OLIGOCEN MUON TREN MO Sir TLr DEN, L

(1)

Tuygn tap bao c^o Hgi nghj KHCN "30 nSm Dau khi Viet Nam: Co' hdi mdi, thach thiic mdi' 469

M O I TRironVG L A N G D O N G , TlTOOVG T R A M T I C H V A TtT^NG H t r u C O T R O N G THCJI KY M I O C E N SCM - O L I G O C E N M U O N

T R E N M O S i r TLr D E N , L O 15.1, B E CUtJ L O N G

Chu Dire Quang Viin Ddu Khi

TOM TAT

Phdn tieh bdo tu phdn vd tu&ng hiru eo la cdng cu m&i nhdm xdc dinh chinh xdc hi thdng ldng dong trdm tich trin co s& su dung thdnh phdn vgt chdt hiru co chua trong da trdm tich. Phuong phdp ndy Id td hgp cdc phucmg phdp phdn tich trdm tich, bdo tuphdn vd thdnh phdn mdnh vgt chdt hiru eo. Bdi bdo trinh bdy thdnh phdn mdnh vdt chdt hiru co ciia trdm tich

dugc thdnh tgo trong mdi truong luc dia vd viing chuyin tiip, vd phdn logi chiing cung nhu gid tri % thdnh phdn tir phdn tich mdu trdm tich trong mat cdt giing khoan. Viec dp dung phdn tich tu&ng bdo tuphdn bao gdm gidi thich hda thgch bdo tu phdn vd thdnh phdn mdnh

vdt chdt hiru co cho cdc trdm tich thudc hi tdng Bgch Hd (Miocen s&m), Trd Tdn (Oligocen mudn) vd Trd Cu (Oligocen s&m) thudc bi trdm tich Cu-u Ldng, thim luc dia Viet Nam.

Gidi THIEU

Nghien ciiu thanh phan vat chat hiiu CO trong da tram tich duge thuc hien bang phan tich tuong hiru co (palynofacies) tren CO so phan loai thanh phan manh palynomaceral. Phan loai thanh phAn palynomaceral dua tren eo sor dac tnmg vat ly ve cau tnic, hinh dang, kich thuoc (lan khoang 200am, trung binh khoang

100am va nho khoang 50am), do n6i, do cau (tot, trung binh va xau) va do chgn lge (tot, trung binh va xau) ma chiing ta quan sat chiing bang kinh hien vi sinh vat bang anh sang thau quang. Phan tich tuong htru CO (thanh phan, binh thiic, v.v.) co thi tim hieu dugc moi lien quan vol moi truong lang dgng tram tich.

Cac kilu tuong hihi co (Palynofacies types) dac trung cho moi truong luc dja - vting chuyin tilp ra din biin khoi dugc phan chia lam 15 kilu tuong (Hinh 2). Trong mat cAt trAm tich Miocen som - Oligocen 16 15.1, be Cim Long chimg lien quan din cac moi truang trAm tich sau:

- M6i truong biin ven bo day yen tinh (kilu I va II) - Moi truong vung vjnh kin (kilu XIII)

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Hinh 1: Vi tri dia ly mo Su" Tu Den, 16 15.1

(2)

470 Moi tru-ong ling dong, tudng tram tich va tudng hiJu co trong thoi ky Miocen sdm - Oligocen

- M6i truong dam ho (kieu XII)

- M6i truang dAm lAy ven s6ng bien (kieu XV) . Moi truang s6ng (kilu XI, XV, VII. VIII)

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Hinh 2: Phan loai tirong hfru co" theo moi trirffng lAng dong tram tich

(3)

Tuygn tap b^o c^o HQi nghj KHCN "30 nam Phu khi Viet Nam: Co" hoi moi, thach thuc moi 471

KET QUA VA TONG HOfP

Tong hgp m6i truong va tuong hiiu co theo cac tap tram tich dugc phan dinh co dac diem c6 sinh dia ting khae nhau theo trinh tu tii tren xu6ng duai cua mat c4t trim tich Miocen sam - Oligocen muon thuoc m6 Su Tu Den.

1. Tram tfeh Miocen diroi - He tSng Bach Ho - Tap dia chin B,

Dac trung c6 sinh va tuang huu co trong mat cat tram tich tren mo Su Tu Den thuoc he tang Bach Ho, dugc phan chia thanh 2 tap tram tich khae biet.

a. Phu hi tdng Bach Hd trin - Tap dia chdn B],2

Tap tram tich nay trong cac gieng khoan chu ylu la thanh phan set mau xam xanh chiem uu the trong mat cat va chua phuc he bao tu ph^n hoa rit phong phii vl s l lugng va da dang ve giong loai, bao g6m hoa thach thuoc cac nhom sinh thai nhu sau:

Hinh 3: Moi trircmg tram tich va tu-otig hiru co- trong phu he tang Bach H I tren (tap dia chdn B 1.2)

- Tao troi n6i nuac Ig/bien bao g6m Cribroperidinium spp., Leiosphaeridia spp., Tuberculonidium vancampoe, Botryocoecus spp., Botryoeoccus braunii, va foraminifera test lining.

- Tao tr6i n6i nuac nggt gom co Pediastrum spp., Pediastrum kajaites.

- Cac hoa thach co ngu6n g6c sinh thai rung sac - can rung sac gIm Acrostichum aureum, Brownlowia spp., Nypa spp., Florschuetzia trilobata, Florsehuetzia semilobata, Florschuetzia levipoli, Echiperiporites estelae, Florschuetzia ovalis, Zonocostites ramonae.

. Cac hoa thach co nguIn glc sinh thai rung dim liy ven s6ng - dim liy than bun nhu Alanglopollis spp., Arenga spp.. Calamus spp., Calophyllum spp., Campnospermaspp., Crassoretitriletes nanhaiensis, Durio spp., Eugeissona minor.

(4)

472 Moi tru-Q-ng Igng dong, tu-ong tram tich va tu-ong hu-u CQ- trong thoi ky Miocen som - Oligocen^^^

Graminae undiff, Ilexpollenites spp., MagnasTriasites howardi, Polypodiisporites perverrucatus, Merremia spp., Oncosperma spp., Stenochlaena palustris,

Pterospermum spp., STriasricolpites catatumbus, Sapotaceoipollendes spp., Lagerstroemia spp.

- Cac hoa thach co nguIn glc sinh thai khi hau 6n dai nui cao nhu Alnipollenites verus, Cedripites spp., Cycas spp., Engelhard spp., Pinuspollenites spp., Piceapollenites spp., Tsugapollenites spp., Caryapollenites spp..

- Cac bao tu phin hoa khae c6 ngu6n g6c luc dia nhu Aneimla spp., Polypodiaceaesporites undiff., Cydophorusisporites spp., Osmundacidites spp., Riccia spp., Selaginella spp., Pterisisporites spp., Lycopodium cernuum, Gleicheniacidites spp., Gemmamonoletes spp., FoveotrUetes spp., Triletes spp., Anaeardiaceae undiff, Cupuliferoipollenites spp., Dipterocarpidites spp.,

Epilobium spp., Margocolporites vanwijihel, Magnoliapollis spp., Polycolporopollenltes spp., Verrutricolporites pachydermus, Verrutricolporites spp., Randiapollls spp., Trieolporopollenites spp., Trieolpollenites spp., Retitriporites spp., Retitricolporites spp., Rutaceoipollenites spp., Shorea spp.

Tuli Miocen sam cua mat cat dugc xac dinh tren ca sa sir co mat d6ng thai cua cac hoa thach danh dau dia tang nhu Cribroperidinium spp., Apteodinium spp. (kh6ng tre han tu6i Miocen som a bien Nam Trung Hoa), Echiperiporites estelae, Florschuetzia levipoli, Florschuetzia semilobata, Eugeissona minor va Arenga spp.

Mat cat tram tich phu he tang Bach Ho tren c6 the phan chia thanh cac tap theo trinh tu tu tren xu6ng duoi vai cac dac trung ve bao tu phan va hiiu ca nhu sau:

- Tap tram tich "amorphous" tuong duong vai tang "set Rotalia": chua chu yeu la tao vong bien nhu Cribroperidinium spp., Apteodinium spp., Spiniferites spp. va thanh phan vat chat hiJu ca chu yeu la sapropel (60 - 100%) dugc thanh tao trong m6i truong bien, bien ven ba co dieu kien day yen tinh. Tinh bien tang dan theo huong Tay Nam - D6ng Bae. Tuang hiJu ca kieu IIA, loai kerogen dugc xac djnh chu yeu la I - II (sapropel - h6n hgp).

- Tap "set Bach H6" chua phuc he bao tir phan rat phong phu phan anh qua trinh bien tien dan tir m6i truang dam ho nuac nggt sang viing vinh nuac Ig, thanh phan vat chat hiru co chu yeu la palynomaceral loai 1 - 2, va chua rat it sapropel.

Tuang huu ca kieu chu yeu XII a phan duai, XIII a phin tren va loai kerogen dugc xac dinh chu yeu la loai III va II (humic va h i n hgp). Trong tap tram tich nay phan dinh dugc hai phu dai cue thjnh MagnasTriasites howardi chu yeu lang dong trong m6i truong vung vjnh nuac Ig. Phu dgi cue thjnh duai: dugc xac dinh bang sir cue thjnh cua hoa thach bao tu MagnasTriasites howardi, Merremia spp. va Acrostichum aureum. Phu dai cue thjnh tren: dugc xac djnh bSng su cue thinh ciia hoa thach bao tu MagnasTriasites howardi, Potamogeton spp. va giam di dang ke cua Acrostichum aureum va Merremia spp.. Cac phu dai nay co y nghia lan trong lien ket mat cat cac gilng khoan tren toan mo Su Tu Den.

(5)

Tuyin tap b^o c^o HQi nghj KHCN "30 n^m Plu khi Vift Nam: Co' hoi moi, th^ch thiic moi" 473

a. Phu hi tdng Bach Hd du&i

Dac tnmg cua mat cat nay chua phuc he bao tu phan hoa ngheo nan ke ca vat chat hiju CO chung to dugc 15ng dgng trong dieu kien m6i truofng dong bang s6ng co nang lugng m6i truofng cao vai thanh phan thach hgc co ty s6 cat ket/set ket tuong doi can bang. Cat ket, bgt kit, set kit co mau sac so, nau d6. Tuy nhien, co tim thiy phuc he bao tu phan hoa ngheo c6 nguon g6c daam lay than/dam lay ven s6ng la nhiing dau hieu lien quan den cac the dja chat thanh tao trong m6i truofng dieu kien nuoc tu ven s6ng CO. Ket qua phan tich tuang huu co cho toan bg mat cat la rit ngheo. M6i truang lang dgng dam lay ven s6ng/dam lay than bun diln ra trong thai gian ngin, co chua it hiru ca nhung thanh phan sapropel tuong doi cao. Mat ch. trim tich trong thofi ky nay chu yeu chua tuang hiru co loai VIII va kilu kerogen loai III. Mat cSt trim tich phu he tang Bach H6 duai chu ylu dong vai tro ting chua phan b l dge theo cac long s6ng co vai quy mo khong lan, nhung kho co dugc ting chin hieu qua trong m6i truang nay.

2. Tram tich Oligocen tren - He Tang Tra Tan - Tap dia chan C-D

Tu6i Oligocen cua mat cat dugc xac djnh tren ca sof sir co mat ding thai cua cac hoa thach danh dau dja tang nhu Cicatricosisporites dorogensis, Lycopodiumsporites neogenicus, Jussiena spp., MagnasTriasites howardi, Crassoretitriletes nanhaiensis va

Verrutricolporites pachydermus. Dac biet la trong mat cSt trim tich luon tim thiy hoa thach Verrutricolporites pachydermus (chi trong Oligocen mugn) vai tin suit cao la bing chung xac djnh tuoi Oligocen mugn.

Hinh 4: Moi trucmg tram tich va tuong hiru co- trong phu he tang Tra Tan tren ff GK SD-4X, 16 15.1 (tap dia chan C)

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474 Moi tru-6-ng ISng dong, tu-ong tram tich va tu-ong huu co- trong thoi ky Miocen som - Oligocen ....

Mat cat tram tich thanh tao trong thai ki Oligocen muon dugc phan chia chi tiet ve phirc he bao tir phan hoa va tuong hiJu co ciing nhu kieu kerogen.

a. Phil hi tdng Trd Tdn trin - Tap dia chdn C

Tap tram tich nay bao g6m cat ket, set ket va bgt ket mau sam sam co ty le tuong dii can bang va chua phuc he bao tir phan hoa kh6ng phong phii bang phu he tang Tra Tan duoi. Dac biet la hoa thach tao luc nuac nggt nhu Bosedinia spp., Pediastrum spp., Pediastrum kajaites va Botryocoecus spp., Botryoeoccus braunii.

Thanh phan tao Botryoeoccus spp. va Botryoeoccus brauni co xu huong giam dang ke theo huong tir duoi len tren mat cat. M6i truofng tram tich cua phu he tang Tra Tan tren chii yeu la viing vjnh nuac Ig chuyen dan len dieu kien dam h6 nuac ngot a phan tren cua mat cat. Thanh phan vat chat hiiu co chii yeu la sapropel mau vang den nau nhat kich thuac lan vai ham lugng 50 - 80% phan anh dieu kien m6i truang lang dong tuong d6i yen tinh, thuan lgi cho bao t6n vat chat hilu ca (m6i truang khir). Tuang htru co kieu XII 6f phan tren, XIII 6f phan duai va loai kerogen chu ylu loai I - II.

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b. Phu hi tdng Trd Tdn dw&i - Tap dia chdn D

Thanh phan thach hgc cua phu he tang Tra Tan duai 6f cac gilng khoan tren mo Su Tir Den chu yeu la set den va it cat ket chira phuc he bao tir phan rit phong phu ve so lugng va da dang ve gi6ng loai, g6m hoa thach thuge cac nhom co nguIn goc sinh thai khae nhau nhu sau: Aneimia spp., Cicatricosisporites dorogensis, Polypodiaceaesporites undiff, Riccia spp., Cydophorusisporites spp., Osmundacidites spp., Selaginella spp., Pterisisporites spp., Gleicheniacidites spp., Gemmamonoletes spp., FoveotrUetes spp., Triletes spp., Acrostichum aureum,

Crassoretitriletes nanhaiensis, Crassoretitriletes vanraadshooveni, MagnasTriasites howardi, Polypodiisporites perverrucatus, Stenochlaena palustris, Brownlowia spp., Nypa spp., Florschuetzia trilobata, Alangiumpollis

spp., Barringtonia spp.. Calamus spp., Durio spp., Gonystylus spp., Graminae undiff, Merremia spp., Pterospermum spp., STriasricolpites catatumbus, Sapotaceoipollenltes spp., Potamogeton spp., Alnipollenites verus, Cedripites spp., Pinuspollenites spp., Cycas spp.. Iris spp., Jarandersonia spp. Cac bao tir phin hoa khae c6 ngu6n g6c luc dja nhu Anaeardiaceae undiff, Cupuliferoipollenites spp., Dipterocarpidites spp., Epilobium spp., Margocolporites vanwijihel, Magnoliapollis spp., Polycolporopollenltes spp., Verrutricolporites pachydermus,

Verrutricolporites spp., Randiapollls spp., Trieolporopollenites spp., Trieolpollenites spp., Retitriporites pp., Retitricolporites spp., Rutaceoipollenites spp., Botryoeoccus spp., Botryocoecus braunii, Tasmanites spp., Bosedinia spp., Concentrycystes spp., Pediastrum spp., Pediastrum kajaites.

(7)

Tuygn tap bao cao Hoi nghj KHCN "30jTani^jiJdii_Viet Nam: Co- hoi moi, thach thiic moi" 475

Hinh 5: Moi trucmg tram tich va tuong hiru co" trong phan tren - phu he tang Tra Tan tren 6- GK SD - 2XST, 16 15.1 (tap dia chan D - phan tren)

Tren ca sof phuc he bao tir phan hoa co the chia he tang Tra Tan duoi thanh ba phan CO dac trung ve hoa thach rieng biet nhu sau:

• Phdn trin - phii hi tdng Trd Tdn du&i

Tat ca gieng khoan co phirc he bao tir phan hoa rat phong phu vai hoa thach tao luc nuac Ig Botryocoecus spp., Botryoeoccus braunii chiem uu the va giau hoa thach nhom sinh thai rimg sac, it tao vong nuac nggt Bosedinia spp. kha phong phu bao tir MagnasTriasites howardi. Day la nhting bang chung xac djnh m6i truong lang dong trong dieu kien trung tam viang vjnh nuac Ig. Thanh phan vat chat htm co chii yeu la sapropel (70 - 100%) CO mau nau, nau sam va kich thuac nho chiem tuyet d6i eo dieu kien day yen tTnh, nang lugng thap va khir. Day la m6i truong rat thuan lgi cho bao t6n vat chat htru ca tot. Tuong htru ca kieu XIII va chii yeu kerogen loai sapropel/h6n hgp (kerogen loai I/II).

Tap tram tich co dien phan b6 rong, co chieu day va m6i truang lang dgng viing vinh nuoc Ig tuong d6i 6n djnh trong loan 16 15.1.

• Phdn giira - phu hi tdng Trd Tdn du&i

Mat cat tram tich 6f 4 gieng khoan, dac trung bai phirc he bao tir phan hoa kha pho bien vai hoa thach tao vong nuoc nggt Bosedinia spp. va thanh phan co m6i truong sinh thai trong dieu kien dam lay ven song/dam lay than biin da xac nhan m6i truong lang dgng trong dilu kien dam h6 nuac nggt. Tuy nhien, trong phirc he hoa thach co chira thanh phin nuac Ig nhu Brownlowia spp., Nypa spp., Zonocostites ramonae la bing chimg xac djnh dilu kien anh huong ciia m6i truong nuac Ig bai pha biin xam nhap nhe vao khu vuc mo Su Tir Den.

(8)

476 Moi tru-6-ng ling dong, tu-ong tram tich v^ tu-p-ng hiru co- trong thoi ky Miocen sdm - Oligocen

Kit qua phan tich tuang htru ca cho thay ham lugng vat chit hiiu co rat cao vai thanh phin vat chat htru co kh6ng cau true sapropel (40 - 70%, tham chi 95 -

100%) mau nau, nau sam va kich thuac nho la chii yeu va it cac palynomaceral loai 1 va 2 CO kich thuac nh6, do mai tron xau, chgn Igc trung binh la bing chirng cho dilu kien ling dgng a gin trung tam den trung tam be co dieu kien day yen tmh va m6i truang khir kha t6t. Day la m6i truang rat thuan lgi kha tot cho bao t6n va chuyen hoa vat chat hOu ca thanh hydrocarbon theo chieu huang tao dau la chinh.

Tuang huu ca kieu XII va kerogen loai h6n hgp vai it humic xen kep (kerogen loai II).

Hinh 6: M6i trucmg ISng dong tram tich va uong hiru co- trong phan giira-phu he tang Tra Tan tren 6- GK SD-3X, 16 15.1 (tap dia chan D- phan giira

• Phdn du&i -phu hi tdng Trd Tdn duoi

Mat cat trim tich chira phirc he bao tir phin hoa kha phong phu, nhung co sir khae biet va phan thanh hai khu vuc. Phin Dong BIC cua mo chira phirc he bao tir phin hoa phan anh dieu kien lang dgng trim tich vung vjnh nuac Ig dugc chimg minh bang sir kien phong phii cua tao Botryoeoccus braunii va Botryocoecus spp. cQng nhu nhom hoa thach rimg ngap man - can rimg ngap man va thanh phin tao nuac nggt giam dang kl. Thanh phan sapropel co mau nau, nau slm va kich thuac nho chiem uu thi trong thanh phin vat chat hiJu ca la bang chimg cho dilu kien ling dgng a gin trung tam bl co dilu kien day kha yen tinh, nang lugng thap va khir kha tit. Day la moi truang rit thuan lgi cho bao tin va chuyen hoa vat chit hun ca thanh hydrocarbon theo huang tao diu la chu yeu. Tuang hthi ca kieu XIII (gin trung tam ling dgng) va kerogen loai hon hgp vai it sapropel (kerogen loai II).

(9)

Tuygn jgp^b^o cio Hpi nghj KHCN "30 nam Dau khi Vi$t Nam: Co" hoi m61, th^ch thirc moi" 477

Hinh 7: Moi truong tram tich va tuong htru cff trong phan du6i-phu he tang Tr^ Tan duoi 6- GK SD-3X, 16 15.1 (tap dia chan D- phan duoi)

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Hinh 8.:M6i truong 15ng dong tram tich va tuong hiru cff trong phan du6i-phu he tang Tra Tan duoi & GK SD-IX, 16 15.1 (tap dia chSn D-phln du6i).

Trong khi do, khu vuc Tay Nam ciia mo Su Tir Den phirc he hoa thach co ngu6n g6c sinh thai ngi luc, giau cac hoa thach ngu6n goc dam h6 than bim/ven song va vang mat cac hoa thach sinh thai nguon g6c nuac Ig/bien. Nhting bang chimg nay xac nhan m6i truong lang dgng trong dieu kien dam ho nuac nggt. Ket qua phan tich tuong hiiru ca thi thanh phan sapropel co mau nau, nau sam va kich thuac nho chiem uu the trong thanh phan vat chat hun ca la bang chimg cho dieu kien lang dgng a gan trung tam be eo dieu kien day kha yen tinh, nang lugng thap va khir kha tot. Day la moi truong rat thuan lgi cho bao t6n va chuyen hoa vat chat huu ca thanh hydrocarbon theo huong tao dau la chu yeu. Tuong hiin CO kieu XII (gan trung tam lang dong) va kerogen loai h6n hgp vai it sapropel (kerogen loai II).

Birc tranh loan canh m6i truong ling dgng trim tich o mo Su Tir Den trong suit thai ky dja chat Miocen som - Oligocen muon tuong dii In djnh. Day chinh la dilu kien thuan lgi cho cong tac lien ket dja ting cac via diu ciing nhu cac ting chin tren pham vi toan mo Su Tir Den.

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478 Moi tru-ong ldng dong, tuong tram tich va tuong huu CQ- trong thoi k\ Miocen som - Oligocen ....

KET LUAN

Trong c6ng tac tim kiem tham do cac tich tu dau khi trong be tram tich thi nghien cuu va xac dinh m6i truong thanh tao cac tap tram tich ciing nhu kieu tuong hUu ca la mgt phuang phap kh6ng thi thilu va tach rai t6 hgp nghien cuu dia chat - dja vat ly trong viec nghien cim he thong diu khi ciia bl. M6i truong lang dgng tram tich co y nghia quan trong dii vai thanh phin vat chit hiin co chira trong da tram tich. No chi ra dieu kien bao t6n va xu huang chuyin dich kerogen thanh diu khi, la dilu kien quan trgng trong danh gia tiem nang diu khi ciia mgt be tram tich.

Trong mat cit tram tich thuoc phu he tang Bach H6 tren, ket qua phan djnh dugc mot each khoa hoc cac tap trim tich trong viec lien kit cac tang chira va ting chan dja phuang trong pham vi 16 15.1. Chiing chii ylu dugc ling dong trong dieu kien dim h i nuoc nggt - viing vjnh nuoc Ig va kit thuc bing m6i truong bien da tao nen mgt he th6ng dau khi hoan chinh sinh - chira - chan.

Mat cat trim tich phu he ting Tra Tan duai, can nghien ciiru chi tiet hon niia de co thi phan djnh dugc cac don vj dja ting nh6 hon nham lien ket cac tang chiia va tang chan dia phuang.

Tuang hiiu co (bao gIm ca thanh phan hoa thach) trong cac thanh tao tram tich thuoc phu he ting Bach H6 tren ehu yeu la kerogen loai II - I cho kha nang chuyen hoa thanh diu - khi va diu. Phu he ting Bach H6 duoi chi dong vai tro la cae tang chira dja phuong va quy m6 phan b l trong kh6ng gian kh6ng Ion do thanh tao chii yeu trong dieu kien dong bang aluvi.

Phu he ting Tra Tan tren chiia ham lugng vat chat htru co kh6ng nhieu, kerogen chu yeu la loai I - II. Phu he tang nay dong vai tro tang chiia la chu yeu, nhung sir phan b6 ciia tang chan se co quy m6 nho do m6i truong thanh tao chii yeu trong dieu kien dam ho nuoc ngot.

Phu he tang Tra Tan duoi (tap dia chan D) chiia chii yeu la kerogen loai I voi sapropen th6ng trj trong mat cat co xu the chuyen hoa chii yeu thanh dau. Tap tram tich thuoc phan tren ciia phu he tang Tra Tan duoi dong vai tro tang chan do thanh tao chu yeu trong m6i truong vung vjnh nen co dien phan b6 rong Ion hon.

Tren pham vi mo Su Tir Den, vang mat cac tram tich ciia he tang Tra Cu dugc lang dgng trong m6i truong chii yeu la d6ng bang song. Cac tram tich thuge phu he tang Tra Tan duoi la tang sinh chii yeu ciia be Cim Long tao ngu6n hydrocarbon chii yeu di chuyen true tiep vao mong phong hoa nirt ne truoc De tam.

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