Tap ctil BIA CHAT, loat A. s i 320.9-10/2010. IrJ-lO
TIM THAY BAO TU* CONIOPTERISWK PHAN HOA CLASSOPOLUSTRO^G HE TANG HON GAI
T4J CHtJA DONG, YEN Tif
'BOI PHO MY, ^DOAN NHAT ntirdNG, 'HOANG DINH KHAM, 'NGHIEM NH^T MAI, 'NGUYSN CM HlTCJNG, *NGUY^ VAN HO ANH
'HgiBfatA&ThanhphSHdChiAi&A;
^Vipi Khoa hqc Bia dtSlva Khoang son, Thar^XuanHaNpi:
^HQiC6sinhDiat&^ 6 Phgm N^i Lao, Ha Ngi;
''Tdng l^i Dfa cha Vi4tNam, 6 Phgm NgS L&i Ha Ngi
Tomtm: OYhiTi^ tnmgcac tram tich chtm than thuQc h^ tSig Hm Gca tudi Trias mugn, Nori-Ret, viia tim Att^ mQt t^ App Bao tirphSn hoa trong do co Coniopteris va ClassopoUis tidi Jura
Cdc tram tich chua Bao tic phan hoa kS tren la cdc I6p bpt ket mong xen trong nhang trdm tich hat tho, cMyiuldcu&ikst, day khodng 300 m,f}hdn bo tit ch&a Bdo Sdi den chiia Ddng n&n tren ^nh niii Yin Tu Chung tht^ phdn tren cimg cua cdc trdm tich chOa them a ddy. Chung da dupc mdldla "CuQi ket Cfdia Ddng, tuoi Jura sdm ". Nhu the h$ tmg Hon Gai ttp Yen Tic co bi d^ U50-1300 mvdcd tudi jyias muQn,Nori'Jwasdm(T^-Jihg).
L MAT CAT H$ T A N G HdN GAI tf V O N G CHIJAD6NG.YeNTt>
Trong bii niy, "Cu^i kit ChCia D6ng"
\k ten gpi nhOng cu$i ket v i t r ^ ttch xen k€ thuOc phan tr^n cung cua h$ t ^ g chi^
than H6n Gai, hi^n dug'c coi l i cd tuoi Trias mu$n, Nori-Ret (Tan-r hg), phSn bo A Y6n Ti^. L6p tdun tfch hgt th6 niy cdn 1$ ra nhiiu noi nhu 6 Bk) Dii, t^o nkn dai Bao Dai - Y6n Ti^. 6 Con Son, sau din thd N p y i n TrSi' c6 su6i nh6 cung 10 cupi kit hao hao " Cu§i kit Chiia Dong".
M§t cat h$ t ^ g H6n Gai d diy 1$ tvr nhi6n tren dudng mdn tO: suoi Giii Oan' qua chua Hoa Yen, chiia Bao Sai, den
Tuang truyen rdng sau khi dgc "Binh Ngo Dgi cdo ", Nguyin Trai dd lui vi dn ddt nai nay. Thtdc khixdyrawdn "14 Chi Viin". thi thodng NguySn Trai ngdi cung Thf I^ ddnh cd, uong ncpu, ngdm tha & suoi ndi tren!
'M^ cdt ndm trong phgm vi ddt Phdt thudc Thien phdi TrOc Ldm. Yen Tu. nSn tin cdc chiia m6td,xdc dfnh cdc vf tri theo sa do di tich - thdng cdnh chiia Yen Tir trong sdch Chiia Yin TO; ciia tdc gid Trdn Truong 2007. Nxb VSn hoa Thong tin. Hd NQI
' Mdt cdt chu yiu sir dung tdi li^u cua Nguyin Cong Lupng (2001). co dieu chinh vi4c ph&i chia. di tiin liin hi vdi hai mgt cdi Ndng San vd Sudi Bdng trong bdi ndy.
chiia D6ng tren dinh niii Yen T(r. M§t cit^
cd thi chia Iim 3 phin;
Phdn dtt6i: Nam bat chinh hgrp tren(?) h$ tAng Tan Mdd l i cu^i kit co sd, cuOi nhiiu thanh phin, cit kit, bpt kit, dd phiin s6t xiin, th^u kfnh s6t than, than xau. Diy khoing 200-300 m;
Phdtt giua: g6m 2 t§p:
^ - T4p 1: Chuyen tiep tic ph4n dudi 16n din do^n chua M0t Mai, d d$ cao 600 m, ciing do cao vdi chua Hoa Y6n g^m cit kit, bOt kit, s ^ kit xen ft sdi kit v i khoing 10 via than cdng nghidp, mSi via cd chi&i diy tit I din 12 m, cd noi diy
den 25-28 m Ttdm Hch cfl tmh phan nhip chiia di lich Thyc vjf Taeniopterisjourtfyt.
Podozamiles lanceolalus, Neoealamiles hoerensis, PlerophyUum eontigtatm, Goepperlella mieroloba, v.v.
... Day khoang 400-500 m.
- Tgp 2: phan bfl tft ehua Mflt Mai din chua Bdo Sdi d dd cao 800 m, gom eugi k ^ san kit ftach anh sang mdu, xen cat k^t hgt ftd d t a min, set than xam den, tliau kinh than, chua it hda lliaeh Thyc v j t Ddy khodng 150-200 m.
CMk ddy phdn giiia khodng 550-700 m. Sau chiia Iloa Yin', trta dogn dudng mdn sang ehua Mdt Mdi, da thn ftdy mflt so dgng hfla thgch Thyc vat g6m: ' Neoealamiles sp., Equiselites sp., Podozatnites sp. (NgMem Nhjt Mai xdc djnh) ftuflc h | "Thyc vjt Hdn Gai" tu6i Trias mufln, Nori-Ret.
Phin trin: Xem nhu bdt iht tft chfta Bdo Sdi din dtah nui Yta Tft, gom cdc tdim tich hgt ftfl, chft ykii id cu$i kit, nin dugc ggi Id "Cufli k i t Chfta Dong", ddy khodng 300 m. Trong dogn tft chfta Hoa Yin din chfta Bdo Sdi, dd ftu thjp 2 mau phJn dch Bdo tft p h ^ hoa (BTPH).
Miu YT.l \ky d pMa sau chfta Hoa Yta, dftng vdi diem cd hda thgch Thyc vjt vfta nfli uln, khflng cfl BTPH. M I U YT.2, \iy it Idp sit dudi cufli kit ehua Bfc Sdi cd: Granulatlsporites sp., Lycopodium macrareticulatttm, ClassopoUis sp., Lygodium echlnaceum, vd nUlu bdo tft nam (?). Mau YT.3, lay d set than gan chua Bao Sai cfl:
Granulalisporlles sp., Coniopteris sp., Uiottililes sp., Aneimla sp.. Miu YT.4, liy d cong tnidng xay dyng tugng ddi Trdn Nhdn Tflng, cdch chfta Dong khoang 80 m v i pUa nam cd: Inapenuropollh
SIX, Araucariacites sp. vd nhiiu bdo tft njm(?).
Nha cfl sinh Nguyin Dftc Tftng, ngudi da xac dinh BTPH, ed nhjn xlt: 1. Ba mau (YT.2, YT.3 vd YT.4) chfta khdng tftiiu BTPH. Nhung dgng dd gjp ftudng thdy trong cdc ttam tich cd tufli Jura- Creta; 2. Hai mdu (YT.2 va YT.4) cftn§
clifta Miiiu Bao tft njm, cho ftdy ed fti tram tich d mau YT.4 la sdn pham phong hoa hj trim tich d mdu YT.2; 3. Cfc man diu chfta rdt Miiiu BTPH M|n dgi va D | tft, nhung nhilng dgng nay dd b) logi trft khdi kit qua; 4. Sy cd mjt Idiong nhieu cfta phdn hoa Khda tft, ddc bijt la chua gdp dgng ndo cua plidn hoa Bi tft, cho thdy khd ndng cfc tram tich d cdc mau YT.2, YT.3 vd YT.4, tftc Id ftugc "Cufli kit chda Dflng" cd Mfli Jura (xem Bdn dnh).
Tflm lgi, mjt cdt cdc trdm tich chia than d Yin Tft tuy duge chia Idm 3 phdn, nhung vi trong phdn dudi ehua tim dugc hda tligch, nin hai phdn dudi vd giiia dya vdo hi6i hda ftgch Thyc vjt xep hi&
chung Id Trias mugn, Nori-Ret. Cfln phdn trin, g6m cdc tram tich hgt ftfl, dya vdo hda ftgch duge dinh tuSi Id Jura sdm (J|).
Nhu vjy, mjt cdt h | tdng Hfln Gai d dJy ddy 1150-1300 m vd cd tuoi Trias mugn, Nori - Jura sflm (Tjn-Ji hg).
. IL U i N H f MAT CAT HE T A N G H 6 N GAI VUNG CHUA D 6 N G , Y 6 N TU' V 6 l T R A M T I C H CHl/A THAN H$ T A N G N 6 N G SON
NMiu nhd dja chat dd nhjn ftdy cd cdc diim gi6ng nhau gifta cdc ftitai tich chfta than Trias ftugng d hai vftng, Yin T i d Uflng Bi, Qudng Ninh miin Dflng Bdc Bfl vd Nflng Son d Qui Son, Dgi Lflc, Qudng Nam, miin Bdc Trung BO. Chung deu Id tram tich lyc dia, cung cd tjp hgp hfla thgch ftyc vjt ftuflc " h | Thyc vjt Hfln rL^ih^/^ S T J I ' w f i f * ^ ^ ' "^f "^ «"• "--^ « * * , Tdng - vi vua
"•^o^ ^T^ Tun, hanh. Igp nen Thiin phdi Trie Ldm Vi4t Nam.
cung
4
uai , moi inas muon, rsron-Kei, cung co lo^i than anthracit.
Mat cit c ^ trim tich chiia than d Nong Son dugc mo ta ttJr Thanh M^ din rad than Ngoc Kinh (Nguyin Chi Hudng, 1983; Bui Phii M% Hoang Dinh Khim, 1999). Vdi tu li6u va nh|n thuc mdi, chung tdi tiiay mit cSt he tang Ndng Son ciing cd the chia thanh 3 phin:
Phdn dif&i: dugc chia thanh 2 tap:
- Tap J: Nam bit chinh hgp tren da vdi Paleozoi Thanh My la sdi ket co sd, thinh phin hat sdi chu yeu l i thach anh, quarzit, it ci^i granit gjdng granit D ^ Lgc, dp mii trdn l^m, xi ming Ii cit kit mau nau nhat; diy 10-15 m. Ldp ca sd nay diuyln l&n cit ket, bgt kit miu niu nh^t, phin ldp diy, ft Idp xen san ket. Trong mdt sd ldp k?p bOt kit mdng g^p cic di tfch thvrc v|lt bao t6n xSu va l i nhihig hda th^ch khdng quen b i i t Day 155 m.
- T^ 2: Sdi ket, cu§i kit xen ddi ldp cit kit h^t nhd, b$t kit miu niu nh^t, phin ldp diy v i trung binh; diy 205 m.
Tnng i^iln n ^ chua tim thiy hda th^ch.
Be diy chung ji^ dudi khoing 360 m.
Pkin giSu: g6m cit kit h&t v i a din tiid, miu xim sing, phin Idp mdng den v ^ ddi ch5 cd phan Idp xien, xen vdi bgt kit, di phien set miu xim slim, it thiu klidi sdi ket tiiich anh h^t thd. Phan niy cd tii 3 din 5 via than cdng nghi|p, cd noi via diy din 30 m.
Cic Idp s6t than gin via than thudng chiia mgt so hda t h ^ h Thyc v§t thu$c "h?
Thyc v§t Hdn Gai" g^m Claphropteris obovata, Dictyophyllum nathorstii, Podozatnites distans, P. lanceolalus, PtUozamites vennis, Goepperlella vietnamica, Cycadocarpidium erdmarmi.
Cladophiebis raciborski. v.v. ..., tuoi Trias mu$n, Nori-Ret (Nguyen Chi Hudng suu tip v i xic djnh, 1983).
Trong nhiing ldp da p h i ^ s^t xen tiong cuoi kit, cat ket hat thd trgn v i dudi mgt via than m d i ^ nim ngay tai bd sudi Khe Tre, each cua sudi 150 m, cd nhiiu hda thach thuc vat: Thaumatopteris remauryi, Neoealamiles hoerensis, Clathropteris mongugaica, Cladophiebis (Fodites) shensiensis, Equiselites sarrani.
Squamiofolium dictyonervum, Palissya brurmii, Yuccites vietnamensis, Taeniopteris cf. ensis (smi tap Bui Phii My, Hoing Dinh Kham, 1999, Nguyen Chf Hudng xic dinh).
Ciing tai ffiem nay, nim 1983, Ngj^fln Chi Hudng ^ suu tap v i xac djnh gdm cac v ^ in tfiuc rat Neoealamiles earrerei.
Thaumatopteris remauryi, Clathropteris longffobtOa. Dictyophyllum nathorstii D.
muensteri, Podozamites lanceolalus, P.
reinj, Pter(^hyUum bavieri, P. sp., Hausmania sp.. Fergtmiella sp. v i Biii D ^ lliang nim 1981 tim tfiay p ^ hoa Khda tii ClassopoUis sp..
B I diy phan ^ i i a 10 theo dudng d td viing md than Ngge Kinh 350 m v i theo su6i Khe Tre tir cfta suoi ngugc len 150 m. Be diy chung l i 500 m.
Hai phan dudi v i giOa dua vio tudi hda th^ch thuc v|t dugc xip tu6i Trias mugn, Nori-Ret.
Phdn trin: Phan tr&i chuyin tilp tii phin ^Oa len, gSm cac tram tfch hat tfid hon, chu ylu l i cuOi kit chiia hda th^ch ClassopoUis sp. v.v. ... phin b6 tii vit 10 ben bd si^i Khe Tre, cich cua su6i 150 m, len din dudng phin thuy. Diy 360 m.
Tiudc diy Biii Ph6 MJ d i tiing so sinh cugi kit Khe Tre vdi cu^i kit Bio Dii - Yen Tli, m i nay ggi Ii "CuOi kit Chiia D6ng". Trong phan niy, tren m$t cit khong cd hda thach, nhung t^i dinh niii Bin Cd, trong cuOi kit tuong ty;, d i tim dugc hda tf^ch tfiyc v|t, v L Ii nhflng d^ng tfiuOc "hO Thyc vat Hdn Gai".
Tft vi|c mdi tim ibky BTPH Coniopleris va ClassopoUis tiong cufli kit Chua D ^ g is Yta Tur, lita h | vdi sy cd mjt cfta ClassopoUis trong trdm tich chfta than Nflng Son, chftng toi ding nhjn tiiay nhu Bfti Dftc Thdng (1981) ffl viet: 'Tuy sfl lugng man phan tich cdn it di (3 mdu), song so lugng ldn phin ClassopoUis cho phip suy^ ngM budi: ddu v i yeu tfl Lias (Jl) d phdn trta cftng ciia ttdm dch chfta ftan Nflng Stm".
Nhftng ngMIn cftu cM tiit ve sau ndy chdc chdn s€ cfl ftem tdi lita lam sdng tfl ftem'vdn de nay.
II. I J £ N HE V()l CAC TI^AM TtCH CHI>A THAN SUA BANG
Dya vao mjt cdt chuan SuSi Ldo, Vu Khftc, Nguyin Vinh (1967) da cUa h | tdng Su6i Bdng ldm 3 phdn :
Phhi dudi gim 2 tjp:
-Tdp I: Bgt kit, dd phiin sit xdm phdn Idp, cdc ldp kfp dd vdi sit xdm, dd vdi vd sd, cdt kit vfli sd hin, xen cdt kit vfli cd ' bda thgch ChJn riu: Halobia distincia, Zitlelihalobia sublaevis, Gervtllia shaniorum, Anomia mtpengensis, Palaeocardila singularis, Mesoneilo framageti, vd Cftc dd Discattopiles
noricus. Ddy 212 m.
- Tdp 2: Cdt kit hgt mjn, cdt kit thgch anh, phdn Idp vfta cd mica, ldp kep bflt kit xdm, tiln dd Id cdt kit da khodng sdng mdu, ehlra vyn ftyc vjt, rii din cdt kit xen cdt kit chfta cufli hgt ftfl, sfli kit, cufli kit cd hfla thgch: Zitlelihalobia lenuiseostala, Burmesia lirata, Coslaloria (Ntfiengocosia) napengensis. Ptdaeoeardita singularis, Prolaria sollasi, DenlUucina mono. THiphorus angutahts, Langvophorus goraiMt. Ddy 425 m.
Ting chiiu ddy phdn dudi Id 637 m Phin giira: Bflt kit xdm, phdn Idp
^ n g , ftudng chfta vyn ftyc vjt, xen cdt H xdm. It Idp kep sit kit, sit than xdm
den va vai via than gdy, chuyin Iln trta cat kit Id chft yiu. Hda thgdi dgng vjt trong phan ndy gflm nhftng dgng bita vd nudc lg: Gervillia cf. ir^ata, Isocypritut ewaldi, Viettutmicardium nequam, Uniotites damdutwmis, v.v. ... vdi ftyc vjt:
Clathropteris meniscioitks, Dictyophyllum Tutthorsli, "Glossopteris" indica, Yuccites vietnamensis, Neocalainites hoerensis, Goepperlella mieroloba, v.v.... Ddy 270 m.
B i ddy cfta hai phdn dudi vd gifta tgi mjt cdt khodng 937 m.
Trong bdi bdo ndy, hai phdn dudi vd gifta c i a h | tdng Su6i Bdng, d mjt cdt Su6i Ldo, da dugc ggp Igi ftdnh mflt phan, vi chftng deu 14 trim dch biin, diu ed tuii Nori. Phan Bin vdn Id phdn cfl than, hfla ftgch thyc vjt vd Id tram Hch a lyc dia tuii Ret. Diiu chinh mOt chftt nhu
• fti d i de liln h | vdi cdc h? tdng Nflng Son va Hdn Gai d Yin Tft.
C vftng Mudng Nhi, tdy nam thj ttdn
• Lai Chdu cfl, nay thujc dnh Di|n Bito, mjt cdt cfta h | tdng Suii Bdng, Ifl fteo suii Njm Peng, vftng HuOi Sdy (Bfti Phft My, Dinh Thi Tdn, 1971) eOng cfl dft 2 phdn nhft d Su6i Ldo. Nhung d ddy cfl cugi kit co sd rfl rdng ndm bdt cWnh hgp tien granit cd tuii Pemii(?), ngay bin trta cufli kit CO sd Id dd phiin sit chfta:
Halobia norica, Zitlelihalobia obruchevi Plagiostoma nuiloensis mii Nori. Phdn tren chfta hda thgch ftyc vjt vd cdc hfla thgch biin, nudc Ig, nudc nggt cftng cdc via than mflng, tuii Ret. Cd khdc Id b i ddy mjt cdt gidm nhieu so vdi mjt cdt Sufli Ldo.
Phin trim Djc biflt, ciing nhu d Yta Tu vd Nflng Son, ehuyin d i p trin phdn chua ftan cd mflt khfli lugng ttfci dch bdt ddu Id:
- 7<^/: Sit kit m i l xdm xen cdt kit hgt mjn, phin Idp. S « vd vyn xen nhftng ldp than mflng, trong sit kit cfl hda thgch ftyc vjt: Coniopleris clavipes, C ^ , Equiselites
s p , K cf. arenaceus, Clathropteris menicioides. v i h d a ihach dong v a f Unionites damdunesis. tren ^ la set k i t x a m den, hat min, x a m vang, phan dai mdng, xen cat k i t phan ldp day c o chiia Unionites convexa, day 6 0 m .
ijij - Tap 2: Cat ket hat n h d d e n vira, cd mica, ijijj phan Idp d i y va set ket chiia k i t hach xen cat
%^ k e t cd di tfch t h u c vat: Pterophyllum aff.
contiguum, P. sp., Cladophiebis sp.,
^^ Olozamites cf. indosinensis, Neoealamiles earrerei, N sp.;day 100m.
^ - Tap 3: SU kit phan Idp, xen hot kit
^^ xam, phai Idp mdng, cat ket xam. Trong cat
"'I kit cd hda thach dpng v^t: Cardinia cf
\^ nachamensis. Unionites damdimensis, M^^^ Estheria sp., Thracia sp.. Day 130 m.
j ^ ^ ^ l - Tap 4: Set kit mau xam, hat min, cau
^^KF tao kit hach, phin Idp vCra, xen bpt ket xam,
^ ^ ^ set kit niu. Trong s6t ket cd hda thach dpng vat: Cardinia ovoidae cd ldn, Unionites iii damdunensis. Day 90 m.
^^ - Top 5: Cat kit xen san ket, bpt kit phan , dai, set kit miu dd, ddi khi cd nhiing Idp '™ cugi k i t Trong set kit cd: Unionites '"'• convexa, Estheria sp.. Diy 170 m.
ijit . ^ L, BS d i y chung ciia phan nay la 550 m.
Iiii Theo nhi cd sinh Nguyen Ba Nguyen, thi
\k suu tap thuc vit, trong dd cd Coniopleris H clavipes, C. sp., cd tudi Lias (Ji).
* Nhin chung, trong cac t r ^ tich cd miu
"^ dd, phiic he hda thach gin giJi vdi Jura. Song
; Vii Khuc cd luu y sir cd mSt cac dang dia f phuong kich t h i ^ nhd nhu Unionites ''' damdioiensis, U. convexa thudng gip trong
trim tich chiia tluui Trias mupa I" Tuy v4y, mpt sd Chan riu kich thudc ldn
*• nhu Cardinia ovoidae. C nachamensis cd
^ lunh d^ug chung ^in gui vdi Cardia philea vi C. giganlea tudi Lias (Ji). Cd nhieu hda J, th^ch nudc ngpt nhu Estheria sp. nhung trSn I mit cit, chiing nim tren Coniopteris v i nim
xen ldp vdi phiic he hda thach mang nhieu
ylu td Jura, nen phan 550 m tren ciing cua mat cit Sudi Bang, trudc day da dugc xep vao mdt phan vi Ji (Biii Phii M^, 1971), nay xin xem Ii phin tren ciia he tang Sudi Bing (J,).
Mat cit he t§ng Sudi Bang theo bai bao nay cd chieu day khoang 1500 m va cd tudi Trias mugn, Nori - Jura sdm (J^n - J| sb).
rv. NHANXETVAOeNGH!
1. Tir viec lim thiy BTPH Jura d cudi kit Chiia Ddng, Yen Tii, din viec lien he vdi cic he ting Ndng Son va Sudi Bang, ta thiy ring: ca 3 mat cit Sudi Bang, Ndng Scfn va Hdn Gai d Yen Tii, tieu bieu cho cac trim tich chiia than d ba noi nay, tu trudc din nay diu dugc xep tudi Trias mudn. Nay, trong phin tren ciia chiing da tim thiy cac hda thfich Jura, cd the Ii Jura sdm (J|).
Tuy nhien, vdi cac trim tich Jura hg tii Ii?u cdn it, hon niia day la vin dl ranh gidi giira hai he Trias vi Jura d nudc ta v i ndi chung Ii khd, can th|n trpng. Vi thS, nen Iam chi tilt fad sung de tham dinh va cd ket tu$n chfnh xac.
2. Mgt van d e niia mdi p h i t sinh l i phai nghien ciiu xem moi lien q u a n giiia c i c B T P H Jura vdi h? " T h u c v|.t H d n G a i " trong thdi gian v i khdng gian dia chat.
3. Viec xip cic trim tich chiia than vao tudi Ret d he tang Sudi Bing cd thi l i phii hg^, nhung cdn tiiy thuOc vio ket qui nghien ctiu hai mit cit Ndng Son va Yen TCr, cung vdi viec nghien ciiu he "Th\rc vit Hdn Gai".
4. Nam 1995, Cat NguySn Hiing va nnk. da ap dung each phan chia h? tang Sudi Bang v i dua he ting Ndng Son tudi Nori-Ret len thanh loat Ndng Son v i chia tach bach ra 2 he ting: phan tren chiia than va hda thach \h\cc vit, l i hf ting Sudn Gifia, tudi Ret. Phin dudi chua cd hda thach, chua thiy than, Ii hS ting An Diem, tudi Nori.
4«
Chu gidi bdn dnh:
1. Coniopteris sp.
2. Aneimia sp.
3-4. Lycopodium macroreticulatum 5. Lygodium echinaceum 6-8. Leiotritetes spp
X 900
9-10. Granulatlsporites sp.
11. Araucariacites sp.
12. ClassopoUis sp.
13. Inapertieropollis sp.
14-15. Bio tli nim (?)
(Cdc tita bdn BTPHduge luu lift tgi Bdo t d n g - D i g e h t T p S ^ ^ i Ldo, HdNfl,
£>e c6 sue thuy€t phuc cin tim kiem hda thach d {diin dudi ciia m ^ cit Ndng Son - turc h? ting An Diem, va k l c i jAan dudi d m^t cit YSn TCr (theo cac tic gii bai bao niy), hiSn nay dang xip tudi chung l i Nori-Ret
5. N ^ e n ciiu 1^ hon cac trim tich chiia than Ndng Son, khdi^ pihii dii pbac vu dan diuan ve miit khoa hgc, m i cdn \i tai n^iyen kboing sin cung vd ciir^ quan ^^yng, Ist^ng dii vi dian m i cdn vl quii% uranl
Than Ndng Son d i dugc khai thic tii lau, nhung cU thudng xa hen quan vdi urani mdi dugc phit h i ^ sau ngiy di6ng nhat dit nudc ^ o i n 501, LBDC 5, Hoing Dmh Khim, 1978 v i Doin 500, Ld BDDC. HuSnh Trung, 1979). Nghien ciiu d diy v l mat khoing sin v i bio v$
\ mdi trudng deu Ii can thiet.
Nhin dip bii bio dugc cdng b6, cic tic gii chin thinh cim on Hdi C6 sinh dia ting, Vi0n Khoa hgc Dia chit v i Khoing sin, nhi c6 sinh Nguyin Diic Tiing ^ xic dinh hda t h ^ h v i 1 ^ bin inh c6 sinh, TS T9 Hda Phuong d i tgn tinh giiip dd dk cd dgt "hinh huong" khio sit c^a diat rit thA vi niy v i d3 dgc bin diio bii bio, dinh gii cao nhChig phit hifn mdi ciia t|qp the tic ff&.
Bbng ihin cung gdp thSm ^ Idin qu^ biu nhfim hoin thi$n n$i diu^ hinh biy.
VANUEU
1. Biii Due Thing, 1981. Tim thiy phin ClassopoUis trong trim tich chiia than Ndng Son. Dia chdt. 152 : 23-27.
HaNCi.
2. Bid Phi^ M^ (Cha bien), 1978, 2005. Dia chit v i khoing sin td Lio Cai - Kim Binh (Thuyet minh ta bdn dd dfa
chdt vd ldu}dng son Lao Cm - Kim Binh ty 14 1:200.000). Tdng eye Dja chdt, 1978;
Cue Dfa chdt va Khodng sdn ViSt Nam, 21)05. Hd mi
3. Cat Ngnyin H ^ g {Chu biin), 1995. Bio cao Bja. chit v i khoing sin nhdm td Ndng Son, kem theo Bin dd Dia chit v i khoing sin nhdm td Ndng Son ty 1? 1:50.000. Lmi trii Dia chdt. Ha Ngi.
4. Dovjikov A.E. {ChU bien), 1965.
Geologia Sevemogo Vietnama (Dia chit mien Bic Vi?t Nam). Tong ct4c Dja chdt, Hd Noi (bdn tiing N^a); 1971: Nxb KH&kr. Hd Noi (bdn tieng Vi^t).
5. Hoing Dinh Kham {Chu biin),, 1978. Bio cio Kit qui thfim dd kiem tra md than Ndng Son. Luu trii Dja chdt (s6 ltfutriiT.183),HaNQi.
6. Hn^iih T n m g , NguySn BlSrc Thing, Phan Thifn, Ngd V2n Khai, B$
v a Long, 1979. C ^ thinh tao xim nl4p granitoit khoi D ^ L$c, Sa Huynh, Chu Lai. Dia chdt vd Khodng sdn VN; 1:159- 163. Lien dodn BDDC. Hd Ngi.
7. Nguyen Chl Hvdng, 1983. Gdp thSm tii lif u th\rc v$t cho di$p chiia than Ndng Son. Dja chdt. J59:22-26. Hd N^i.
8. Ngnyin Cdng L v ^ g (C/tii biSn), 2001. Dia chit v i khoing sin td H^ Long (Hdn Gai). (Thuyit minh ta bdn dd dfa chdt va khodng sdn Hg Long (Hdn Gai) ty l^ 1:200.000). Cvc DC vd KSVN, Hd N0i.
9. VQ Khnc, NgnySn Vfnh, 1967. Vl mgt vii m$t cit dia chit v i svr phin chia chi tilt ting chiia than Su6i B ^ g d Tiy Bic Bp. Dja chdt. 71-72:14-17. Hd Ngi.
SUMMARY
Finding of fte spore O>niopt&is and pollen ClassopoUis in the Hon Gai Fonnation in the Ddng Pagoda area, Ydn Tin Mt
Siii Phil My, BodnNhgl Truing, Hodng Binh Khdm, NgMlm Nhai Mai, NguySn Chi Huang, Nguyin Vdn Hodnh Recently, in fte Yta Tu Ml, a spores and pollens assemblage containing fte Jurassic genera Coniopleris and ClassopoUis has been found in coal-bearing sediments belonging to fte Hdn Gai Formation of Late Triassic, Norian-Rhaetian age.
The sediments containing fte above spores and pollens consist of siltstone interbedded wift coaise-grained beds, mainly of conglomerate, about 300 m ftick, disuibuted ftom Bdo Sdi to Dflng Pagodas, lying in fte summit of fte Yta Tii Mt. They belong to fte uppermost part of fte coal-bearing section of this locality. They have been described as "Chda Dfing Conglomerate, of Early Jurassic age". So, fte Hon Gai Fonnation m fte Yta Td Mt has a thickness of 1150-1300 m and has an age of Late Triassic - Early Jurassic (Tan-Ji hg).
Ngudi biin I4p: GS. TSKH Vu Khuc