VIEN D |A LY VIEN KH&CN VIET NAM HOI DIA LY ''''VIET NAM P H A N TICH DAC DIEM DIA MAO TINH LAO CAI PHUC VU DU BAO HIEN TUONG LU QUET Kieu Qudc Lftp'''' SUMMARY Study characteristics of geomorphology in Lao[.]
VIEN D | A LY - VIEN KH&CN VIET NAM HOI DIA LY 'VIET NAM TICH DAC DIEM DIA MAO TINH LAO CAI PHUC VU DU BAO HIEN TUONG LU QUET PHAN Kieu Qudc Lftp' SUMMARY Study characteristics of geomorphology in Lao Ctd province for flash flood warning For mountainouiis areas of Lao Cai province, severed kinds of natural hazards, such as flash flood, debris, mud flash flood and landslide, present a constant catastrophic rick In order to warn of their appearance we can study geomorphological 'This paper dicusses the necessary and sufficient geomorphologic, lithologic and tectonic conditions for flash flood which should be consider as geologo geomorphological M-arning sings It seems the most vulnerable sites coincide with those areas where exist tectonic shattered belt, rocks which are easy to be crushed and shattered fomiiig weathering products heterogeneous and rich in clay material, availability of thick and abundanl cover of superficial deposits, presence of alluvial fan deposits, etc DAT V A N DE Trong nhfrng nam gan day, ki quel xay cang nhieu va gay nhfrng thid hai Idn ve ngudi va ciia Do nai chju ki thudng la noi phan bd dan cu ddng diic nen thiet hai cang Idn Thai gian qua, Ifi quel da xay d nhieu nai tinh Lao Cai, dac bid la cac huyen nam tren day Hoang Lien Son, nhu huyen Van Ban, Bat Xat, SaPa Lii qud la dang tai bien dac trung va la mgt tai bien nguy hiem ddi vdi mien mii Thuc chat ki qud la mdt trang thai dac bid ciia lii cd lien quan chat che den dac diem dja hinh, dja mao Tren ca sd nhfrng tai lieu dieu tra, khao sat, md ta cac tran Ifi quel d Vid Nam, cluing ta Ihay rang; - Lfi quel thudng xay nhanh, bat ngd, dien thdi gian ngan, nhung sire pha buy lai rat Idn, - Cac Iran ki quel thudng xay vao ban dem va vao dau miia ki, Nhfrng nam gan day, hi quel cd xu hirdng tang len mgt each rd ret, - Noi sinh ki la dau ngudn ciia cac sdng cd ddc Idn Nai chju lii thudng la cira ciia dong chay lain thdi, noi hdi luu ciia mdt vai nhanh sdng Day thudng la noi tap Irung ddng dan cu - Luu vuc xay lfi quel thudng nhd va cd ddc Idn, ddng chay mat cd ddng nang Idn, gay xdi mdn, sup Id phd bien - He thdng ddng chay bj u tac bdi dja hinh hay cac baric tu nhien hoac nhan tao Khi cac vat can bj pha buy tbi ddng hi cang dfr hon Dai hoc Thai Nguyen Hdi nghi Klioa hgc Dia ly Todn qud'c Idn th&S - Hd Ndi, 2010 833 VIEN DIA LY • VIEN KH&CN VIET NAM HOI DIA LY VIET NAM Nlur \ a \ ki quel co lien quan mat thiet den dac diem dja binh dja mao d nai di en chuiu: Niihien ciru dac diem dja mao khu \'ii'c cd the gdp pluin phdng tranh \a gi;.,,, ini thieu thid hai lu qud ga) Trong khudn khd bai bao na\ lac gia xin trinh ba) dac dilin dja mao tinb Lao Cai phuc su du bao bidi lugng ki quel nham giam thieu Ibid hai chung ga\ D.AC DILM DIA MAO TINH LAO CAI Dia mao linh Lao Cai la mgi birc tranh phan anh kha rd nd mdi tuang tac gifra cac qua trinh ngi lire \a ngoai luc sudt Kainozoi tren nen cau tnic dja cluil c6 Nhfrnu nel dac irung co ban cua dia mao Lao Cai cd lien quan vdi lfi quel dugc ihc hien dudi da); 2.1 Binh son van phu hop vdi cau true dja chat cd vol phuong thong trj \h Tay Bac - Dong Nam Neu dem ban d6 dja hinh linh Lao Cai dat chdng len ban dd dja chat, ban d6 kiln tao cluing ta se thay c6 mgt sii triing hgp den ngac nhien gifra dja binh va dudng net cau tiiic dia chat Dudng nlur loan bg cac )cii td cau tnic dja chat Idn deu dugc phai ba)' trdi dja hinh hidi dai Dicu da khang djnh cac qua trinh ndi lire xa)' tren v6 Triii Dal a da) co su boat dgng manh me, chimg thang the va qu)' djnh hudng ciing nhir ciiiing cua qui trinh ngoai sinh \ iec tao dja hinh, liuing king S6ng H6ng phat trien tren mgt ddi dirt gay cimg ten, la ranh gidi phan chia gifra hai midi dja mao va dja chat khac nhau: mien Ddng Bac va mien Tii) Biic Thugc pham vi linh Lao Cai, dja hinh a Ddng Bac thung king Sdng Hdng cd dang Uivdi theo phuong Tay Bac - Ddng Nam, pbii hgp vdi cac can tnic dja chat phat trien trdi cac da tram tich Ui6i Paleozoi Cac lao dja hinh d Tay Bac lai cd dang tuyin theo phuang Ta) Bac - Ddng Nam - phuong th6ng trj ciia cac cau tnic dja chat Ircn cac dii tu6i lir Prolcrozoi den Mesozoi Tai vimg cue Tay Nam ciia tinh, cac day mii ihip co dang lu)en vdi sudn bat ddi xirng dugc phat triln tren cac trim tich luc nguyen tuoi Mesozoi Ciing vdi cac day mii, hinh thai mang sdng sudi khu vuc cfnig cd dang thang, \dng cung lbeo cau tnic dja chat He thong sdng sudi dang loa lia (ly lam) ciing dugc phat trien lai cac khdi xam nhap axil 2.2 Sir phan di >c cao dja hinh phiin anh dac trung ciia hoat dgng tan kicii tao manh me Dja hinh da phan anh kha trung thuc va sinh ddng cac boat dgng tan kien tao Cac he thdng dirt gay phuong Tay BIC - Ddng Nam da boat ddng lich cue Irong Tan kicn tao, keo theo cac chu)'en ddng khdi tang Dang clui y la khoi nang dang dia kl) \di bien Idn da binh da) niii Hoang Lien Son - day mii dd so cd cao Ion nhai Vid Nam Day la day mii cd anh hudng dang kl tdi cac dac trung hau ciia Lao Cai, \a dd ciing lien quan chat che vdi hidi tugng ki kit, lu quel Day mii Con Vol - mgt bg phan ciia phirc nep I6i s6ng Hong cung cd dang mdt day mii dja luy kep gifra hai ddi dirt gay Sdng Hong va Sdng Chay Dong thdi vdi su nang manh dl tao cac day mii cao, dgc ddi dirt gay Song Hong, qua trinh sut kin kien tao tuang doi da dan tdi hinh thung lung vdi tang trim lich KI" •• • X • , o o o ^ ^cogcn, \ai cac be miil them sdng cac bl mai pediment thung king bj phan clt manh lao dja hinh go doi thoai 834 Hdi nghi Klioa hgc Dia ly Todn qud'c lan th&S - Ha Ndi, 2010 VIEN DIA LY - VIEN KH&CN VIET NAM HOI D!A L'r VIET NAM 2.3 Dja hinii Lao Cai cd tinh phiin biic rd riing inli phan bac dia hinh phan anh klui rd diic trirng ciia hoai dgng tan kidi tao vice lao dia hinh da la linh clui ky Cac be mat san bang dugc hmh ihanh d cii6i mdi chu ky tan kiiin lao bidi cdn dugc bao ton kbi rd Iren dja pluin linh Lao Cai, la cac be mill hidi dang phan bd iren cac bac cao 150 - 250ni, 400 - 600m, 900 1200m, 1400 - 1600m, 1800 - 2000m, 2200 - 2400m, va 2800 - 3000m Be mill san bang dien hinh lai Lao Cai la cac be mai cd cao 1400 - 1600m phan bd a Bac Ha vi Sa Pa Dd la cac be mat rgng, bj cac muong xdi va khe su6i pluin cat, tao dja hinh ddi tren luii Ircn cac be mat san bang thudng bao tdn ldp vd phong boa cd be day kha Idn cac khe sudi pluin cat sau vao cac be mat na) tao sudn vach ddc tren tang phong hoa de phat sinh cac khdi trugt, lain gia lang boat ddng ciia cac ddng biin da 2.4 Dia hinh karst d Liio Cai phan anh cac dac trung ciia karst nhiet ddi I bugc pham vi linh Lao Cai cd ba tlianh tao dja chat chira carbonal cd mirc dja Uing khac nhau, hi cac trini lich bien chat tudi Proterozoi thugng - Cainbri thudc he Uing Sa Pa phan bd tai khu vuc day Hoang Lien So'n, tram tich tudi Cambri phan bd tren cac son nguyen Bac Ha - Mirdng Khuong va tram lich thudc he tang Ddng Ciiao liioi Trial phan bd d khu virc Than Uyen Cd sir kluic bid ve dja hinh tren cac tao da gdc khac Cac tram tich carbonal cd ludi co thirdng da bj bien chat, mat cat lai cd sir xen ke dang ke ciia phan kh6ng boa tan, vay mirc karst kem hon Dja binh mii vdi cac dinh dang thap, dang chudng vdi cac sirini thoai vdi ldp dcluvi da) la diic trung cho karst pluil trien tren da luiy Mac dii tren cac Idp sudn tich vdi phan giau Viit lieu set de bj xdi mdn, trugt Id dat, tao dieu kien cho hi bim di, song chinh cac viit lidi khdng boa tan lai giiip cho viec binh cac tang each nirdc, tao lien de cho hinh cac tang nude ngam Cac lao carbonal thudc he Uing Ddng Giao tai Than U)'eii cd mirc ddng nhat cao, chimg bj karst boa numb tao dia hinh niii sdt co sudn vach ddc dirng xen gifra cac tilling king karst rgng Tren be mat lining lung niy cdn phat trien nhieu phdi thu nirdc karst, tao dicu kidi cho viec nuil nude mat tai Than Uyen 2.5 He thong thuy viin da dang dugc djnh hudng kha ro theo cac diit gay vii vimg sut kicn tao Cac dirt gay Idn tao dieu kidi cho qua trinh ngoai sinh tao nen cac thung king song Idn ma dien hinh la thung lung kien lao Sdng Hdng, Sdng Chay Dac diem binh tbai va phat trien ciia cac thung king sdng tren khu vuc la birc tranh the hien rd nhai can Inic dja hinh va tan kien tao khu vuc Sdng Hdng chay lbeo hudng Tay Bac - Ddng Nam la sir khdng che ciia be thdng dirt ga) cimg plurong va sau vi the sdng cd thung king rat hep dang dja hao Tren lanh thd Lao Cai hau nhu khdng cd sdng nhanh vao lir ben trai, cdn ben phai tbi sudi deu ngan Dieu dd ndi len tinh chat tie ciia thung king, lidi quan den tinh tich cue ciia tan kien tao Cac dirt gav cap nhd tbi tao nen cac tluing king cap nho lion Cac dirt gay va khe nirt kiem tao khdng the hidi Ircn dja hinh thi lai ddng vai trd bet sire quan trgng ihanh lao dja hinh bicn dai lien quan ldi cac lai bien thien nhicn dac bid ki tai bidi irugt Id dai va ki quel dang phat trien manh tren lanh thd Lao Cai Hdi ng-hi Khoa hgc Dia ly Todn qud'c la'n th&S - Hd Ndi, 2010 835 VIEN DIA LY - VIEN KH&CN VIET NAM NHUNG DU BAO N H A M GIAM THIEU HOI DIA LY VIETJ