Hin I'ghi Khou hoc vd Ce'mg nghe} hiai lodn c/iioi. I
GIAI DOAN DONG LUC MOI TRUONG TRAM TICH TREN CO SO ' PHAN BO KICH THUOC HAT CAT
Xtfuven Ngoc Anh', Nguyen Van Vugng', Triin Nghi' ' Vien 1,11 ngii>en vd Mdi Irudng bien,246 Dd Ndng. Ngd Quyen. Hdi Phdiij;
Lniail: [email protected] hoae anh,n2006(5)gmaiFcoin - Frudng Dai bgc Khoa hge 'Fu nhicn. 334 Nguyen Trdi, T'hanh Xudn, Hd Ndi
Su dung cdc miiy linh Irong phdn tich die lieu diu chdt dinh luong dang udiiv cimg phd biin irong nhung ndm gdn ddy bdi chimg cd kha ne'ing phdn lie h n.oi luong ldn dir lieu vd chuyen nhunh cue dir lieu dd thdnh cdc llidng lin cd i^h Bdi bito nity ghi nhdn mdt chuemg Irinh iniiy linh ludn gidi nguon gdc cdc plidn bd kich ibirifc hgt trdm lich dua tren phucmg phitp ciia Riikhin. Chuang 1/ inh cd the xdc dinb cdc i cu Id vdt ly ccr ban citu mdi Iruirng tich lu trdm lich nine .sdng. ddng chdy. hogt ddng ciia gid vu sir luemg tdc gitta chiing viri nhuu Ngodi ra. kit iptu linh lodn lic chuang trinh cimg cd vai trd cpiun trong :i .g CC'IC nghien ciru trdm lich ludn. diic biel Id li-ong khdi phuc cdc mdi trudii:^ licb tu trdm tich Chuong trinh dugc vii't bdng ngdn ngic lap trinh forirein vd ca the chuy tren cdc mdy linh su dung he dieu hdnh Window.
AN IN FLRPRETATION OF DEPOSITIONAL ENVIRONMENT HYDRYNAMICS BASl-D ON THE GRAIN-SIZE DISTRIBUTION OE SANDS
Nuu\en Ngoc Anh'. Nguyen Van Vuong', T r a n Ngi
The u.se of high .speed electronic computers for the analysis of cjuaninative geologiced data has been increasing in recent yeurs because ofthe uhilny uf computers to analyze large cpicintiiies of data and rapidly transform this data into meciningful infcn-mation This paper presents a foriran program foi the genetic interpretation ef the gram size distributions of sands and coarse .sills by using Riikhin's inethocl The program can estimate principid phwiccil environinenlcd fuctors such as currents. Muves. aeolian ucltvily, and i'leir inleructiims In cidchlion. calculated results from the program can be helplul in sediment logiced studies, especially for the reconstruct icm of ancient elepositioned environments The program can run within the Compuc/ I isual Fortran Professional fulition 6.6 0 and Window computers. The foriran .•«•:>' ce codes along with the neces.Mtry input and output data files can be obiu 'icd from the authors s e-mail at anhnndi.imer ac vn or anh n20()6ici),Mmcul com
' Tiei' belli 1^''' N'- 1^"-' clidl vu Diu vdi ly Biin
I. Moi)\r
Nhirng thdnh luu gdn ddy trong nghien euu tram tich ludn da chi ra rdng cdc thdng so ygn triic hai eua irdm lieh hien nay cd the duoc su dung de xac dinh cdc mdi irudng lich lu tjSm tich ed hon [I - 22|. Hdu het cdc nhd nghidn cuu deu cho rang cdc thdng sd kicb thirdc hai trung binb, dd leeh chuan. do bdt ddi ximg va dd nhgn la cdc dau hieu ciia cdc mdi trudng lich tu trdni lieb. Mue dich ciia bdi bao ndy Id gidi thieu mgt chuong trinh foriran ludn giai tu dgng ngudn gdc ciia cdc phdn bd kfch thudc hai irdm tfch dua iren phirong phdp eiia Rukhin 115]. Chuong trinb dugc viet bang ngdn ngir lap trinh Fortran va CO the xae dinh cdc \ eu Id mdi irudng \:ii Iy co ban nbu sdng, dong chay. hoai ddng cua gio va sir luong ldc giiia ehiing \di nbau.
11. FIIUONG PHAP
De ihirc hien nghien ciru ndy. hai quy trinh sau dd)' da dugc thue hicn bao gdm: (1) -xde djnh cdc thdng sd ihdng kd do bat: (2) - xae dinh cdc gid tri kich thudc hat trung binh va do chpn lge Iren so dd "Kich ilitivv hul irung binh - do chem Igc" (hinh 1) do Rukhin [151 de xuat rdi tii dd \dc djuh cdc yeu id \'al ly co ban ciia mdi trudng Ifch lu tram ifch, ddng ihdi ciing xac dmh ca mdi irudng lich lieh lu irdm tich.
Cdc thdng sd thdng kc do hat md td phdn bd kich thudc hat tram tich cd the duoc tinh todn bang cde phuong phdp hinh hgc [5. 8, 20] hoae eac phuang phdp moment [2, 7]. Mdi phuang phap deu cd cdc uu dicm vd nhugc dicm khac nhau. vd vice ehgn lua phuong phdp thi phu thugc vao ban chdt van dc nghidn cuu. Mae dii ed nhicu pbuong phdp khde nhau dd dugc phat Iricn de tinh lodn cac thdng sd dd.
nhung chi ed phuong phap hinh hgc cua Folk and Ward [5] vd phuang phap moment ciia Friedman [7] la dugc su dung rgng rai nhat trong nghien ciiu tram Ifch luan. Tu\ nhicn. vc ban chat, phuang phap moment ehi ja nidt phuang phdp todn hge ehu khdng phai phuang phdp hinh hgc, trong dd mdi hat tram lich deu duge phan dnh thdng qua gid tri ciia cde phep do thdng ke. Vi vdy, phirong phdp niomcnl sc eho kcl qua tfnh lodn cae thdng sd thdng kc do hat chfnh xde ban so vdi phuong phdp hinh hge vd nd cung sc duoc sir dung trong nghien cuu ndy
ITinh 1. Se/ dd "Kich thudv hgt trung binh - Do chon Igc " \ 'lec ludn gicd ce'ic irudng tren scr do du ducrc
chi ra er bung 1
Hdi nghi Khou hoc vd Ceing nghe hicn ludn qiiot Wuj if^-^ y
So dd "Kich ihuc'rc heit tntng binh - Dd chon loc " da dugc dd xuat bdi Rukhin^ 115] ifi hon 40 ndm trudc ddy dd xac dinh cdc eac yeu td vat ly co ban eua mdi trudng tidni ifch, ddng thdi eung xdc djnh mdi trudng Ifch tu tram tfch. Tuy nhicn, cac tfnii todn phirc lap da gdy ra rdt nhidu khd khan khi sir dung so dd Ircn ciia Rukhin. Ngay nay, do cac mdy tinh ed khd nang phan lich mgt lugng ldn du lieu va chuyen nhanh cdc dir lieu dd ihinh cac thdng lin co fcb nen cdc nguyen ly ciia Rukhin da ed the dd dang duge ma hda Ihanh eac Ihudt lodn trong cac ehuang trinh may tinh. Vide ludn giai ede trudng trong so do "Kich thudc hut trung binh - Dii chem loc" da dugc xae dinh trong bdng 1. Cde dudng hien phi tuj'dn trong so do "Kich ihuoc hat irung binh - Dd chgn loc" da dugc xdp xi bang cac phuong trinh khdc nhau vd cung dugc chi ra d bdng 2.
Bung 1. Ludn giui cdc Iruimg tren scr do "Kich thude hat Irung hinh - Dc) chem loc"
Tru'ong W
M C AE U
Cac yeu to moi tru'dng Sdng va ddng ehdy manh
Sdng va dong chay ydu Cde ddng chdy vd hudng Float dgng ciia gid
Mdi tru-ong tich tu t r a m tieh Bd bien (bai bicn, vimg song vd, viing ,>dng vo, cdc viing nude ndng)
Them iuc dia, mat bd thdp, ddi chuyci- ticp va hd
Sdng, bd bicn vd them luc dia Dun edt
Chua duge xdc dinh
Being 2 Xdp xi cdc duong bien phi tuyen Iren sa do "Kich ihirac hat trung binh - loc". Cdc k)> hieu. x luang irng vdi do chon loc, y lirong irng vai kich thuac hat li
Do chgn ung binh Ciic duo-ng bicn phi
tuyen Gl 0 2
03
0 4
0 5
Xap xi cac duong bicn phi tuyen y = -2x + 0 28
y = 3.3333333X- + 0.033333333X + 0.07 y - -5X + 0.9
y = 3x' -I.95X + 0375 y = - 6 x ' +2 05X-0.065
y = -3 2126697X- +27I33484X-0 23486425 y = l 8I06996X- -1 3934156X+ 0 41588477
1 1 1 1 1 1 1 R': FIc so luang quan
£)(,/ /i, Iha chill vd Diu vdt ly Bien
III. CHUONG TRINH MAY TIMI
bao nd\ ghi nhdn mgt chuang trinh mdy tfnh DDE (determination oF depositional Invironmcnisl su dung so do "Kich thudc hat trung binh - Do chgn Igc" eua Rukhin de vie dinh cac \ cu td vdt ly ca bdn cua moi trudng U'eh tu tram lieh va mdi trudng trdm tfch.
Chucme irinh ^u dung eac thdng sd thdng ke kfch thudc hat tram tich nhu duong kinh hat trunp hinh \ L1 JO chgn loc dc xdc dinh eae ydu td vat ly co ban cua mdi trudng tich lii tram tfch. Chuaivj ninh duge viet va bien dich tren ngdn ngir lap trinh Fortran cd the ehay tren cac may tinh -i; Jung he dicu hanh Window. Cdc mdy tfnh su dung cac he dieu hdnh khdc nhu Macinto^li- Linux ed edi ngdn ngir lap trlnh Fortran cung cd the ehay duge chuang irinh ndi ucn ihi^ng qua ma ngudn cua nd. Dinh dang ddu vdo va dau ra cua ehuang trinh diroc thiet kc lat don gian. de hieu ddi vd cd nhirng ngudi il kjnh nghiem su dung mdy tinh Chuan^: ir.,ili ndy cd nhieu uu diem bdi nd chay rat nhanh, de sir dung, eho phep xde dmh cac \eu iv \dl ly co bdn eiia mdi trudng ticb tu tram ifch dong thdi eung gdp phan luan giai mdi nuong lieh lu tram ticb, \ a ddc biel cung rat hiru ich trong nghidn cuu dac di^ni che do ihach - dgng lire eiia cde mdi trudng tram tfch.
Toan ho qin uinh tinh todn ciia chuong trinh may tinh DDE xac dinh cdc yeu td vdt \</
caban ciia mdi irudng Ifeh lu tram tfch va mdi trudng tieh tu tram Ifeh d hinh 2. Liic bat dau mdi chu irinh tfnh todn, ngudi sir dung dugc ydu edu dua ten file ddu vdo va thu muc chua chiing T'dl ed dir lieu dau vdo deu duge chuong trinh kicm tra xem cd dung dinh
^ _ _ _ ^ dang ciia chuong trinh hay khdng, neu cd ldi ( ^ D D E ^ thi chuong trinh se ihdng bao va yeu cdu nhdp Iai chiing. Sau khi dgc xong dil lieu ddu vao da thda man yeu cau ciia ehuang trinh, chuang trinh sc lap tuc tra lai ket qud ngay sau dd tren man hinh MS Dos vd file kel qua kem theo.
Dau vao ciia chuong trinh phai dugc dinh dang theo ASCII TEXT. File dau vao phdi duge tao ra trude khi ehay chuong trinh. Todn bg dii lieu ddu vao can thidt eho chuong trinh tinh loan bao gdm sd mau tram Ifeh, ky hieu mau tram tich va ham lugng phan tram khdi Iugng ciia mdi cap hat tram tich tuang ung vdi mdi mau tram tich. Tdng phan tram eiia eac cap hat phai bdng 100% (±0.2%), ndu khdng chuong trinh se khdng chay va thdng bao Idi.
Ddu ra eiia chuong trinh la mgt file text nam d lhu mue chiia chuang trinh. Cdc thdng tin chinh \ c ket qua gdm ky hicu mdu, gia tri kich thudc hat trung binh va dd chgn Igc, va eae trudng tren so dd "Kich thucrc hgt trung binh - Dd chon loc" ciia Rukhin.
Dgc d* lifiu
_L
dau vao
Xac djnh cac yeu to \'gt ly co ban cua moi tnitme lich tu trani tich va moi iruong tram lich
Hinh 2 - Sa do khdi ciia chirerng trinh im'iy tinh DDE
Hill nghi KhiKi hoc vd Cdng nghC' hii'n lodn i/n.., ;,„, ,/,j^,,
IV. AP DUNG
D6 minli hga chuang trinh may tinh DDE, cac mau tram lich Holocene 6 khu nic viiil, Ticn Yen - Ha C6i (hinh 3) da dugc thu thap dc xac djnh cac yeu to vat ly cn lian cua moi truong tich tu trim tich va moi truang trim tich. Dil lieu phan bo kich thuoc hat tram tlcli khu vuc vinli Ticn Yen - Ha C6i da dugc phan tich bang ca hai phuang phap laj \a pipcl (bang 3). Kit qua luan giai moi truong tram lich cua chuong trinh may tinh DDI. da dirpc chi ra a bang 4
Ban^3' I Idiu hrimiiphdn train cdp hat cua cdc mdu train lich klm virc vinh Tien Yen - Hd Cdi
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Olfi- 0 125 12 26 16 99 21 72 3195
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Being 4 Ket cpid tinh todn tie chucmg trinh DDE
Ky llicu mau
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Kich thu-o'c liat trung binh
ces
0-148 0 116 0 196 0317 0.117 0 852
Do chgn lyc
0 268 0,107 0.041 0 134 0,157 0 077 0.432
Cac t r u o n g tren so tio "Hidi tlttt&c luit trung tiilili - Do clioil
loc" cim Itukhin U W
u
w ^ _ _ _ _
U _ -
u ^ — - u ^__—
Cach ticp cdn ciia Rukhin dugc trinh bay d trdn mang tinh vdt ly bdi nd don gidn hoa cac qud trinh phirc tap, cac yeu td mdi trudng anh hudng den ty Id giu'a cac hat tbo. haJ min ban va khoang khdng gian Id rdng giua cdc hat trdn. Vdi mot do nham dd\ on dinli. be ddy ciia ddng chdy phan tdng dudi tac dgng ciia cac Idp bicn nhieu ddng do sdng va gio '^
tuong ddi nhd so vdi gid iri lucmg ung nhan dugc trong cdc Idp bicn cd ddiu' Jidy dong nhat dang hudng. Trong nhung tinh budng nhu the ndy. ehe dd tron ddu vc ihuy ILTC se nhanh chdng chuyen sang che do rdi nhdm. Khi nhicu ddng rdi cham ldi day se ngan can su tich tu cae hat min vao trong khe hdng eiia trdm lich. Ngugc lai, hoat dgng ciia ddng
fj^ti bau Diu l\, Dtu c bcil vd Diu veil ly Bien
17 //•; cdc mdu Irdm lich dugc lhu thdp a khu vice vinh Tien Yen - Hd Cdi
ehdy manh sc gay ra su phdn tdn phdn tdn tram ticb va gia tang do rdng giQa cac hat tram tram tich. Vi vay, cdc bien ddi nhd nhung cd lien quan den cdc cdp bat trong mgt mau ciing can phdi dugc xdc dmh va ve tren so dd. Ndu nhu cac yeu td dugc de cap d tren tdc dgng ddng thdi eimg mdt luc thi eae phan phdi cap hat thu duoc se bao gdm cde tram tich hat min vdi dd bat ddi xung am vd eac tram lieh hat thd hon vdi dd bat ddi xiing duong.
Do cdch licp can dugc trinh bdy d tren theo quan diem vat ly nen phirong phdp nay ehi cd the dp dung doi vdi trdm tieh cd kieh thude hat tir eat trung ddn cat mjn vd bdt thd Khi cac cap hat ldn hon 0.63 mm cd ham Iugng phdn tram khdi lugng ldn hon 20% Ihi cd the cho kel qua ludn gidi khdng dugc chinh xdc bdi nd chiu dnh hudng ciia eae ehu ky tram tich cd hon Tuy nhicn. trong nhirng trudng hgp nhu vay. cdc dnh hudng dd cd the duoe ghi nhdn va chi dugc loai bd khi dac diem kich thudc hat eiia ngudn eung cap vat lieu tram tich Cling dugc nghien ciru. Thdng qua each dp dung true tiep nay. chung ta cd the ludn giai cdc mdi trirdng tram tich ed tir nhirng du heu phan bd cdp hat tram tich.
V. KET LUAN
Chuong trinh may tinh DDE (the determination of depositional environments) duge viel bang ngdn ngu lap trinh foriran, dua tren so dd "Kich thudc heil trung binh - Do chem Igc" eiia Rukhin, cho phep xde djnh cdc yeu td vdt Iy co ciia mdi trudng tich tu trdm tich va mdi tnrdng tram tich, Chuong trinh sd dung dir lieu ddu vdo la eae gia tri dudng kinh hjit tiung binh. dd ehgn lge ciia mdi mau tram tich. Chuong trinli DDE cho phep tinh toan rat nhanh va kcl qua ciia nd cd y nghTa rat quan trong ddi trong nghien ciiu trdm tich luan, dac bicl la trong khdi phuc eae mdi Irudng tich tu trdm tich.
Ltri cam on
Tap the tde xin cam on su hd trg ciia de tdi nghien cim co bdn ma sd QG'f D 09 08 trong qua trinh thuc hicn bai vict ndy.
//fif iij^hl Kliua Iwc yil Cuii^ njjhe biiiii wan ijiiu, l.ui il,,-^..
TAI U E U TIIAM KIIAO
1. nialt, H., Middlelon. G.. and Murray, R., "Origin of sedimentary rocks". I'l entice - Hall, Englewood Cliffs, New Jersey, 1980, 634p.
2. Chappcll, J., "Recognizing fossil strand lines from grain size analysis". Journal of Sedimentary I'elrology, 1967, vol 37, pp. 157-165.
3. Doeglas. D. J.. "Grain size indices, classincalion and environment", Sedimentology, 1968, No. 10. p. 83-100.
4. Kl-Ella. R. A. and Colleman. J. M.. "Discrimination between dcp(5sitional environments using grain size analyses". Sedimentology, 1985. No. 32. p 743-748.
5. Folk. R L. and Ward, W. C , "Brazos River bar - a study in the significaiUL of grain size parameters". Journal of Sedimentary Petrology, 1957, vol. 27, pp, 3-26 6 Friedman, G, M., "Distinction between dune, beach, and nver sands n,,ni their
textural characteristics". Journal of Sedimentary Petrology, 1961, v. 27, p. 514-529.
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1. 9 Jones. T. A.. "Skewness and Kurtosis as criteria of normality in observed fiequency distributions", Journal of Sedimentary Petrology, 1969, v. 39, No. 4, pp. 1622-1627.
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"Skewness as a paleoenvironmental indicator; discussion and reply". Journal of Sedimentary Petrology, 1978, v. 48, No. 3, pp. 1000-1004.
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11. Krumbcin, C. W., "Size frequency distributions of sediments and the normal phi curve". Journal of Sedimentary Petrology, 1938, vol. 8, No, 3, pp 84-90.
12 Marlins, L. R., "Significance of skewness and kurtosis in enviioiimental interpretation. Journal of Sedimentary Petrology, 1964, pp. 768-700.
13. Marson, C. C. and Folk R. L , "Differentiation of beach, dune, and .Aeolian Hat environments by size analysis, Mustang Island, Texas", Journal of SeJimeiitar)' Petrology, 1958. v. 28. No. 2, pp. 211-226.
14. Rukhin, L. B., "Fundamentals of Lithology: Studies on Sedimentary Rocks'. Nauka, Leningrad, 1969, 703p.
15. Sahu, B, K.," Depositional meehanisms from the size analysis of clastic sediments"' Journal of Sedimentary Petrology, 1964, v. 34, No. 1, pp. 73-83.
'fliu ban Diu ly. Dia cheil vu Diu vdt ly Bien
16. Shepard. V. P. and Young. R., "Distinguishing between beach and dune sands".
Journal of Scdimenlary Petrology, 1961, v. 31. No. 2. pp. 196-214.
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18. Spencer. D. W.. "The interpretation of grain size distribution curves of elastic sediments .lournal of Sedimentary Petrology. 1963, vol. 33, No.l, pp. 180-190.
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1930. 25. pp. 581 - 5 9 9 .
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