T » i A i D l A Q l A T I . M ( A sA 321. 11/301(1 rr ^t-tfl
KET QUA DO ANH DIEN LUAN GIAI QU^NG THIEC VA KIM L04J HBEM LITHI 6 VUNG LA VI, QUANG NGAI
. N G U Y S N DIjrc QUAN, PHAM VAN THONG NGUYEN CANH NHO, TRAN HOU TRONG, NGUYfiN VAN SINH
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Kit qui flii cflng Dfi in "Dinh gii ttiln vgng qujng ttiilc v i kim logi Mim (Ta, Li, Be) vung La Vi, tinh Quing Ngii" d i gidp phit Mfin v i xic djnh 40 flian quing vi fliin khoing pegmatoid chua liflii vi fliiic, ttong dd cd 20 flian qujng Li-Sn v i Sn dgt him lugng eflng ngMfip. Cac phuong phip ky fliujt dugc ip dyng bao gim: do vfi dja c h i t ttgng sa, trie dia, dja vgt ly, khoan, khai dio v i lly mlu.
Phucmg phip dja vjt ly gftp phin quan trgng ttong vific (finh hudiig, fliiit kfi cic vj tri khoan Bii viit nay gidi ttiifiu kit qui do finh difin dl lujn gifii sy tin tai ttieo cUfiu siu cfic ttifin qujng ttiilc vi kim logi Mim (Ta, Li, Be) ft vdng La Vi, (Juing NgSi.
II ( ^ T R O C DjA CHAT VCiNG QUANG VA BAC B I f M m A N QUANG
Trfin difin tich phan bo qujng ed mjt cic flifinh tgo: 1/ Dfi pMin kit tinh ttiugc phto: hfi Kan Nack (A-PP kn), bao gim d i pMIn ttigch anh - 2 mica, d i pMfin ttiach anh - biotit gneis biotit d i pMin ttiach anh - felspat.., cic d i niy ehinh l i mfli tiuftng chua qujng; 2/ Cic ttifinh tao bazan tougc hfi ting Dgi Nga (N|' dn), ttiuomg tgo nfin cic chdm nhd, bao gim'
plagiobazan, bazan olivin ciu tao djc sit 3/ Gramt 2 mica ttiuflc phuc hfi Sa Hujnh (G/T,.2 sh), lg ra vfti difin tich khflng dfing kfi, bao gdm ehu ylu l i gramt 2 mica, granit biotit gramt sfing mfiu hgt nhft-vda.
Quing ft diy chu ylu Ii logi Unh mgch pegmatiiid chiia kim logi Mfim (lithi) vi flnlc. Kfit qui do mlu fliam sfl difin cho ttiiy dien ti* suit cua pegmatit chira qujng fliay dli tir 889 den 7376 n.m, ttimg btoh: 3046 Q.m; difin txij suit cua d i pUfin fliay dli Hr 160 din 1100 n.m, ttung binh: 588 a m . Cic mgch qujng ed ctoeu diy ttung binh tir 0,6 dfin 4,8 m, phfl biin Men togmg biin dli greisen hoi!
Him lugng Li v i Sn ttung btoh ttong cic fliin qujng rit khong dfiu; ham lugng Sn fliay doi tii 0,1 din 0,91%; him Iugng U2O tir 0,39 din 1,44%.
MSt cat dja chat ttr ttfin xuflng cft djc difim nhu sau:
1. Ldp dit phu: cd cMlu diy 0,4-1,5 m, tiling binh: 1,0 m. Thfinh phin bao glni set c i t dfim, sgn bft roi.
2. Lap d i pMln kit tinh hfi ting Kan Nack bj phong hoi v i bin phong hoi, cd be day fliay doi tir 2,5 dfin 15 m, ttimg btoh khoing 10 m.
3. Lftp d i pMfin kit tinh tuoi cdrng hfi ting Kan Nack.
4. ITian mach pegmatit chiia qufing xuyfin cit tiong dfi [dnfin kit tinh ciia he ting Kan Nack CO be (li^ tir 0,6 din 4.8 m, trung bulk 0,7 to, gdc cim phfl bi&i: 50-85°.
• . cor S d A P oyNG P H U O N G P H A P K ? THUAT
1. Co> sft ly thuyit v l phuong phip Phucmg phfip inh difin Ii phucmg phip difin thuc hifin trfin mfit he da cyc dugc bfl trl, sip xfip Uieo mOt quy ttinh da dugc djnh hudng. Phutmg phip niy da dugc nMfiu nuftc trfin thfi gifti sd dung rfit co hifiu qui d l tim kifim, fliam do khoing sin ran, nuftc dudi d i t ^ a chit cflng trinh va nghifin ciiu mfli tnrftng, ... d nttdc ta, tiong nhdng nam gin djy cung da bit diu sd dung phuomg phip niy ttong cflng tic dieu tia, dinh gii v i fliam dft khoing sin.
Co sft chinh cua phuong phip dya ttfin bii toin mfl tfi bfti phuong trtoh vi phin:
- .sIaem_ve_bMih_th4L.t**^
Div(ngradU) = -I8q (I) ttong dd: a = gii tii nghjch dio eda difin ttft suat (dO din difin cua mfli tiuftng); U = difin thfi phfin bd ttong moi tnrftng; I6q = mo t i nguin dicn.
KM mfli tiuftng cft cfiu ttiic phiic tgp phuong tiinh (1) cM cd flil gifii dugc ttieo phuong phfip sl. Quy ttinh ip dyng ttiuc tfi vi pho bifin nhit tofin nay 14 do dac va phfin tich flieo toyln 2D.
Vific phfin tich tii lifiu do inh dien tiiyc chit la giii bii toin ngugc; dd l i qufi ttinh cyc tieu hoi him dft Ifich btoh phuong tiimg btoh giOa gii ttj djen ttft suit bifiu suit bilu kiln Unh toin ttfin mfl hinh K ttiuyet cua cung ttiyin khio s i t Ttuit toin nay cho phfip IJp eic chuong tttoh tUi to dOng ttfin miy tinh, vfti cfic phin mem nhu RES2DINV, RESK 1P2DI
Do nhOng djc diim ve hmh fliii ttifin qujng, djc diim v l mjt cfit dja chit v i do difiu kiOn tiip dia l i t khft khin nfin dfi sii dyng hfi fliifit bj 4 eye d l i xiing Wenner ( W ) d l d o v d i a = l 6 - 1 3 0 m , n = I .
IV. P H A N TlCH K C T QUA DO A N H BI$N 1. Tuyin T.SOB
Tuyfin T.50B do inh di?n ttfin dogn to cgc -140 din 0 (140 m), ttfin mjt tai cgc - 110 da bit ggp ttian quing TQ.21a tgi hio H.273. 0 hio H.273 bat gjp mgch pegmatit nam dufti Iftp phd day khoing 0,5 m. Mgch nay chda lepidolit v i cassiterit xam tin, cd chifiu ddy bifin dfli tir 0,4 den 1,0 m xuyfin cfit ttong d i phiin ttigch anh - biotit tgo ranh gifti vdi dfi vfiy quanh khi rft ring, toi nim- 10-20^25-20°.
Giii bii toin ngugc ttieo chuong tiinh RES2piNV cho to mfl Mnh lit cit dijn ttft suit ttfin dogn toyln nhu sau:
1. Lftp difin toi suit cao (>3.000 Om), phin bo to ttfin mjt din dO siu khoing 15 n t Idp niy lifin quan dfin d i phiin ttigch anh - biotit phong hoi, bin phong hoi, djp vft nut nfi mgnh, khfl, nfin difin tift suit cao.
, 2. Phan dudi sfiu cua mfl hinh cua lit cat difin ttft suit, eie duftng dfing tii difin ttft suit khflng nfim ngang nfin hinh dgng phte Idp ngang nguyfin fliuy eda ting dfi phifin khflng con ton tgi. 0 diy, ta fliiy ed 3 khdi nim ngMfing: khoi cd difin a(t suit cao {>1.000 n m ) nim k?p giOa 2 khii cd difin ttft suit fliap (<500 Qm). Ttah chit n^ifing lifin quan chjt chfi vfti qui ttinh uon nfip do hoat dOng magma, hoic hoat dOng kifin tgo d i Mnh fliinh cic diit giy, khe ndt Cic khe ndrt dut giy chinh li vdng tiip giip giiia cie khii ngUfin cdu, l i cfic yeu tfl tgo diiu kifin ttiujn lgi cho vific di chuyin v i tich to cie dung djch khi ttiinh - nhifit djch chda khoing hoi.
Vdi sy phfin tich va nhgn djnh nfiu ttfin va dua vfio djc diim. ttil nim cua ttifin khoing noi diu Id via (H.273), than quang T.21a cd ciu ttiic thufin lgi eho viec tao ddi ehua quang v i tin tgi sau. Tflng hop kfit qui phfin tieh v i nhan djnh, dS dfi nghi khoan tai cgc -80 d l xic djnh su tin tgi eda thin tiujng nay.
Kfit qui khoan lfl khoan LK.2 ttfin ttiyfin T.50B la da bit gjp Uian qujng TQ.21a ft dg sau 33,3-34,0 m; day 0,6 m.
Mgch qujng co mfiu xfim tiing phdt hong;
mica chua lithi dgng vfiy nhft mfiu ti'm hflng, phfin bfi khflng diu, dgng I; cic khoing vjt mau den hat mjn, xam tin thua, cd khi ning l i cassiterit
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Hinb I. Md hinh Idt cat 2.TuylnT^7A
Tuyin T.47A do inh difin ttfin dogn tii cgc -110 din -MO (150 m), ttfin mjt di bfit gjp flian qujng TQ.8 tgi cgc 0 ft hio H.I 19 vi fliin qujng TQ.7 ft cgc -HO tgi hio H.I55 v i H. 160. Than qujng TQ.8 nim ttfin, cd bl diy biin ddi t i 2,1 din 3,3 m., flil nira 190^75°; ttiin qujng TQ,7 nim dufti, cd bl diy ttiay dli tii 0,7 din 6,3 m, tiimg btah: 2,6 m. Cic ttiin qujng xuyfin eit di pMin ttigch anh, fligch anh - felspat - hai mica - biotit
dipn Ird suit tuyin T.SOB.
Mfl htah lit cit dien ttft suit ttfin doan toyen nhu sau:
I. Lftp difin ttft suit cao (>3.000 Qm) phin bo tii ttfin mjt din dft siu khoing 10 m; ldp niy lifin quan dfin eic d i phiin togch anh - biotit d i p t o l n thgch anh - hai mica xen kep d i ptofin ttigch anh - felspat phong hoi, bin phong hofi, djp vft ndt nfi manh, kho, nfin difin ttd suit cao.
2. Phan dufti sfiu cua mfi htoh eda lit cit d i ^ no suit fti tofin 2 khfii nfim gin nhau:
khoi cd difin tift suit cao (>2.000 Qm) nim
ft hfin tiai, cam vfi cfinh am va khoi co £?n lift suit thip (<20(^Qm) nim boi phii.
Tflng hgp kfit qui phan tich va nhjn dinh, dfi de nghj khoan tai cgc -25. Kit qui khoan l i 16 khoan Lk.5 da bit gap toin qujng TQ.8 ft do siu to 42,9 dfin 43,4 m, day:_0,5 m; qujng co man xim ving, xim tring, hgt nhft, cd ftanh phin
cua pegmatoid; phan n'ch mlu cho him lugng U2O ^ 0 , 0 9 % v i Sn = 0,12%. (3 lg khoan LK.5 bit gjp Uian qujng TQ.7 ft dO sau tft 54,4 den 55,1 m, day: 0,7 m; qujng cft miu ttang dye phdt ving, bj nut nfi, phong hoi mgnh, xim tfin ftua cassiterit hat nhft-imn, mau den.
Ddi chLte qufing dL/(3o6n theo kS'tqui do finh diftn Hinh 2. Md hinh Idt cdt
3.TuylnT.45A
Tuyin T.45A do inh difin ttfin doan tii cgc -120 din -1-8O (200 m), ttfin mjt dfi bit gjp ftfin qujng TQ.lOa 0-fin cfic coc -40 ft hio H.I08 vi -50 ft hio H.107. Than qujng TQ.lOa cft dgng mgch, dgng I, dgng phfin nhfinh, chuoi thiu kinh, cd huftng cim doc dfin die dimg, hoi nghifing vfi tiy nam (190-210^ 60-85°) vol chifiu diy to 0,5 din 14,5 m; trung binh: 2,4 m. Thin qujng xuyen eit di pMen cua hfi ting Kan Nack.
Gifii bii toin ngugc cho mfl hinh lit cit difin ttd suit ttfin doaii ttiyfin cho thiy
dien trd sual ttiyin T.47A.
cft 3 khii: khii co difin ttft suit cao (>500 fim) nim k?p gida 2 khoi cd difin ttft suit ftip (<200 n m i . Khfli ed difin ttft suit >
500 n m cing gin mjt dit cing vit nhgn.
Tong hgp cie kit qui phfin tieh vi lujn gifii, da dl nghj khoan tgi cgc -30. Kit qui khoan i l khoan LK.7 bit gjp thin qujng TQ. 1 Oa ft do sau to 45,1 dfin 45,8 m, diy:
0,7 m (LK.7/2). (Jujng miu xim tring, dgng pegmatoid giiu thgch anh bj greisen hoa, edng chic; xfim tin cassiterit hgt nhft-mjn vfti mjt dft thua. Kit qui phan tieh mlu cho him Iugng Li20 = 0,09% vi Sn = 0,l%.
Htah 3. Md hinh Idt cdt VKETLUAN
Phuong phap do inh difin cft hifiu qui tiong vific du doin su tin tai dufti siu cua cic ftin qujng thilc vi kim loai hilm ft vimg La Vi, tinh Quing Ngii.' Kfit qui khoan ft phin Iftn cfic vi tti phii hgp vfti kit qui phfin tich tii lifiu. Trong mftt s l truftng hgp, do ciu mic dja chit phuc tap dfti chda qujng cd bl diy nhd, khong dd de tgt) nfin sy khic bifit vfi difin ttft suit so vdi dat d i vay quanh, do dd md hinh dua ra thfi hifin khflng rfl dfti chda qujng, din din vific dy doin sy tin tgi Uifin qujng ttong tiirftng hgp niy cd phan khd khfin.
Vific phin tich, lujn giii kit qui do Jnh difin vfi sy tin tgi dudi siu cfic khoing sin nfti sinh ndi chung va khoing sin ftilc, kim logi Mem ft vitag La Vi, Quing Ngai nfti rifing, phii ftam khao' nhiiu dgng tfii lifiu khfic nhau mdi cd ftfi cho kit qufi dy dofin tit nhit
dipn tra suit luyin T.4SA.
V A N LI5U
1. Boin VSn Tuyin, Nguyin Nhu Tmng, 1991. Hifin ftyc hda bii toin ftfim dd difin tifin md Mnh hai ehiiu bing phuong phfip tofiu him hgn. TC Ccc khoa hge vi TD. 13/2: 46-51. Ha Ngi
2. Doin VSn Tnyin vi nnk., 2002. Ap dung kJ ftuat hai chifiu ttong phuong phfip difin tto v i phfin eye kich thich dl nfing cao hifiu qui khio s i t thim dft khoing sin. Tuyin tgp BC HNKH ldn Ihti IS Irudng DH M-DC, 67-72. Dgi hgc M- DC HdNgi
3. Loke M.H., 2002. Rapid 2D resistivity and IP taverion using fte least- squares meftod. Res2dinv ver.3.S2
Gcotomo Software, w.-w.w.geoeleclrical.com.
4. Loke M.H, 2002. Rapid 2D resistivity forward modelling using fte finite-difiference and finite-element meftods. Res2dmod ver.3.01 mhloke^ic.jaring. my.
5. Ngnyin Due Qnan, 2005. Ngtofin cuu dng dung phutmg phip do sau difin da cue cii tien dfi dfinh gifi ttifin vgng da flp lfit vung Chu A Thai, A Yun Pa, Gia Lai. Lugn vdn ThS.. Thu vien Dai hoc M- BC. HdNdi.
6. Nguyin Nhur Tnmg vi nnk., 2002, Phuong phap ftim do difin dong mOt chiiu trong mfli ttuftng bit ding nhit ngang. Bii gidng iren dgi hgc vi Dfa vgt ly. Dgi hgc M-BC. Ha Npi.
7. Phgm VSn Thdng, 2010. Bfio cfio Kfit qua danh gia trifin vgng qujng ttiilc va kim logi Mem (Ta, Li, Be) vung La Vi, tinh Quing NgSi. Luu trie LDDC Trung TrtingBp, Quy Nhan.
SUMMARY
Results of geoelecMial Imaging method for interpretation of Un ores and littiium rare metal In La VI area, Quing Ngai Province
Ngtiyin Bic Qugn, Phgm Vdn Thdng, Nguyin Cinh Nho, Tran HOu Trgng Nguyin Vdn Sinh Littiium rarc metal ores ta U Vi area, (Jufing Ngai Provinee have been evaluated ta detail ttuough fte discovery of 40 tin and lifliium ore bodies of mdusttial prospect The resources have been estimated at abom 10,000 tons of LiOj. Lifliium is a valuable rare metal, possible to be used ta many Mgh technology fields. The determtaation of existence of deep-seated ore plays an important role m assesstog fte prospect of deposit Tins article inttoduces fte measurement of electiieal resistivity images effectively applied m fte orientotion of drilltag work, conttibuting to fte confirmation of potentid 01 lithium m Vi^t Nam.
Ngudi biin tdp: Nguyin Tudn Phong
