Sưu tập mẫu khoáng tướng và atlat khoáng vật quặng trong các mỏ nội sinh Việt Nam

DAI HOC QUOC GIA HA NOI
TRUdNG
DAI HOC KHOA HOC
TUNHIEN
oOo
^'
»
TEN DE TAI
SUtJ
TAP MAU KHOANG
TlTdNG
VA
ATLAT
KHOANG
VAT
ilUANG
TRONG CAC MO NOI SINH VIET NAM
Ma so: QT-05-32
Chii tri
detai:
PdS.
TSKH.
Nguyen
Van Nhan
OAI HOC QUOC GIA HA NOI
RUNG TAM THONG
Tl^^
"HL'
VIEN
Di/sea
II

v«
I
nu
v-
ici
Ha Noi - 2005
BAO CAO TOM TAX
a. Ten de tai:
Suu
tap mau khoang tuong va
Atlat
khoang vat quang trong cac mo n
sinh Viet Nam.
b.
Chu
tri
de tai: PGS. TSKH. Nguyin Van Nhan
c. Cac can bo tham gia:
d. Muc tieu va noi dung nghien
cihi:
- Suu tap mau khoang
tudng
va cac loai hinh quang noi sinh khac nhau d Vi
Nam, xac djnh thanh phan khoang vat va cac dang kien
true,
cau tao quang
- Thanh lap Atlat ve khoang vat quang trong cac loai hinh mo noi sinh d Viet Nan
e.
Cac ket qua dat
ducrc:

- Da suu tap duoc 80 mau khoang tudng bao gom cac
loai
hinh
Ichoang
san khac
nhai
- Da thanh lap mot Atlat ve khoang vat quang thuoc cac kieu quang khac nhau: C
Fe,
Ti, Sn-W, Mo. Cu, Pb-Zn, Au, Sb-Hg
f. Tinh
hinh
kinh phi cua de tai:
0
13.000.000d
0
0
0
13.000.000d
Tu ngan sach Nha nudc
Kinh phi Dai
hpc
Quoc gia
Vay tin dung
Von tu cd
Thu hoi
Tong kinh
phi
thuc chi
XAC NHAN CUA BCN KHOA
CHU TRI DE TAI

icA
l^a^
flVv'
PGS.
TSKH. Nguyen Van Nhan
XAC NHAN CUA
TRUCiNG
1-JU
NHIEN
>
=^^,TS.
JJtit/i'
<y/a/d^
SUMMARY
a. Title of the project: Collecting
mineralography
samples and founding Atlas
metallic minerals in intrusive deposits in Vietnam
b.
Head of the project: Assoc.
Prof.
DSc. Nguyen Van Nhan
c. Participants:
d. Objectives and contents of the project:
- Collecting mineralography samples of different types of intrusive ores
Vietnam, determining mineral composition, structure and texture of ores
- Founding Atlas of metallic minerals in intrusive deposits in Vietnam.
e. Obtained results:
- 80 mineralography samples collected, including different types of miner
resources

- Atlas of metallic minerals of different types of ores founded, including Cr, Fe,
1
Sn-W, Mo, Cu. Pb-Zn, Au, Sb-Hg.
THANH PHAN
KHOANG
VAT VA CAC DANG
KI^N
TRUC CAU
• •
TAO QUANG TRONG CAC
M6
NOI
SINH
VIET
NAM
Cac md khoang va cac diem quang kim loai noi sinh phan bo rong rai khap
la:
tho Viet Nam, nghien cuu chi tiet cd the phan chia ra cac kieu quang vdi nhirng dac die
dac trung ve thanh phan khoang vat, kien tnic va cau tao quang sau day:
I, Nhom cac nguyen to Siderophil: Cr, Ti, Fe
•r
LL Kieu quang Cromit
O Viet Nam quang Cromit chu yeu duoc khai thac
tir
cac md Cd Dinh gan
kli
xam nhap
niii
Nua, khoi xam nhap nay chu yeu la peridotit bi secpentin hoa chua Crom
it hon cd

dunit,
apoharbugit, pyroxenit. Cac bieu hien quang Cromit goc
dupe
biet d
noi:
Niii
Nua va Lang Mun, gan bo khong gian vdi cac khoi xam nhap sieu mafic phan
'
dpc theo dut gay Sdng Ma. Quang thupc hai kieu nguon gdc: magma sdm va magr
mupn. Thdnh phdn chinh cua quang la crompicotit, cromit. Quang co cau tao xam
t£
dai,
thau kinh, 6 vdi kien
trttc
dac trung hat tu hinh, nua tu hinh kich thudc hat tuong
d
deu. Quang Cromit Lang Mun co mat trong cac thau kinh hat
Idn
thupc kieu ngudn g
magma mupn (Anh
1)
L2,
Kieu quang ilmenit-titanomagnetit
Cac mo va bieu hien quang nguyen sinh thupc kieu nay duoc biet d cac vung
>*
Chua (Thai Nguyen), Tam Ky (Quang Nam), Xa Hieu (Kon Tum). Chung cd lien qu
vdi cac xam nhap gabroid. Cac da xam nhap mafic Trias mupn phd bien rpng rai d V
Nam lien quan vdi chiing cd quang hoa titanomagnetit hoac ilmenit.
Thi du dien hinh la mo quang ilmenit Cay Cham (Thai Nguyen) gan bo vdi c
xam nhap gabroid cd thanh phan chii yeu

la
gabro, gabronorit va gabro
olivin,
tro
gabro pegmatit hat
Idn lugng
ilmenit kha giau. Khoang vat quang chu yeu la
ilmer
titanomagnetit kem theo co cac khoang vat sulfur (pyrit, pyrotin, chalcopyrit ). Qua
pho bien dang xam tan vdi kien tnic dac trung hat tu hinh tam. que. kien triic phien m
tach dung djch cung (Anh 2, 3).
Mo ilmenit
Niii
Chiia thupc kieu magma mupn. Ngoai quang Ti. Fe co y
ngi
cong nghiep trong cac thanh tao gabroid con co cac bieu hien khoang Pt, Cu, Ni. Co
/.i.
Kieu quang
magnetit
trong skarn
Anh
1.
Kien
true
hat cromit. Cr Hon Vin. DPD 75x. Nicon (-)
Anh 2.
Hmenit
trong tap hpp titanomanhetit. Ti Cay Cham. DPD
150x.
Nicon (-)

Anh 3. Kien
true
dang phen nua - tach dung dich
ci'mg
Titanmagnetit. Ti Tam Thanh - Tam
Ky. DPD
150x.
Nicon
(-)
Anh 4. Kiln
true
hat nua tu hinh manhetit trong granat. Fe Na Rua. DPD 37x. Nicon (-)
Cac md quang sat ngudn goc skarn co y nghTa cong nghiep
idn
nhat d Viet Nam
dupe
biet d cac vung Cao Bang, Ha
Tinh
bao gom quang magnetit trong skarn Ca (Cao
Bang),
va quang magnetit trong skarn Mg-Ca (Ha
TTnh).
Cac md quang sat skam-Ca Cao Bang thudng hinh thanh d ddi tiep
xiic ciia
cac
xam nhap granit - granophyr tuoi Trias vdi cac da carbonat hoac vdi phun trao axit.
Quang cd dang thau kinh, via phan nhanh hoac dang mach. Thanh phan quang
chii
yeu la
magnetit, doi khi co cac khoang vat sulfur.

Mo quang sat trong Mg-Ca Thach Khe (Ha TTnh) la ddi
tugng
cd y nghTa cong
nghiep
Idn.
Than quang phan bd d ddi tiep
xiic
giiia xam nhap granit vdi da voi (C2-P1)
hoac tiep
xiic
giua tram tich carbonat vdi tram tich luc nguyen Devon va da
simg
(T2.3)-
Than quang cd dang thau
kinh
va dang phan nhanh phuc tap. Thanh phan quang
chu
yeu
la magnetit,
thii
yeu cd hematit va cac sulfur (pyrit, pyrotin, chalcopyrit, sphalerit ). Cau
tao quang thudng gap trong cac md noi tren thudng
la
cau tao khdi dac sit vdi kien
true
hat tuong doi deu (Anh 4, 5).
L4.
Kieu quang magnetit - hematit
Cac md va bieu hien quang nay gap d nhieu noi. Dua vao thanh phan khoang vat
CO the chia ra 2 kieu khoang: magnetit - hematit kieu Trai Cau, thach anh - hematit -

magnetit kieu Lang Khuan.Kieu khoang dau cd lien quan vdi cac da magma mafic (phun
trao va a phun trao) cd nguon goc nhiet dich trao doi, kieu khoang sau thudng gap trong
cac ddi
diit
gay ca nat.
Thanh phan khoang vat chu yeu la magnetit, hematit,
thii
yeu co pyrit, pyrotin,
chancopyrit, sphalerit, galenit. Khoang vat mach bao gom thach anh, canxit, epidot, clorit,
baryt Quang thudng cd
cdu
tao khoi, vi cau tao mach vdi kien triic hat nua tu hinh va
tha hinh (Anh 6).
II.
Nhom nguyen to chalcophil (Cu, Pb-Zn, Au, Sb-Hg, Mo)
2.L
Kieu quang chalcopyrit - magnetit - orthit (trong dd bien chat trao doi).
Hien da biet cac md va diem quang vung Sinh Quyen. Cac than quang thudng tao
thanh ddi keo dai theo phuong Ddng Bac - Tay Nam cd dang thau kinh hoac mach keo
dai.
Quang tap trung trong da bien chat trao doi sam mau (hastingsit biotit). it hon trong
da gneis biotit magmatit hoa va amphibolit.
Anh 5. Kien
true
hat nua tu hinh manhetit dan xen vdi granat. Fe Thach Khe. DPD
75x.
Nicon (-)
Anh 6. Vi cau tao dai manhetit - hematit. Fe Trai Cau. DPD 37x. Nicon (-)
•
Thanh phan khoang vat quang

rSt
phuc tap,
chii
yeu la pyrotin, chalcopyrit, magnetit,
pyrit, menhicovit, orthit,
thii y6u
cd sphalerit, tetraedrit, marcasit, cubannit, arsenopyrit,
hiem gap cd cobantin, lolingit, molybdenit, vang tu sinh, calaverit, crenerit Quang co
cau tao khdi, dai, mach vdi kien
true
hat tu hinh, tam thanh, ca nat, gam mon thay the
(Anh
7,
8,
9, 10).
2.2. Kieu quang pyrotin - pentlandit - chalcopyrit (quang sulfur Cu - Ni trong
dd sieu mafic
-
mafic)
Cac md va bieu hien quang fulfur Cu - Ni dugc biet d nhieu noi: Son La, Tra
Lim,
Dac Sa Mo Cu - Ni Ban Xang (Son La)
la
md co gia tri cdng nghiep dang ke lien quan
vdi khoi dunit
ciing
ten. Khoi xam nhap co dang long chao khdng chan xuyen qua cac
thanh tao da sung xen da phien mica, quarzit va da hoa Devon. Md gdm 3 kieu quang
khac nhau: dang mach (tiem nhap), dang di ly khong deu (dung ly) va kieu quang phong
hoa. Than quang dang mach la loai quang dac sit hinh thanh theo kieu lap day khe

niit
doc
diing nam ngoai khoi xam nhap sieu mafic. Than quang dang xam tan phan bo d day
nham the xam nhap
tira
dang long chao. To hap khoang vat cong sinh dac trung la:
pyrotin, pentlandit, chalcopyrit, magnetit. Dac biet trong thanh phan quang con co nhieu
khoang vat
ciia
Co, Ni, telurua Ag, Au, Bi, Au tu sinh, Pt tu sinh va nhdm Pt, Se nhu
Nikelin, rammensbergit, violarit, maucherit, cobantin, glaucodot, skuterudit, Au tu sinh,
electrum (Au, Ag), calaverit, krenerit,
tellurobismuthit,
sperylit, Pt tu sinh, michenerit.
Quang cd cdu tao khdi, xam tan, mach vdi cac kien
true
hat tu hin
.,
tha hinh, ca
nat, gam mon thay the, dang ngpn lua - tach dung dich ciing (pyrotin - pentlandit). (Anh
11,
12, 13, 14)
2.3.
Kieu quang Cu thach anh - chalcopyrit
Cac md va bieu hien quang kieu nay gap d Van Sai, Quy Hudng, Luong Son, Sudi
Tiat lien quan vdi hoat dpng phun trao mafic. Than quang thudng cd dang mach, lap
d^y
khe
niit
hoac be mat phan

Idp
giua cac da phun trao bi ep phien hoa. Khoang vat chii
yeu la chalcopyrit, khoang vat mach la thach anh. Doi khi trong td hgp khoang vat quang
cdn gap pyrotin, menhicovit, sphalerit, galenit, bismut tu sinh, foseit (telurua Bi), Au tu
sinh, bornit, chancozin, pyrit. Quang co cdu tao mach. xam tan vdi kien tnic thudng gap
hat tha hinh, tach dung dich
cirng
(Anh
15).
Anh 7. Chalcopyrit - cubanit - clorit (dang la ma) xen
giu'a
tap hpp hat manhetit
tir
hinh. Cu
Sinh
Quy^n.
DPD
150x.
Nicon
(-)
Anh 8. Kien
true
dang phen - tach dung dich cung Cubanit
-
chalcopyrit. Cu Sinh Quyen,
DPD
i50x.
Nicon
(-)
Anh 9. Vang dang hat tu hinh trong chalcopyrit. Cu Sinh Quyen. DPD

150x.
Nicon (-)
Anh
10.
Chalcopyrit, pyrotin, clorit xen lap giiia tap hpp hat manhetit. Cu Sinh Quyen. DPD
150x.
Nicon
(-)
Anh
11.
Chalcopyrit xen lap giiia tap hop khoang vat tao da. Cu-Ni Ban Xang. DPD
150x.
Nicon (-)
Anh 12. Pentlandit cung pyrotin xen lap giiia khoang vat tao da. Cu -Ni Ban Xang. DPD
150x.
Nicon
(-)
Anh
13.
Pyrotin, chalcopyrit xen
lap vao
giua khoang vat
tao
da.
Cu-Ni Ban
Xang.
DPD
150x.
Nicon (-)
Anh

14.
Manhetit hat nho tu hinh ciing chalcopyrit xen lap giua khoang vat tao da. Cu-Ni
Ban Xang. DPD
150x.
Nicon (-)
10
Anh
15.
Chalcopyrit ven
ria
bj bien doi mpt phan thanh
chalcozin
xen giua thach anh. Cu Van
Sai.
DPD
75x. Nicon (-)
Anh
16.
Dong
tir
sinh trong da bazan. Ban Mua. DPD
150x.
Nicon (-)
11
2.4. Kieu quang Cu tu sinh
Cac bieu hien quang ddng tu sinh pho bien rpng rai d ddi Sdng Da nhu Ban Mua,
Hudi Long, Nam Mudi, Chieng Ddng (Son La). Dong tu sinh phan tan trong da phun trao
mafic dang hat nhd. Khoang vat mach la thach anh, clorit, zeolit (Anh
16).
2.5. Kieu quang chalcozin - bornit (Cu trong cdt kit)

Cac md va bieu hien quang gap d vung Mau Son, Bac Giang va nhieu noi khac.
Quang hoa phat trien trong cat ket, da phien set vdi mau do, cd khi phan bo giiia cac da
phun trao mafic va axit. Than quang dang thau kinh det, mach, hoac xam tan trong cat ket
hat thd. Thdnh phdn khoang vat chu yeu la chalcozin, bornit, chalcopyrit, tetraedrit, thu
yeu CO sphalerit, galurit, burnonit, arsenopyrit, pyrit, cinabar. Khoang vat mach: thach
anh, nhdm carbonat, baryt. Cdu tao quang thudng pho bien dang xam tan, mach vdi cac
dang kien
true
hat tu hinh, tha hinh dang riem, tach dung djch cung (Anh
17,
18).
2.6. Kieu quang sphalerit - galenit - casiterit gidu Ag
Kieu quang nay bao gdm cac mo va bieu hien quang d Ngan Son, Tong Tinh,
Thugng Am, Ban Ngpc dien hinh la md Ngan Son. Trong vung phat trien cac thanh tao
granit - leucogranit. Than quang co dang mach, o lap day cac dudng
diit
gay hoac phan
bo dpc cac ddi dap vd kien tao, doi noi quang lap vao giua mat phan
Idp ciia
da voi va da
phien vdi. Da vay quanh thudng bi bien ddi nhiet djch: thach anh hoa, greisen hoa, clorit.
Thdnh phdn quang chd yeu la: sphalerit, galenit, arsenopyrit, pyrit, thu yeu la
chalcopyrit, pyrotin, casiterit, stanin, tetraedrit, hiem gap c6 pyrargirit, prustit, calfindit,
stephanit, burnonit va cac khoang vat khac. Quang hoa cd tinh phan ddi, tu tiep
xiic ciia
the xam nhap ra vung da vay quanh cd cac ddi sau:
- Ddi quang sulfur (pyrit, arsenopyrit) chiia casiterit d tiep xuc ngoai xam nhap
granit, hoac trong da phien sericit vay quanh.
- Ddi quang sphalerit - galenit chiia stanin (casiterit) trong da phien sericit va da
vdi.

- Ddi quang galenit
chii
yeu bao gom cac khoang vat
sulfo
mudi trong da voi.
Quang thudng cd
cdu
tao khoi, mach, xam tan, dai vdi kien triic thudng gap hat tu
hinh, tha hinh, ca nat nhii tucmg tach dung dich ciing (sphalerit - chalcopyrit, sphalerit -
stanin) (Anh 19, 20.21,22.23).
12
n^
Anh
17.
Chalcopyrit dang riem xung quanh Bocnit. Cu Bac Giang. DPD
150x.
Nicon (-)
Anh
18.
Vi
cdu
tao riem chalcopyrit - bocnit xung quanh tap hpp hat nho coveniin. Cu Bac
Giang. DPD
I50x.
Nicon (-)
13
w
Anh 19. Stanin tach dung djch ciing trong sphalerit bi ca nat dugc canxit xuyen lap gan ket. Pb
- Zn Ngan San. DPD 75x. Nicon (-)
Anh 20. Mach galenit xuyen cat qua pyrit va sphalerit c6 chua chalocpyrit. Pb

-
Zn Ngan San,
DPD 75x. Nicon (-)
14
Anh
21.
Arsenopyrit va sphalerit co chua chalcopyrit bj ca nat dugc canxit xuyen
idp.
Pb - Zn
Ngan Son. DPD 75x. Nicon (-)
Anh 22. Rutil dang hinh kim phan tan trong da. Pb - Zn Ngan San. DPD
150x.
Nicon (-)
15
Quang thudc kieu ngudn goc nhiet dich nhiet dp cao - trung binh.
2.7.
Kieu quang sphalerit - galenit - pyrit - arsenopyrit
Dien hinh cho kieu quang nay la md da kim Chg
Di6n.
Vung md
nto
trong
t^ng
cau tnic Devon (D| -
D2)
gom da phien set, da vdi phan
Idp
cd bitum. Than quang dang
mach (ddc thoai va ddc diing)
l4p

day
diit
gay, dang
Idp
tiem nhap kieu trao
d6i
thay
th^,
dang tru. Da vay quanh thudng bi
bi6n
ddi nhiet dich dolomit hoa, thach anh hoa, clorit
hoa. Thdnh phdn khoang vat chd yeu la sphalerit, galenit, pyrit, arsenopyrit, magnetit,
tetraedrit, hiem gap pyrargirit, prustit, calfindit, bismut tu sinh, vang tu sinh. Cau tao
quang thudng gap dang khdi, mach, dai vdi cac kien
true
hat tu hinh, tha hinh, gam mdn
thay the, ca nat,
nhO
tuong - tach dung dich cung (sphalerit - chalcopyrit) (Anh 24, 25).
Quang da kim Chg Dien cd nguon goc nhiet djch trao doi nhiet dp trung binh cao.
2.8. Kieu quang sphalerit - galenit trong dd carbonat
Kieu quang nay phd bien rdng rai d phan mien Bac nudc ta: Lang Hit, Con Minh,
Thanh Mpi, Trang Da, Tan Trao, Quan Son, My
Diic
Phan
Idn
quang phat trien trong
cac tang da voi. da vdi dolomit. Than quang cd dang mach, thau kinh. doi khi dang
Idp
trao doi. Thdnh phdn khoang vat rat don gian,

chii
yeu la sphalerit, galenit, cac khoang
vat khac nhu chalcopyrit, pyrit, quang dong xam, burnonit, pyrotin, arsenopyrit c6 so
lupng khdng dang ke. Khoang vat mach c6 thach anh, nhdm carbonat lan baryt. Cdu
tew
quang thudng gap: khdi, xam tan vdi kien triic: hat tha hinh, xen lap (Anh 26).
Quang thudc kieu nguon gdc nhiet dich trung binh thap - thap.
2.9.
Kieu quang galenit - sphalerit
v&i
sulfo muoi Pb vd Sb trong da phun trdo kiem,
Dai dien cho
ki6u
nay
la
cac mo
Tii
Le, vung Na Son. Viing mo Pb-Zn
Tii
Le phat
trien trong cac tudng orthophyr, thach anh, cac da tram tich phun trao, da phien sericit -
clorit cd
tu6i
J-K.
Than quang chu yeu cd dang mach. Khoang vat quang chu yeu la
sphalerit, galenit, thu
y6u
cd pyrit, geocronit, chalcopyrit,
arsenop>Tit,
tetraedrit, pyrotin,

Au tu sinh, semseit, hematit. Khoang vat mach: thach anh, sederit, dolomit, canxit.
cdu tao quang dac trung: ddi keo, dai co nhip. dam ket. khoi. mach vdi cac kien
true
hat tha hinh, xen
l^p,
ca nat. (Anh 27, 28, 29, 30)
Quang
CO
ngudn goc nhiet dich nhiet dp trung binh - thap.
16
Anh 23. Kien triic hat tha hinh pyracgirit giiia galenit. Pb-Zn Ngan Son. DPD
150x.
Nicon (-)
Anh 24. Vi cau tao dai sphalerit - pyrit. Pb - Zn Chg Dien.
17
0A\
HOC
Quoc
GIA
HA NQI
•RUNG
TAM
^HONG
T:!;
'-^U
VEN
p^'/5e_f]
Anh
25.
Tap

hgp
sphalerit bj ca nat dugc canxit
gan
kgt. Pb-Zn Chg
Dign.
DPD 75x. Nicon (-)
Anh 26.
K^t
hgp a
chQ-
c6
sphalerit va galenit. Pb - Zn Lang Hit. DPD 75x. Nicon (-)
18
Anh 27. Sphalerit kien triic hat
6hu
nhau dugc galenit bao quanh giiia tap hgp thach anh. Pb
Zn Tu Le. DPD 75x. Nicon (-)
Anh 28. Cau tao dai sphalerit - galenit - thach anh. Pb - Zn Tu Le. DPD 75x. Nicon (-)
19
Anh 29. Galenit xen lap giua tap hgp hat sphalerit. Pb - Zn Tu Le. DPD 37x. Nicon (-)
Anh 30. Mach galenit xuyen lap giua mach thach anh. Pb - Zn Tu Le. DPD 37x. Nicon (-)
20
2.10. Kieu quang galenit - thach anh
Phan
Idn
cac md va diem quang Pb-Zn d
mi6n
nam nudc ta deu thugc
ki6u
quang

nay, dien hinh la cac md Tien Thuan, nam An Khe, Gia Bac Chiing deu
n^m
trong cac
da granit. Quang cd dang mach. Thdnh phdn khoang vat chu yiu la galenit, sphalerit,
chalcopyrit, pyrit. Khoang vat
hidm
gap la electrum (Au, Ag), telurur Ag. Cdu tao quang
chii
yeu dang mach, khoi vdi cac dang kien true hat tu hinh, ca nat, xen
ISp
(Anh
31,
32).
Quang
CO
ngudn goc nhiet djch nhiet do trung binh.
2.1
L Kieu quang pyrit - sphalerit - galenit - chalcopyrit (conchedan Cu - da kim).
Dai dien cho
ki^u
nay cd cac md
Diic
Bo (Quang Nam) va d ddi Song Da nhu
Lang Cu, Minh Quang, Lung Cua, Lang Chanh. Mdi trudng chua quang la cac da
"phi^n
luc",
phun trao mafic. Khoang vat quang
chu
yiu la sphalerit, galenit, pyrit, chalcopyrit,
thu yeu arsenopyrit, pyrotin, tetraedrit, burnonit, altait (PbTe). Quang thudng co cdu tao

mach, khdi, xam tan vdi cac dang kien
true
hat tu hinh. tha hinh, ca nat, gam mon thay
the.
Kien triic nhu tuong - tach dung dich cung (Anh 33, 34, 35, 36). Quang co nguon goc
nhiet dich - phun trao nhiet do trung binh - thap.
2.12. Kieu quang vdng - thach anh - sulfur
Dai dien cho kieu quang nay la cac md vang Pac Lan, Bdng Mieu va nhieu mo,
diem quang vang d Quang Nam, mien Trung va Tay Nguyen. Than quang la
nhij*ng
mach
thach anh mach nhd, mang mach, dang duoi ngua cat qua da vay quanh thupc cac thanh
tao tram tich luc nguyen, phun trao va bien chat co tuoi khac nhau.
Thdnh phdn quang chu yeu la pyrit, arsenopyrit, sphalerit, galenit, chalcopyrit,
pyrotin, thu yeu co quang ddng xam, rutin, Au tu sinh, electrum, khoang vat mach
chii
yeu la thach anh. Quang cd cac dang cdu tao xam tan, khdi, mach vdi cac dang kien true
pho bien: hat tu hinh, tha hinh, ca nat, gam mdn thay the, xen lap, nhu tuong - tach dung
dich cung (Anh 27, 38, 39, 40, 41, 42, 43, 44, 45, 46).
2.13.
Kieu quang vdng - bismutin - specularit
Thudc kieu quang nay co cac diem quang suoi Tiat (Phu Yen - Son La). Hien -
Song Con, Thang Phudc (Quang Nam) va mot so noi khac. Than quang la
nhung
mach
thach anh sulfur lap day khe
niit
hoac phat trien theo be mat phan phien
ciia
cac da co

thanh
ph4n
thach hpc khac nhau. Thdnh phdn khoang vat gom co p>Tit. arsenopyrit.
21
Anh
31.
Electrum xen giiia galenit trong thach anh Pb-Zn-Au Nam An Khe. DPD
150x.
Nicon (-)
Anh 32. Pyrotin va sphalerit xuyen lap
giu'a
thach anh Pb-Zn - Au Nam An Khe. DPD 75x,
Nicon
(-)
22