Tap chi DIA C H A T . loai A. s6 317-318. 3-^010 ^ ^ i f c;
CAC DA NUI LT^A HE TANG TAM DANH d VUNG LANG SON
PHAM DirC LUUNG', D^NG TRAN HUYEN^
' Tong hoi D/a chdt Viet Nam. 6 Phgm A'gfi LSo. Ha N6i ' Viin Khoa hgc Dia dtal va Khoang sdn. Km 9, Thanli Xudn, Hd Npi Tdm tdt: Tir cdc tdi li?u dd thu thdp dugc cd thi di din mot sd nhgn xel sau Cdc dd nui lua hf tdng Tam Danh tgo thdnh mgi ddy phdn df ngdn basalt • andesit gdm chii yeu basalt, andesilobasall, It hem cd andesit; natri trgi ban kah (logt sodic). thudng trung binh kali, thugc logt iholeiit. Chung khd giau nhom ddt hiem nhe: cd hdm lugng cao cua cdc nguyen td Rb. Th. Nb vd hdm lu^ps thdp cua cdc nguyen td Ta, P. Zr, Hf, Ti.
Theo dgc diem dja hoa c<x dd nui lua cua hi tdng ndy khdc biit vdi cdc da basalt cua hi Idng Bdng Giang. Cd thi chung dugc thdnh tgo tir hai ngudn magma khdc nhau
LMdoAu
H? tdng tram tich phun trao mafic Tam Danh lin dau tidn dupe E)oin 88 [4] xic lip d\ra vao thinh phdn th^ch hpe v i da coi quan h? dia chat cua trim tich phun trio - basalt li phu khdng chinh hap true tidp tren thinh tao trdm tich phun trio axit Jura mupn - Creta (he tdng Tam Liuig) vi nhidu tram tich cd hom d khu v\rc L ^ g Son.
Khoi luong eua h? tang bao gdm phdn ldn cic d i phun trio mafic trudc diy dupe quan ni^m li xen k?p trong phun trio Jura d Tam Lung [3] ho$c trong trdm tich nui lira cua di?p Sdng Hidn [2].
Cic da phun u-io cua he tdng Tam Danh phin bd khdng lien luc thanh hai dii theo phuong gdn DB-TN:
1. Dpc qu6c lp IA cii tir gdn deo Sai Ho - Tam Danh ddn N i Qudn.
_ 2. Tir ddo Keo G i - N i U - Ni Chudi den vung Deo Y.
NhOng m?t eit duoc khio sit tdt nhit qua h? tang niy li doan dudng dpc theo quoc lp IA cii lir Tam Danh di N i Qudn
vi doan dudng lidn huydn t^ Bic Ca di Tdng Han theo phuong i vT tuyin ho$c ddng bic.
1. Cic m|t cit Tam Danh - N i Qudn vi Bic Ca - Tdng Han [2]
Trong hai mil cit niy thinh phdn cac d i trong h§ tdng lp ra tir dudi ldn nhu sau:
1. Basalt aphyr, hyalobasalt cd ciu tao vi iS rong, diy 40-60 m.
2. Andesitodacit, andesilobasall miu xim nh^t, xim lyc, diy 5-20 m.
3. Basalt, varioiit xim xanh nh^t vi basalt thuy tinh sang miu, diy 30-60 m.
4. Sdt ket lan tro niu Ida, silic, cit k6t tufijgen, san kdt tufogen miu xim nh?t, diy 10-20 cm ddn 2,5-4 m. Nhi^u noi chiing tao thinh cic thdu kinh mdng giiJa basalt v i phan bd gdn nhu nim ngang song song theo mil ddng chay cua basalt.
5. Basalt Id rdng, hyalobasalt phong hoi dd dang, cd noi cdn ed dang gii cau v i basalt phong hoi thanh ddt dd tuoi, diy 10-30 m.
Cac basalt d?ng cdt hoic lang try siu c?nh gap duoc d vung Thach Loan, Na Lirn, dang varioiit d gin Nimg Cung. Bin Nhing (song Ky Ciing), dang ciu goi vi gii cau gdi d gan Siy Hd, Bic Ca. N i La.
2. Mat cit Khuon Ang - Oeo V - Lang Hang.
M|l cit theo dudng d td tir Khudn Ang qua deo Y den Lang Hang (d phia ddng Ddng Md) do chinh cac tic gii khao sit.
Theo ciu true dia chat ciia vimg niy, trit lu dia ling ciia cae phin vi bao gdm cic he lang cua cac trim tich Trias ha (he tang Lang Son), Trias trung (gdm eic he ting Tam Danh, Khdn Ling vi N i Khudl).
^ ^ ^ H sit dinh deo Y, cac phun trio
^ ^ ^ f f c u a he ling Tam Danh id ra ndm dudi cic d i ryolit cua he ling Khdn Lang.
Cic basalt lp ra vdi bd diy khoang 150- 200 m (F.1809, F.1810). Tiep xiic vdi basalt vd phia dudi li cic thanh tao phun trio axil vi luf ciia chung cua he ling Tam Lung (J3-K ll). Cung trong mil cit niy. 191 vet lp F1814. da quan sit thdy thd til cua basalt trong cac da ryolit ciia he tdng Tam Lung. Di6u niy xic nhin eic di basalt cd hem cac da phun trio cua he tdng Tam Lung. Nhu vay, he tdng basalt Tam Danh d mil cit dang md ti ndm dudi he tdng Khdn Ling (Tia kl). h\ xuyen cit vi bit "til" bdi cic thd i niii Ida Irong h? tdng Tam Lung (J3-K tl). Quan h? niy cdn quan sit duoc d Id trinh Pa Ve - Lang Son (F.1764).
Vdi ly do tren chitng tdi xic dinh tudi cua h? idng Tam Danh la Anisi. Tuy viy, thd basalt niy khdng phin bd rpng rii nhu h?
tang Khdn Ling ma chi cd m^t trong mpt sd mil cdt.
II. DAC OI^M TH^CH HQC VA KHOANG VAT Cic thinh lao ndi lira h? tdng Tam
Danh thude cac tirdng phun nd, phun trio thuc sir v i a nui liia. Thanh phan thach hpc eic d i dupe trinh biy d Bang 1.
1. Cac da thuQC t u - ^ g phun no Tuf basalt mau xim, xim n i a cau tao khdi. Cac manh vun (80-95%) gdm basalt thuy tinh (hyalobasalt), basalt aphyr vi basalt porph\T dang gdc canh. bin gdc canh, bdu due. tuong ddi dang thude (0.5-2,5 mm), ddi khi dat den 6-7 mm. Xi ming (5-20%) li tro bui nui lua hi bidn ddi ihinh chlorit, set, carbonat, quang.
2. Cac 6a thuoc t u ^ g phun trio \h\rc sy 2.1. Basalt aphyr miu xim. xim xanh, hat rat mm, cau tao khdi hoac hanh nhin.
Thinh phan khoing v^t gdm plagioclas (40-65%). pyroxen (5-20%). thuy linh (20-45%). Cic khoang \ai thu sinh la chlorit, actinolil, epidot-zoisil. carbonat.
Trong da ed nhilTig hanh nhan duoc lip day bdi tap hpp silie-chloril-carbonal. Di cd kien tnic inlerserial, hidm khi ed kidn triic viarolit.
2.2. Basalt porphyr miu xim, xim xanh luc, hat min. gdm eic ban tinh plagioclas (1,-3%), pyroxen (< 1%) vi ndn (97-99%) gdm plagioclas (25-72%), pyroxen (3-15%), thuy tinh (15-60%).
Cic khoang vit thu sinh thudng gap la chlorit, epidot-zoisil, earbonat. Cic h ^ nhin dupe lap ddy bdi tip h(;rp khoing vat silic, chlorit, carbonat. Da cd kien triic porphyr vdi nen kidn true inlerserial, hyalopilit, cau tao khdi hoic hanh nhan.
3. Cac d i thupc tu<dng a nui lira Diabas mau xim. xim sim. hat nhd, ciu tao khdi. Thinh phdn khoang vat gdm plagioclas (65-70%), pyroxen (30-35%) vi hat quing nhd miu den. Khoang vat ihu sinh li chlorit. carbonat, epidot-zoisil.
Da cd kien tnic ophit.
TT 1 2 3 4
•i 6 7 8 9 1 2
Bang Sd hieu mlu F.1784 F.176I F.1759 F.1765 F.1772/1 F.I7S6 F.I 789 F.1791 F. 1809/1 F.1810/2 F.1810/5
. Thanh ptiSn khoang vit vs Ten da
Basalt aphyr Basalt aphyr Basalt porphyr Basalt porphyr Basalt porphyr Basalt porphyr Basalt porphyr Basalt porphyr Basalt porphyr Tuf basalt Tuf basalt
hat vun Ban tinh PI.
it it 2-3 1-2 2-3 2-3 1-2 1-2 2-3
Py.
it it
HAT VUN 80-90 90-95
cdc ii h^ ting Tam Danh Nen PI.
40-45 55-65 62-72 50-55 30-35 42-48 25-35 30-35 48-50
Py.
5-10 15-20 10-15 10-15 5-10
3-5 5-10 8-10 5-10
Tt.
43^5 20-25 15-20 30-35 50-55 55-57 55-60 50-60 35-40 "
Ou, _ J L _ -h + + + + + XI MANG
10-20% n-o bill ndi liia bien dSi thanh s^t, chlorit, carbonat, qujng 5-10% ho bui niii lira bifin dfii thanh s^t, chlorit, carbonat, qujng Ghi chu: Pi plagioclas. Py. pyroxen. Tt.
4. Die diim khodng v^t
a Plaffoclas co dang lang try, dang tam (0,06x0,15mm-0,30xl,42mmX dutag ranh gidi thudng thing, doi khi bj gSm m6n, song tinh don gidn. Plagioclas ban tinh phSn bo khdng d6u, co khi la t?p hop ciia 3-4 tinh thfi tao nen kifin tnic tu ban tinh, tk hifim tru6ng hpp thSy kham tren pyroxeii. Plagioclas thu6ng bi bifin d6i mpt phln, d6i khi phSn i6n tinh thfi. Cac dsng Men doi chu yfiu 14 albit hoa, epidot- zoisit hoS, carbonat h o i Theo thanh phjn hod hoc (Bing 2) plagioclas c6 ham ltr(;mg natri cao (Na20 = 10,01-11,56%), ham lirong calci thip (CaO = 0,13-1,40%), ngoii ra c6n chiia mpt luong nho kali (K20 = 0,13-0,70%) v4 sjt (FeO = 0 07- 0,84%), thuOc albit.
b. Pyroxen ban tinh c6 dang tam (0,06- 0,45 mm), bj nut ne v» dpc theo cac khe mit phit hifin chlorit. Kh6ng miu, miu giao thoa vang do b?c hai, CNg = 38-420.
Pyioxen 6 nfin h?t nho, hrong doi ding thinSc (0,030-0,045 mm), bi bifin d6i timg phan ho5c hoin toin thinh chlorit, achnoht. Pyroxen c<S ham Iupng sit cao (FeO " 17,34-17,88%), calci thip (CaO =
thuy tlnh, Qu. quing
14,34-14,62%). Ngoii ra, pyroxen con chiia titan v i mangan. Theo d^c di^m quang hpc v i thanh phan hoa hpc pyroxen gin gui v6i augit.
c. Cic khoing vit phy g|ip hong mlugil i^ la ilmenit, magnetit, zircon, rutin, pyrit''
III.E)i>lCDl£UD|AHdA
Thanh phan hoa hpc cic da nui Ilia hf ting Tam Danh dupe trinh biy ft Bing 3.
Chiing Ii mpt day phin di ngin basalt - andesit vfti him Iupng SiOz dao dpng Irong khoing 46,50-57,70%. Ting him lupng kiem Uung bhih thap hon so vfti phin tid) OTmg bmh cua DeU (1933), natti uu the hon kali (trung btah KiO/NaaO = 0,40) (Htah 2), thuftc loai cao sit (Fe* = 0,61-0,87, trang btah 0,76), cao calci (CAI = 0,36-5,58, hung binh 2,11), Uung btah nhftm (ASI = 0,57- 1,61, dTtng btoh 0,88).
Trfin cic bieu do tuong quan (Na20-l-K20) - Si02, (Na20-l-K20) • (Fe203-l-FeO) - MgO v i K20-Si02 (Hinh ' I, 3, 4) cic di^m bieu diin cic d i eiia M ting roi vio cdc truftng basalt, andcsito- basalt, andesit, hiem hon c6 trachyandesit-basalt vi trachyandesit, (loat tholeiit) trung binh kali.
Ham lupng nhdm nguydn td dit hidm dupe trinh bay d Bing 4. Cic da nui lua ed tdng him luong ddt hidm (SREE) bidn thien trong khoang 183,43-253,58 ppm, trung binh 211,36 ppm. Theo dac didm phan bd ham lupng nhdm nguyen td dit hiem chuin hoa vdi chondrit (Hinh 5) thiy eic d i nui Ida tuong ddi giau nhdm ddt hiem nhe (LREE) so vdi nhdm ddt hidm ning (HREE), dupe thd hien qua ty sd (La/Lu)cn = 3,95-4,83, trung binh 4,30;
(Ce/Yb)cn = 1,86-2,80, trung binh 2,2!.
Dudng bieu didn hoi ddc td trii sang phii, cd di thudng am Eu.
Theo ham luong nhdm nguyen td vdt (Bang 5) v i bieu dd dudng phin bd him lupng chuan hoa vdi basalt sdng nui giOa dai duong kieu binh thudng (N-MORB) (Hinh 6) thay cic da nui [ua cd him lupng cao cua cic nguyen td Rb, Th, Nb so vdi him lirong thdp eua cac nguydn td Ta, Zr, Hf, P, fi v i dit hidm nang (Y, Yb).
^ ^ Bang 2. Thinh phin hda hoc Oxit 1
FSSHffl Mnu MgO CaO',«
•Na:UH
^ K i C ^ Ting
E££i
Ijliil
UKl ' 0,13
99,3C
IP
%tl) plagioclas vd pyroxen cac dd nui lira Ing Tam Danh
1 Plagioclas
» B.444a 1' 65,68 1 21,02 t 0,07
| | o , l 3
^ ^ 1 1 1 . 5 6 1 0,70 1 99,16
B.1597 66,27 20,98 0,60
0,68 10,29 98,79
B.1784 65,76 20,98 0,39
1,4 11,55 100,08
Pyroxen B.I597
51,10 1,17 1,87 17,88 0,37 12,94 14,62
99,35 B.1784
50,51 0,75 1,81 17,34 14,55 14,34
99,30 Ghi chd: Ngudn [4] (Phdn tich bdng phuong phdp microsond).
Him lupng cao cua eic nguydn t6 Rb, Th, Nb vi ty 1? thdp eua NbA' va Ta/Y cd the do svt tuong tic cua magma ngudn vdi v§t chdt vd.
So vdi eic di basalt h$ ting Bing Giang (P3?-Ti bq) (vong Sdng Hidn) cic di basaltoid h§ tang Tam Danh (vdng An Chiu) cd him lupng trung binh Si02, TiOa, (FeiOj+FeO), KzO, (NajO+KjO), m^t so nguydn td vet (Rb, Th, Nb, Ta), cic gii tri (La/Lu)cn. (CeAT3)cn, ehi sd sdt (Fe'), ehi sd bio hda nhdm (ASI) ldn hon, nhung cd ham luong trung binh MgO. CaO, chi so kidm vdi (CAI) nhd han. NhiJng khic bi?t neu tren cd thd do chung dupe sinh thinh tii hai thdi didm khie nhau (P3-T1 vi T2a) vi tu hai ngudn magma khic nhau.
Tit eac tii lieu din ra d tren ed the di den mdt sd nhin xet sau:
1. Cie d i nui lira he tdng Tam Danh tao thinh mot diy phin d\ ngin basalt - andesit gdm ehu ydu basalt, andesilobasall, it hem ed andesit; natri trpi han kali (logt sodic), thudng trung binh kali, thupc loat tholeiit. Chung khi giiu nhdm dat hiem nh?; cd ham luong eao cua cic nguyen to Rb, Th, Nb vi him lupng thip ciia cic nguyen td Ta, P, Zr, Hf, Ti.
2. Theo dac diem dia hda, cae di mii ilia cua hd tang nay khie bi?t vdi cic di basalt cua he ting Bing Giang. Co the chung dupe thanh tao tii hai ngudn magma khic nhau.
49
/ • \
'\ ,' .A^
—! ".
\ ' '
11
\ \^
'\ 1 \
Hmh I. Biiu dd lSa:O^K:0) - SiOiphdn logi vd ggi ten cdc dd phun trdo (theo Le Bas,
1986) cho cdc dd lif long Tam Danh.
Hafi
Hinh 2. Bieu dd Na^O-KO-CaOphdn chia cdc logt magma (iheo Poldervaari vd Green.
l95Hj cho cdc dd h^ tdng Tam Danh.
H.nh 3 Bieu do KO- SiO, phdn chia cc.^ loat magma kiem-vdi fthea W Maure. 1989} cho cai-da V Idng Tam D.mh (LOM-K thdp kali- Mcdnun-K tnmg hinh kali: High-K cao kali) 50
Hinh 4. Bieu dd ATM phdn chia cdc logt magma (theo Irvine vd Baragar. 1971) cho cdc dd h? tdng Tam Danh (TH: logi
Iholeiit; CA: logt kiim-vdi).
HInii 5, Biiu do dtrdngphdn bd hdm hrgng trung hlnh cdc nguyen td ddt hiim chudn hoa vdi chondrit (iheo Haskin. J96S) cho cdc dd
he Icing Tam Danh.
Rb Th Nb
Hinh 6. Biiu do dudng j^dn ho hdm lugng trung binh cdc nguyen to khdng itrang hgp chudn hod vdi basah song nui giiia dgi duang kiiu binh thirdng (N-MORB) (iheo Pearce.
19H3) cho cdc dd h^ tdng Tam Danh
Tam DanH
S i O , T i O , A W .
Fc,a
FeO M n O M g O C « 0 N a K ) K . O P f l . S O . C O , 1 ( , 0 f t j O *
B 4 5 9 a
4 6 . 5 0 2 . 2 2 14.75 8 J 6 5.65 0 . 1 0 3.65 10.40 2 . 7 0 1.45 0.60 0 . 1 0
1.61
^ ^ ^ ^ 3 . 2 7
,^j^^H>ij
• 0 ^
N a , o | n 15
p . 5 4
n i . 7 9 p . 5 8 [ 3 , 0 8 0.41
F 1 8 I 4
5 0 . 1 8 2 J 4 12.96 3 . 7 8 8.9S 0 2 7 S.91 9 . 6 9 [.81
0 . 1 0 0.42 0 8 0
9 7 J g 2 . 0 5
0.13
0.68 0 . 6 1 5.5S 0.24
B 4 5 9
5 1 . 5 0 2 . 1 7 13.65 5 . 7 0 8 10 0 . 0 3 2 . 4 0 8.55 2 . 9 4 0.65 0 , 1 7 0.05
1 9 3
3 . 9 0 101.7 3 . 5 9
0 . 2 2
0.85 0 . 6 4 2 . 8 3 0 . 4 0
F n 8 6 5iJ4
1.62 1 2 . 8 0
9 J 8 0 4 2 3.03 10.07 1.98 0 J 9 0 J 4
0 9 9
9 9 . 1 9 2 . 5 7
0 . 2 9
0.82 0 J 7
B l
5 4 . 2 8 1.01 13.14 4 . 1 2 9 , 6 0 0 2 5 4 2 2 3,93 1,85 , 0 . 9 0 0 , 4 0 0.50
0.91
3.8S 9 S 9 y 2.75
0,45
0 7 6 1.15 4 . 7 3 1.70
O J O 0 J 2 !
2 5 0
5 4 . 4 8 2 , 5 4 11.64 5 2 8 9.70 O J O 2 2 5 5,81 1.87 1.42 0.18
2 . 6 4
0.64 I . I O 3 2 0 9 9 . 0 7 3 2 9
0.75
0,17 0.77 2 2 8 0 2 9 ]
F 1 7 S 7
5 4 . 5 6 1,90 1 3 j 3 7 2 6 S.08 0.42 4 2 4 4 J 6 2.42 0.74 0.05
0.60
-
9 8 2 6 3.16
0 2 0
0.77 1.06 1.69 0 2 4
F 1 8 0 9 / 1 5 4 . 7 6
2 . 9 7 i l 83 2 ; 9 9 1 1 2 6 0 2 5 2.01 7.19 1.99 1.14 0 2 9 0.08 0 2 3
--
9 7 . 1 9 3.13
0.57
0.87 0.67 2 . 9 0 0 2 7
B 4 4 4
5 4 . 9 8 i , 4 7 13„^7 1 2 0 8.82
6.17 3 . 1 2
2 . 0 2 0 2 7
0 . 7 6
2 . 6 5 100.4 7 2 4
0 2 9
0.61 0 . 8 3 0 J 2 0.78
F ( 7 5 9
5 5 , 7 6 1.74 13.69 3.85 10,80 0.42 3 . 0 0 4 . 0 1 3 2 6 0.48 0 2 s
0 . 4 4
—
9 8 . 0 6 4 . 0 4
0.13
0.83 1.00 1.14 0 . 4 6
TOU
5 6 . 1 8 2 . 1 6 11.62 3 . 0 7 11.16 0 . 5 0 3 2 5 5 2 0 2 2 7 2 . 1 6 0 2 2
0,95
0 2 0 0.46 1 2 0 9 9 . 0 9 4 . 4 3
0.95
O S I 0 75 1 5 7 0 2 1
B 4 4 4 4 k | ^ |
5 7 2 8 1.88 16.10 4 . 4 5 4 . 0 2 0 . 1 0 1.98 3.S8 4 2 1 1.55 0 2 1 0.02
1.44
3.65 1 0 1 2 6 2 6
0 2 3
0 . 8 1 1.03 0,85 0 2 1
5 7 , 5 6
1 1 4 5 1 4 3 i l . 9 2 0 . 0 1 5 . 9 9 1.75 3.86 0.90
0 2 5
1.96 9 9 . 4 0 4 . 7 6
0 2 3
0 , 6 7 1.08 0,44
| B P 6 O |
5 7 . 7 0 2 . 4 7 11.22 2 . 1 2 1 1 2 6 0,02 7.77 1.02 2 2 5 0,95
- -
0,42
2 , 6 7 100.1 3 2 0
0.40
0.63 1.61 0 2 6 0.63 0.45
Ghi chu: 1.3.5.9.12.13.14- Ngudn f4J: 6.11: Ngudn f5J: 2.4.7.8.10: Ngudn [IJ Bang 4. H i m (u^ng (ppm) nhom nguyen td dit hidm trong cic da nui lira
he tang Tam Danh rr
1 2
) )
7 1 9
I I 13
S6h.eu
f-17S9 F I 7 6 I F 1763 1- 1765 F I 7 T 2 I F I 7 U F 171}
F I 7 U F I 7 S J F I7OT F1790 F 1791 f MSOf-1
U 33.0t 31.97 31,11 32.1>
13.97 } 3 , M 30.44 3 I J 0
nm
3 1 7 3 3J,7»
J0.9T 13.00
Ce 60 TD 6 S 5 I 64.73 59,79 56.00 t V "
J0.S3 S1J9 54.45 } | , 7 7 }:.S5 41,4S 70 JO
Pr
• « . l 2.44
<0.l 3,49
<0.1
<0.l
• 4 3 . 1
<0.1
* 0 . l
9 : 1
» d 37„«) 3 f l . K 30,20 2 1 4 1 34.99 25,69 11.02 20.41 23.13 3X33 2 ' ' 8 0 20.15
Sm 5.1B 7 2 2 S.«9 5.45 6.4}
4.61 3,20 1.16 3.97 3.51 4.46
1.17 Fu 1.65
1,19
1 11
1.46 1 55 1 5 1 I J 4 1 (•:
2.19 C d
-!,'>
9 2 6 6,90
1,30 6 J S 4 2 4 4 . 4 ; i . l 6
t l , 4 2 H I
' 0 . 1 I.DO - r t l l
0.77
«0.) ' 0 , 1
<0.l ' O . I
- 0 1 0.39
I3y 9.41 9 J 2 1.67
1 2 7 9, [3 R.I4
».2T
•>J0
1.6}
1.12 9.99
Ho t , l 6
l o t
1.65 0 74 a j 2 0.44 0 5 7 0.39 0 6?
0 4 1 2.15 B 4 J 7
3 1 6 3 1 ' 4.96 3.93 2S4 2 J 6 3.51 2.13 3 2 9 2,45 7 2 5
T B
0,43 0 76 D.40
0 2 *
0.09
<0.1
< 0 , l 0.01 0.02 0.05 0 . 1 1 0 3
Yb 6 2 7 6 t l 5,99
6 J 6 i.70 5,94 6 2 5 5 75
La o.as 0.15 0.7S
on
0,79 0 70 0 6 9 OM 0,73 o i l 0.66 5 6 4 j o n
Y 57,13 56 95 5 6 J 9 56 J J 46.19
57,03 63.52 5 9 X 66,66 5 9 J « 47.67
( U - L u k n 4,00 3.99 4 2 7
4.11 4 2 9 4,41 4 70 4.13 4.49 4,16 4 J 3 1.9S
(CeYbfcn 2 2 0 2 2 t 2,45 2.19 2,64 2 2 0 2JB2
1.97 2JU IM 2fa IM
Ghi chu: 1-13: Nguon (IJ. Ca quan phdn lich: Trung tdm PTTN Dia chal. Phuong phdp phdn lich: Plasma-TCX 01 - UUCP 9"
Bang 6. Him lip^mg (Ppm) nhom nguySn 16 v4t trong cac 6i nui lira h# ting Tam Danh
TT 1 7 1 4
« ^
7 8 9 10 II
Sohigu mlu F.I759 F.I786 F.1785 F.1765 F.1772 F.I763 F.1772/1 F.1785 F.1789 F.I791 F. 1809/1
Sr
557 578
865 523 600 601 580
K 3984 4897 6142
9463 Rb 317 141 128 176 140 182 175 138 114 128 68,7
Ba 223 178 481 312 205 340 156 189 475 177 576
Th 10,20 14,70 13,80 11,80 14.30 2 2 3 14,70 13,90 11,80 12.30 11,90
Ta 1,14 0,89 0,69 1,71 1,95 0.32 0,96 0,82 0,52 0.70 0,59
Nb 31,40 76,8U 80,00 34,10 26,00 88,70 78,60 77.20 79,30 81,20 73,80
Ce 41,00 /0,I0 67,60 72,00 43,00 52,10 89,20 78,50 71,40 73,70 75,50
P 1223 1485 219 655 698
1266 Zr
20U 213
203 189 211 222 217 452
Hf V,90 7,60 8,42 12,1 8,08 6,55 5.79 7,95 6,72 4,69 7,50
Sm 6.53 4,21 3,65 7,62 7.55 4,03 3,14 4.12 3,35 4,63 10.50
Ti 10431 9711 11390
1798 1 21,50 66,70 62.00 21.00 20,40 20.10 64.70 54,30 66,40 65,00 21,80
Yb 2J1 6,« 5.91 l.»
lu
2,19 6,S1 5,52 6,11 6,50 2,17 Ghi chu: l-ll: Nguon [IJ. Ca quan phin lich: Viin Hgt nhan Di Lgt.
Phuong phip phin tich- Kich hogl neutron, huynh quang lia X 3. Trong Irung An Chau, ngoai cac da nui
10a mafic con c6 cac da nui lua felsic Chiing CO lien quan chst che voi nhau trong khong gian v^ th6i gian thanh t^o, tao n€n loat magma tirong p h ^ kha di6n hlnh.
4. Boi c5nh dia d6ng lire sinh thfinh cic a basalt c6n nhieu y ki^n kli^c nhau: rift nOi l\ic (Nguyin Xuin Tung. Trin Vin Tri I992);y.h qui cua nhimg t?o vom diapir (Nguyen Kinh Quic vi nnk, 1992); cic qui trinh phd hiiy ria craton Nam Tning Hoa xdy ra duoi anh huong cua plum manti ki^u Emeishan (Trin Trgng Hia, 2005, 200Tj.
Day Id vin d€ cdn ti6p tue nghidn ciiu.
VANU$U
Bdc B6. Luu trir Dia chit. Hi Ngi 1. Doin Kj- Thuy (Chi biin), 2001.
Dja chat va khoang sdn to L ^ g Son (ty i?
1/200.000). Luu trir Dia chil. Hi Ngi 3. Dovjikov A.E, (Chu biin), 1971.
Dja chdt midn Bdc Vi^t Nam (BSn djch). Nxb KHKT Hi Ngi:
4. N ^ y l n Kinh Qu6c (Chi biin), 1991.
Dia chdt va khoang sdn nhom t6r Binh Gia (Lang Son) ty IS 1/50.000. Luu tri Die chit. HiNii
5. Nguyen Tri Vdt (Chu bien), 1997.
Dia chil va khoing sin nhim ti Hihi Lung (Lang Son) ty 1? 1/50.000. Luu tri Dia chit. Ha Ngi.
1. DSng Tran Huyen (Chi biin), 2006. Cdc trdm tich Phanerozoi o Dong
SUUIUARY
Volcanic rocks ofthe Tam Danh Fonnation in L^ng S o n Phgm Due Luang. Ding Trin HuySn Volcanic rocks of the Tam Danh Formation form a short differentiated series of basah-andesite, which consist mainly of basah and andesitobasalt, and lesser, andesite.
In chemical content, sodium is richer than kalium (sodic series) with usually medium
? ° " ' ' " ' °f r"'"™' ^^ *<=y Wong to the tholeiitic series. They are quite rich in the LKhh and have high content of Rb, Th, Nb and low content of Ta, P, Zr, Hf, Ti.
Accoramg to geochemical characteristics, they differ from basalts ofthe Bdng Giang Formation that could be derived from two different magma sources.
Nguii biin tip: PGS.TS Bui Minh Tim
52