhung noi cdc thdnh tgo rgn (dm tieu) san hd (ki ed cdc rgn Kainozoi vd cdc rgn hiin dgi) phdt triin phong phu vd da dgng Cdc kit qud nghien ciru nhimg ndm gdn day cua mdt sd tdc gid [1, 6, 12, 16] cho thdy chung cd nhirng biiu hien ddu vd cdc ddu hieu cd triin vgng vi khd ndng chira hydrocarbon Do dd chung da tr& thdnh mdt cdc ddi tugng quan trgng cua dia chdt ddu & cdc vung biin nu&c ta Di gdp phdn ldm sdng td y nghia thuc te vd dge diim phdn bd cua cdc thdnh tgo dia chdt ddc biet ndi tren, bdi viit ndy di cap qud trinh hinh thdnh vd phdt triin cua chung vd gi&i thiiu mdt sd bieu hien, cdc ddu hieu lien quan v&i triin vgng ddu cua chung & mdt sd vung biin nu&c ta tren co s& cdc tdi lieu nghien cu'u ciia tdc gid vd tdng hgp cdc tdi lieu cdng bd MdDAU Ran hay am tieu la thuat ngir dugc dich tir tiing nuoc ngoai co mgt s6 nghTa khae Trong dia chat, la cac tao carbonat nguon g6c sinh vat Tuy theo phan sinh vat tao ran (am tieu) cbilm uu thi ma chiing co cac ten ggi khae nhu ran san h6 c6 duge tao tir khung xuong cua cac nhom san h6 da tuyet chiing Paleozoi nhu Tabulata, Rugosa, v.v.; ran san h6 tre dugc tao chii yeu tir khung xuong ciia nhom san h6 tia (Hexacoralla) phat triln tir Mesozoi (dae biet Kainozoi) cho tai nay; ran Hai Mien, ran tao dgng vat, ran rong tao, v.v dugc cau tao chu yeu tir khung xuong cua cac sinh vat cimg ten Cac ket qua nghien ciru cho thiy hiu hit cac ran (am tieu) cac viing biin Viet Nam noi rieng va a Bien D6ng noi chung la cac ran san h6 (am tieu san h6) tre (tir Mesozoi din hien tai) [2-4, 7, 9-11, 12, 14-18] V l ciu tao, cac ran san h6 gIm phin chinh: la khung cirng va kh6ng gian lip diy Khung eirng la la khung xuong ciia cac quan the san h6 hay san h6 ca the, kh6ng gian bi viii lip la eae khoang trong, cac khe ho, 16 rong khung xuong cirng dugc lip diy boi cae vat lieu tram tich vyn bo cac canh san h6 bj gay nat tao va cac sinh vat khae tilt bgt voi, di tich ciia cac nhom sinh vat khae Tuygn tap bao cao Hoi nghj KHCN "30 nam DSu Viet Nam: Co' hpi moi, thach thuc moi" 159 QUA TRINH HINH THANH VA PHAT TRIEN CUA CAC RAN (AM TIEU) SAN HO Dieu kien tu nhien: Yeu to quyet dinh sy hinh va phat trien ciia cac ran san ho Dieu kien can de co ran san h6 la sy co mat ciia san h6 tao ran Nhung nhu the chua dii boi vi co san h6 tao ran nhung neu kh6ng c6 cac dieu kien ty nhien thich hgp Cac dieu kien cy the la: - Do sau cot nuoc: - 50m, c6 the Ion hon (den 90m) neu cua nuoc biin cao, t6i uu la - 20m nuoc; - Nhiet moi truang nuoc: 16°C - 36°C, tii uu 25°C - 29°C - 32°C; - Ham lugng mu6i nuoc: 28%o - 40%o, tii uu 32%o - 36°/oo; - Do cua nuoc cao (hay dye thap); - Che thuy dgng lyc ciia m6i truong trung binh; - It hay kh6ng co sinh vat gay hai; - Phai CO nen day cimg de sinh vat bam vao s6ng va phat trien (cac sinh vat tao ran la cac sinh vat s6ng bam c6 dinh vao nen day cimg); v.v Qua trinh hinh cua cac ran san ho 6' cac viing bien Viet Nam a Vi mat sinh hgc Sau cac au triing san h6 tao ran tim thay noi co nen day cimg va cac dieu kien s6ng thich hgp, ehiing bam vao sinh s6ng va phat trien Khi dat toi cyc thinh, the he gia c6i chet di va khung xuong ciia chiing tao nen khung cimg eua ran Ran dugc hinh tir Theo thoi gian, cac the he san h6 phat trien ch6ng chat len lam cho ran phat trien ca ve the tich va ben vting b Vi mat dia chdt O cac viing bien Viet Nam noi rieng va Bien Dong noi chung, cac ran san h6 hinh va phat trien ciing voi qua trinh hinh va phat trien ciia Bien D6ng Qua trinh tach gian day Bien D6ng keo theo sy hinh moi truang bien nuoc bien Thai Binh Duong tran vao tir cac phia Bae, D6ng va Nam Tuy nhien, cac ket qua nghien ciru kien tao, c6 dia ly va dia chat khu vyc cho thay mac dau qua trinh tach gian day Bien Dong xay each day 32 trieu nam ve truoc Oligocen, nhung phai den dau Miocen duoi che bien ciia Bien D6ng moi thye sy 6n dinh mgt s6 noi va co dii cac dieu kien thich hgp cho san h6 tao ran phat triln de tao nen eae ran san h6 (mac dau vao Oligocen mugn ciing da eo cac tao ran san ho phat trien cae khu vyc lan can nhu Tay Bae Palawan (Philippin) ma diu vlt ciia chiing dugc bilt duoi ten he ting da v6i ran san h6 Nemo [19] Cac tao ran san h6 phat triln rong rai tir diu Miocen din Holocen cac vimg biin Hoang Sa, Truang Sa, Tu Chinh - Vung May, V.V 160 Qua trinh hinh va phat trien cac tao ran (am tieu) san ho va cac bieu hi^n dau Qua trinh phat trien ciia cac ran san ho ff cac viing bien Viet Nam Cac ket qua nghien ciiu cua cac chuyen gia san h6 [15, 19] cho thay a cac vimg bien Viet Nam co gan 70 gi6ng san h6 tao ran voi tren 300 loai Tren co so phan tich dac diem phan b l dia ting lich sir phat trien ciia san h6 tao ran a cap gi6ng co the phan biet dugc cac nhom sau: - Nhom gi6ng truoc De tam: t6n tai tir Jura - Creta cho den - Nhom gi6ng Paleogen: t6n tai tir Eocen - Oligocen cho tai - Nhom gi6ng Neogen som: ton tai tir Miocen toi - Nhom gi6ng Neogen mugn: t6n tai tir Pliocen toi - Nhom gi6ng De tii som: t6n tai tir Pleistocen - Nhom giong De tii mugn: t6n tai tir dau Holocen toi Cac nhom gi6ng noi tren phan anh tinh giai doan lich sir phat trien ciia san h6 tao ran vimg Bien D6ng noi chung Tuy nhien, ve dia tang tram tich Kainozoi a cac viing bien Viet Nam chi co mat cac tram tich co tu6i tir Eocen toi Holocen (trir khu vuc Ian can la Tay Bae Palawan thuoc Philippin co cac tao ran (am tieu) san h6 tu6i Oligocen mugn) Trong do, cac tram tich Eocen va Oligocen chu yeu la tuong lyc dia (s6ng, h6, tam giac chau) Cac tram tich tir Miocen duoi den De tii rat da dang ve ngu6n g6e va phan thach hgc, dac biet cac nhom be carbonat va tram tich - carbonat (xem chi tiet duoi) cac tao ran (am tieu) san h6 phat trien lien tuc hay gian doan nhieu noi Nhu vay, cac viing bien Viet Nam va Ian can, qua trinh phat trien cua cac ran (am tieu) san h6 chi g6m co giai doan sau (Bang 1): - Giai doan Paleogen mugn (Oligocen) - Giai doan Neogen som (Miocen) - Giai doan Neogen mugn (Pliocen) - Giai doan De tii som (Pleistocen) - Giai doan De tii mugn (Holocen) Trong do, m6i giai doan dac trung bang su xuat hien cac gi6ng, loai moi ben canh cac giing, loai da xuat hien tir truoc Nhu vay, qua trinh phat triln ciia cac ran san h6 xay theo huong da dang hoa phan sinh vat tao ran TuySn tap bao cao Hoi nghi KHCN "30 nam DSu Viet Nam: Co' hoi moi, thach thuc moi" Bang 1: Cac giai doan phat triln cua san ho tao ran va ran san ho Viet Nam va cac vung bien lan can Giai dogn De t u muon (Holocen) De tu som (Pleistocen) Neogen muon (Pliocen) Neogen (Miocen) Oligocen som Thdnh phdn gidng san hd tgo rgn - Anacropora, Pseiidosiderastrea Coeloseris, Herpolitha Halomitra Polyphyllia, Sandalohtha, Podohacea, Acrhelia, Oxypora, Mycediwn, Pectinia, Cynaria, Syiuphyllia, Meriilia, Scapophylla, Barabattoia Oulastrea, Plerogyra, Physogyra, Tulastrea; - Coscinaria; - Scolymia; - Seriatopora, Psainmocora, Pachyseris, Galaxea, Echynophyllia, Plesiastrea, Echinopora, Trachyphyllia -Acropora, Montipora, Porites, Stylocoeniella, Pocillopora, Stylophora, Mantipora, Alveopora, Favites, Caulastrea, Goniastrea, Platygyra, Euphyllia, Pavona, Leptoseris, Lithophyllon, Cyphastea, Oulophyllia, Turbinaria - Montastrea, Diploastrea, Favia, Hydnophora, Cycloseris, Goniopora, Madracis, Astreopora.Leptoria - Co.scinaria; - Scolymia; - Seriatopora, Psammocora, Pachyseris, Galaxea, Echynopliyllia, Plesiastrea, Echinopora, Trachyphyllia - Acropora, Montipora, Porites, Stylocoeniella, Pocillopora, Stylophora, Mantipora Alveopora, Favites, Caulastrea, Goniastrea, Platygyra, Euphyllia, Pavona, Leptoseris, Lithophyllon, Cyphastea, Oulophyllia, Turbinaria - Montastrea, Diploastrea, Favia, Hydnophora, Cycloseris, Goniopora, Madracis, Astreopora,Leptoria - Scolymia; - Seriatopora, Psainmocora, Pachyseris, Galaxea, Echynophyllia, Plesiastrea, Echinopora, Trachyphyllia - Acropora, Montipora, Porites, Stylocoeniella, Pocillopora, Stylophora, Mantipora, Alveopora, Favites, Caulastrea, Goniastrea, Platygyra, Euphyllia, Pavona, Leptoseris, Lithophyllon, Cyphastea, Oulophyllia, Turbinaria - Montastrea, Diploastrea, Favia, Hydnophora, Cycloseris, Goniopora, Madracis, Astreopora,Leptoria - Seriatopora, Psainmocora, Pachyseris, Galaxea, Echynophyllia, Plesiastrea, Echinopora, Trachyphyllia -Acropora, Montipora, Porites, Stylocoeniella, Pocillopora, Stylophora, Mantipora, Alveopora, Favites, Caulastrea, Goniastrea, Platygyra, Euphyllia, Pavona, Leptoseris, Lithophyllon, Cyphastea, Oulophyllia, Turbinaria - Montastrea, Diploastrea, Favia, Hydnophora, Cycloseris, Goniopora, Madracis, Astreopora,Leptoria - Acropora Montipora Porites Stylocoeniella, Pocillopora, Stylophora, Mantipora Alveopora, Favites, Caulastrea, Goniastrea Platygyra Euphyllia, - Pavona, Leptoseris, Lithophyllon, Cyphastea, Oulophyllia Turbinaria - Montastrea, Diploastrea Favia, Hydnophora, Cycloseris Goniopora, Madracis Astreopora, Leptoria Nhdm gidng Holocen Hien dai Pleistocen Hien dai Neogen muon (Pliocen Hien dai) Neogen sffm (Miocen Hien dai) Oligocen Hien dai 162 Qua trinh hinh va ph^t trien c^c tao ran (am tieu) san ho va cac bieu hien dau Mot s6 bieu hien dau cac tao ran (am tieu) san ho ff cac viing bien Viet Nam D I de hinh dung va tien theo doi viee m6 ta cac bieu hien va dau hieu lien quan den triln vgng diu cac tao ran (am tieu) san h6, chiing ta lam quen mgt each ngin ggn voi cac kieu be tram tich va dac diem phan b6 dia tang cua cac tao ran san h6 o cac vimg bien Viet Nam a Phdn loai ede bi trdm tich Kainozoi ff cdc viing biin Viet Nam theo ddc diim trdm tich Tren co so dac dilm phin trim tich phat trien chiem uu thi va dieu kien tao chung, cac bl trim tich Kainozoi a cac viing bien Viet Nam dugc chia nhom: - Nhom bl trim tich lyc nguyen: Bic be S6ng H6ng, be Cim Long va be Malay Thi Chu - Nhom bl trim tieh luc nguyen - carbonat: Nam be S6ng H6ng, be Nam C6n Son, be Phii Khanh - Nhom be carbonat: nhom be Hoang Sa, nhom be Truong Sa va Tu Chinh - Viing May Trong nhom be thii nhat, cac tram tich dugc tao chii yeu la cac tram tieh manh vyn co hat khae tir th6 toi mjn (cuoi - s6i - eat, bgt va set), phan carbonat rat hiem, chii yeu dang ximang gan ket Trong nhom be thii hai, cac tao tram tich lyc nguyen va cac tao carbonat thuang nam xen ke hay theo phan nao chiem uu the ma chiing tao nen cae mat cat dac trung khae Trong nhom be nay, cac tai lieu thyc te (thi du be Nam Con Son va phan Nam be S6ng Hong) cho thay cac tao carbonat thuong co dang la carbonat dang them va cabonat dang ran (am tieu, chu yeu la san h6) Trong cae tao thir nhat thuong CO cau tao dae xit, r6ng rat nh6, cac tao thir hai co ring Ion (10% din tren 20%) Trong nhom be thir ba, cac tram tich chii ylu la cac tao carbonat ngu6n g6c sinh vat, a cac cym be Truang Sa, Hoang Sa, Tu Chinh - Viing May - la cac tao carbonat ran san h6 b Ddc diim phdn bo dia tdng cda cdc thdnh tao ran (dm tiiu) san ho & cdc viing biin Viet Nam Nghien cim dac diem phan b6 dia tang cae tao ran (am tieu) cac bl trim tich cac viing bien Viet Nam cho thay o nhom bl carbonat chiing phan b l lien tuc hay tuong d6i lien tyc tir Miocen duoi den Holocen tren, nhom bl trim tich lyc nguyencarbonat chiing phan b6 ehii yeu Miocen duai (Nam bl S6ng H6ng) hay Miocen giira (Nam C6n Son) (Bang 2) 163 Tuygn tap bao cao Hoi nghj KHCN "30 nam D5u Viet Nam: Co' hoi moi, thach thiic moi" Bang 2: Phan bo dia tang cac tao ran (am tieu) cac be tram tich ff cac vung bien Viet Nam \ Nhdm be Dia tdng ^^ Nhdm bi trdm tich luc nguyen carbonat Nam be Sdng Hdng Nam Cdn Son Phil Khdnh Nhdm be carbonat Cum be Hodng Sa Cum be Tu Chinh Tru&ng Sa Viing Mdy Holocen + + + Pleistocen + + + Pliocen + + + ? + + + ? + + + ? + + + ? ? ? Miocen tren Miocen giua ? Miocen duoi + Oligocen + c Mot SO biiu hiin, ddu hiiu cdc thdnh tao ran (dm tiiu) liin quan din triin vgng ddu ff cdc viing biin Viet Nam Cac nghien ciiu gan day ciia mgt s6 tac gia [1, 5, 6, 12, 16] cho thay cac tao ran (am tieu) mgt s6 be tram tich cac viing bien Viet Nam la mgt cac d6i tugng quan trgng cua dia chat tim kiem tham dau Chung la nhirng tang chiia hydrocarbon ly tuong vi co r6ng cao (10%) den tren 20%), co the tich Ion, dien phan b6 rong Mgt s6 bieu hien dau da dugc ghi nhan, mgt s6 dau hieu lien quan den trien vgng dau da duoc xac dinh Cy the: - Tai them lyc dja mien Trung Viet Nam thuge phan phia Nam be S6ng H6ng, a 16 115, gieng khoan 115-IX thuge dai nang Tri T6n, cac tram tich Miocen duoi g6m cac da co phan packstone, grainstone, bindstone, cae khung xuong tao d6, san h6, triing 16 dugc c6ng ty IPL cho la dac trung cua carbonat ran san h6 thuge kieu ran chan bo Chung co dien phan b6 rong, co r6ng 10 - 24%, chira trir lugng rat Ion (khi a day co ham lugng CO2 thay d6i tir 0,2%) den 85%) Cac da carbonat am tieu day dugc coi la d6i tugng quan trgng cua tham dau [12] - Cac tao carbonat dang am tieu a cac khu vyc 04-A, Mia, 05-TL Bae, 06-LT, LD thuge pham vi b6n triing Nam C6n Son co phan la khung xuong cac quan the san h6, rong tao v6i, vo triing 16, v.v thuoc he tang Th6ng - Mang Cau (Miocen gitra) CO rong 10% - 20%) la nhiing ting chiia thuge loai tit den rit tot [1] - Bang t6 hgp cac phuong phap nghien ciiu dia chit, dia vat ly, cac phuang phap hoa ly - carota khi, nhom tac gia Nguyin Cong Khae va n.n.k (2004) da phat hien doi am tieu chira diu tai giing khoan DX viing mo DHX Khi thir via doi cho dong dau c6ng nghiep (via chi diy c6 5,2m, nhung da cho san lugng 4.200 thiing/ngay dem [6] 164 Qua trinh hinh va phat trien cac tao ran (am tieu) san ho va cac bieu hien dau - Cac ket qua nghien cim thach hgc gieng khoan PV-94-2X a khu vyc doi nang Tu Chinh (trong \ung bien Tu Chinh - Viing May) ciia Ng6 Xuan Vinh cho thay cac tao tram tich Miocen De tir co be day tren 1000m la cac tao am tieu san h6 Duoi goc danh gia trien vgng dau khi, tac gia cho rang day la nhung tang chira trung binh va t6t [16] Ngoai mgt sl bao cao luu trii ciing co nhirng th6ng tin cac mirc khae ve cac bieu hien va cac dau hieu lien quan den trien vgng dau ciia cac tao ran (am tieu) cac be tram tich Kainozoi cac viing bien Viet Nam KET LUAN Trong mgt s6 kieu be tram tich Kainozoi o cac viing bien Viet Nam (them lye dia va cac vLing bien sau, bien xa nhu Truong Sa, Hoang Sa) cac tao ran (am tieu) san h6 phat trien rong rai, kha phong phu va da dang Chiing hinh va phat trien lien quan chat che voi cac dieu kien cua m6i truong s6ng (ke ca cac dieu kien sinh hgc va phi sinh hgc), voi qua trinh hinh va phat trien ciia Bien D6ng Trong lich sir phat trien dia chat khu vyc ehiing gap tir dau Miocen som (trir khu vyc lan can nhu a Tay Bae Palawan (Philippine) gap tir Oligocen) den Holocen nhom be carbonat hay Miocen duoi va Miocen giu'a o nhom be tram tich lyc nguyen - carbonat Cac ket qua nghien ciru gan day ciia cac tac gia khae cho thay chiing co nhirng bieu hien dau quan trgng va nhtrng dau hieu lien quan den trien vgng dau Do do, cac tao ran (am tieu) noi chung cae vimg bien nuoc ta dugc coi la mgt nhtrng d6i tugng quan trgng ciia dia chat tim kiem tham dau Trong qua trinh nghien cim, xac dinh mau vat, tac gia nhan dugc sy giiip nhiet tinh ciia chuyen gia san h6 Nguyen Huy Yet (Phan vien Hai duong hgc tai Hai Phong) Tac gia xin chan cam on TAI LIEU THAM KHAO D6 Bat, Nguyen The Himg, Nguyen Quy Hiing, Ng6 Xuan Vinh, Do Viet Hilu, Nguyen Trung Hieu, Nguyen Ngoc, 2003 Trdm tich De tam vd vi tri dja ldng lien quan din bieu hien ddu them luc dia Viet Nam Tuyen tap bao cao Hgi nghi KHCN "Viin Ddu Khi; 25 ndm xdy dung vd tru&ng thdnh'\NXB Khoa hgc va Ky thuat Ha N6i5-2003,tr 381-387 Guo Li-fen, Nie Bao-fu et al., 1994 Modern coral reefs in South China Sea Oceanography of China Sea, Vol 2, p 447 - 456, Dordreeht/Boston/London He Q Zhang M., Li H., 1988 Study on coral reef stratigraphy since Miocene in China The INQUA Intern Symp on Sstratigraphy ad correlation of Quaternary deposits of the Asia and Pacific region in Nakhodka, USSR, p 83 - 85 CCOP Technical secretariat Trinh The Hieu 1991 Cdc kieu rgn san hd vimg qudn ddo Tru&ng Sa Tuyen tap bao cao Hgi nghi Khoa hgc Bien toan qu6c III, Ha Noi Tap 2, tr 224 - 229 Tuyen tap bao cao Hoi nghj KHCN "30 nam Dau Viet Nam: Co hoi moi, thach thiic moi" 165 Nguyen Quy Himg va n.n.k., 1997 Minh gidi tdi lieu dia vdt ly nhdm nghien ciru cdu true dia chdt vd ddnh gid trien vong ddu khu vuc qudn ddo Hodng Sa vd phdn mien Trung Phong Luu trtr, Vien Dau Khi, Ha Noi Nguyen Cong Khae, Nguyen Tuin Anh, Nguyen Van Huin, Nguyin Hu\- Binh Pham Dinh Hien, 2004 Nghien ciru, khdo sdt d&i dm tieu (reef) chira ddu dua tren tdi lieu dia chdt, dia vdt ly Tuyen tap bao cao Hgi nghi Khoa hgc 16, Dai hgc M6 - Dja chat, Ha Noi, 15-11 -2004, tr 4 - Nguyen Van Luong, Duong QuIc Hung, 2001 Cdu tnic dja chdt tdng ndng vimg ddo Tru&ng Sa theo tdi lieu dia chdn ndng phdn gidi cao Tap chi Khoa hgc va C6ng nghe Biin, sl 3, tr 4 - , Ha Noi Medvedev V.C, lonin A.C, Pavlidia lu A., 1985 Tiin hod cdc rgn san hd vd su hinh thdnh cdc them luc dia cd ngudn gdc rgn Trong "Dia chat va dia mao them va suon lyc dia", tr 35 - 47, Nedra, Moskva (ban tiing Nga) Nguyen Ngge, 1999 Rgn san hd vd sinh vdt tgo rgn viing qudn ddo Trudng Sa TLLT, 44tr., Ha Noi 10 Nguyen Ngge, 2000 San hd tgo rgn vd rgn san hd viing qudn ddo Truong Sa TLLT, 73tr., HaNgi 11 Nguyen Ngge, 2004 Qud trinh hinh thdnh vd phdt trien cdc rgn san hd & viing biin Tu Chinh - Tru&ng Sa vd ldn can TLLT, 44 tr Ha Noi 12 Ly Truong Phuong, 1998 Dd cabonat thim luc dia miin Trung Viet Nam Tap chi Diu khi, s6 7, tr 2-7, Ha Noi 13 Sorokin lu.I., 1990 Nghiin ciru he sinh thdi rgn san hd 503 tr., Moskva (ban tiing Nga) 14.Tran Dire Thanh, Nguyen Dinh H6ng, 1991 Cdu true vdphdn bd he thong dm tieu san hd viing qudn ddo Truong Sa Hai quan, 5(42), Hai Phong 15.Vo Sy Tuan, Nguyen Huy Yet, 1995 Coral reefs and building coals of Vietnam Collection of marine research works, T IV, p 101 - 110, Nha Trang 16.Ng6 Xuan Vinh, 2000 Dia chdt vd tiim ndng ddu khu vue d&i ndng Tu Chinh, Tdy Nam qudn ddo Truong Sa trin co so nghien eiru giing khoan PV-94-2X Tap chi Diu khi, sl 4+5, tr - , HaNgi 17.Xia K and Huang C , 1994 Geological structure and geophysical characteristics of Nansha block in South China Sea Oceanography of China Sea, Vol 2, p 373 - 384, Dordreeht/Boston/London 18 Nguyen Huy Yet, 1994 Hi sinh thdi san hd Viet Nam Chuyen khao biin Viet Nam, T IV, tr 287-342, HaNgi 19 Nguyen Huy Yet, 1997 TJidnh phdn lodi san hd cirng vd cau true rgn san hd ddo Thuyen Chai (qudn ddo Trucmg Sa) Tuyen tap cac C6ng trinh nghien cim dilu kien ty nhien va tai nguyen thien nhien viing quan dao Truong Sa, Vien Hai duong hgc Ha Noi, tr 351 -365 ... tieu) san ho va cac bieu hi^n dau Qua trinh phat trien ciia cac ran san ho ff cac viing bien Viet Nam Cac ket qua nghien ciiu cua cac chuyen gia san h6 [15, 19] cho thay a cac vimg bien Viet Nam. .. Huy Yet, 1994 Hi sinh thdi san hd Viet Nam Chuyen khao biin Viet Nam, T IV, tr 287-342, HaNgi 19 Nguyen Huy Yet, 1997 TJidnh phdn lodi san hd cirng vd cau true rgn san hd ddo Thuyen Chai (qudn... cac ran san h6 xay theo huong da dang hoa phan sinh vat tao ran TuySn tap bao cao Hoi nghi KHCN "30 nam DSu Viet Nam: Co'' hoi moi, thach thuc moi" Bang 1: Cac giai doan phat triln cua san ho