Weathering Sources in the Kaoping River Catchment, Southwestern Taiwan: Insights From Major and
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Transcript of Weathering Sources in the Kaoping River Catchment, Southwestern Taiwan: Insights From Major and
Weathering Sources in the Kaoping River Catchment, Southwestern Taiwan: Insights From Major and
Trace Elements, Sr Isotopes and Rare Earth Elements
C.-F. You, K.-F. Huang, C.-H. Chung and R.-M. Wang
Department of Earth SciencesAlso at Earth Dynamic System Research Center
National Cheng Kung University
Ching et al., 2007 Liu et al., 2007
Outlines
• Sr isotopes
Non-conventional high precision Sr isotopic measurement
• Major and trace elements• REEs
Strontium Isotopes:
84Sr (0.56 %) 86Sr (9.86 %)
87Sr (6.99 %) 88Sr (82.54 %)
87Rb 87Sr+ β -+ anti-neutrino+ energy
(t1/2= 4.88× 1010years)
Geological Applications:
1. Geo-chronometer:
Rb-Sr dating
Seawater curve
2. 87Sr/86Sr Tracer:
a. River water --- weathering process
b. Sediments--- provenance and transportatio
n
c. Biogenic carbonate---seawater evolution
3. Environmental proxy
SST or SSS
Sr Isotopic Composition of Earth Systems
M id -o c e a n rid g eHyd ro h e rm a l c irc u la tio n
Sr/ Sr= 0 .7 0 3 58 7 8 6
D e trita l lo a d in rive rs8 7 8 6Sr/ Sr= 0 .7 1 7 8
D isslo ve d lo a d in rive rs Sr/ Sr= 0 .7 1 1 98 7 8 6
se d im e n t8 7 8 6Sr/ Sr= 0 .7 2 4
o c e a n8 7 8 6Sr/ Sr= 0 .7 0 8
Dissolved load in river 0.7119Detrital load in river 0.7178Sediment 0.724Seawater 0.708Hydrothermal vent 0.7035Oceanic crust 0.702
Geochemical Behaviors of Sr in the “Water World”
1. River water: (a) Reflect the Rb/Sr ratio and “age” of the source rocks;
(b) Sources derived from silicate and carbonate weathering
2. Seawater: (a) Chemically and isotopically “uniform” because of its
long residence time (~2 Ma); (b) Small but considerable regional difference in flux
and ICs occurred on time-scales shorter than the residence time;
(c) Non-conservative mixing in estuaries due to dynamic exchanges
Total mass of Sr in seawater= 1.25×1017 mol
After Basu et al., 2001
Oceanic Sr Budget
1, Steady or not? 2, How Sr ICs change with time?
(Assuming an average seawater concentration of 91.3 M)
Sampling Sites
Reference sites- ST-1 (NEC) and St-C (SCS)
119 120 121 122 123
Longitude (E)
119 120 121 122 123
22
23
24
25
26
Lat
titu
de
(N)
22
23
24
25
26
TAIW AN
S ou th C h in a S ea
KPC
SOT
715-2
South China Sea
Sample Locality
119.5 120.0 120.5 121.0
Longitude (E)
119.5 120.0 120.5 121.0
21.5
22.0
22.5
23.0
Latt
itu
de (
N)
21.5
22.0
22.5
23.0
TAIW AN
South China Sea
121.0 121.5 122.0 122.5 123.0
Longitude (E)
121.0 121.5 122.0 122.5 123.0
24.0
24.5
25.0
25.5
26.0
Lat
itu
de
(N)
24.0
24.5
25.0
25.5
26.0
TAIW AN
1
2
34 5 6
7
April
Aug.
Modern HydrographyTyphoon Toraji
Liang et al., 2003
WRA., 2003
Salinity (psu)
31 32 33 34 35
Tem
pera
ture
(o C
)
0
5
10
15
20
25
30
35
KuroshioSCSSummerWinter
RW
Wang et al., 2002
200-300 m
Kuroshio
NPTW
SCS
100 m
NPIW
PDW
400-600 m
>1300 m
Kao-Ping Canyon Sea Water Masses
RW0
100
Water mass Depth
SCSNPTW
200
SCS400
SCSNPIW
600
NPDW
1300
bottom
High-Precision Sr Isotopic Measurement P- TIMS
0.00E+00
5.00E+07
1.00E+08
1.50E+08
2.00E+08
2.50E+08
3.00E+08
3.50E+08
4.00E+08
4.50E+08
0.0 5.0 10.0 15.0 20.0 25.0
Column-1
Column-2
Column-3
Eluted volume (mL)
Inte
nsi
ty(c
ps)
Sr- Elution Curve
3N HNO3 8N HNO3 3N HNO3 0.05N HNO3
Seawater
ORI 679_S6-10 m
1. 0.709196±032. 0.709197±02
ORI 679_S3-10 m
1. 0.709195±032. 0.709195±02
SB_09-12 (10.5 m)
1. 0.709195±032. 0.709193±02
Recovery> 99.5%
TRITON TI
119.5 120.0 120.5 121.0
Longitude (E)
119.5 120.0 120.5 121.0
21.5
22.0
22.5
23.0L
atti
tud
e (
N)
21.5
22.0
22.5
23.0
TAIW AN
12
16
20
24
28
32
36
40
44
48
52
56
60
64
South China Sea
Δ87Sr (ppm)
The surface distributions of Sr ICs in the KPE
After Typhoon Toraji
1 2 0 1 2 1
2 2
2 3
Aug. 2001
S
31 .5
32 .5
33 .1
33 .3
33 .5
33 .7
33 .9
34 .1
34 .3
34 .5
Other Hydrographic Evidences
(Lin et al., 2003)
1 2 0 1 2 1
2 2
2 3
Aug. 2001
O -18
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
120 121
22
23
Aug. 2002
O -1 8
120 121
22
23
Aug. 2002
S
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
31.00 31.50 32.00 32.50 33.00 33.50 34.00
Δ87Sr= -39.11*S+1338.7r2=0.80
Δ87Sr= -10.82*S+377.08r2=0.70
EM-1
EM-2
EM-3
9.3 ppm(33.99‰)
Salinity (psu)
Δ87
Sr
(pp
m)
Freshening
Surface Seawater Sr ICs vs. Salinity
EM-1: Most radiogenic Sr IC--- (1) intense water-sediment interaction caused by flood plume (2) release radiogenic Sr from silicates due to stronger erosion
EM-2: Normal discharge of the Kao-ping river after heavy rainfalls
2σ
119 120 121 122 123
22
24
26
0.7060
0.7070
0.7080
0.7090
0.7110
0.7120
0.7130
0.7140
0.7150
0.7160
0.7170
121.0 121.5 122.0 122.5 123.0
Longitude (E)
121.0 121.5 122.0 122.5 123.0
24.0
24.5
25.0
25.5
26.0
Lat
itu
de
(N)
24.0
24.5
25.0
25.5
26.0
TAIW AN
Okinawa Trough
20
24
28
32
36
40
44
48
1
2
34 5 6
7
Sr Isotopic Characteristics of the Taiwan River
Δ87Sr (ppm)
Mixing processes of the Water masses--- Evidence from the vertical profiles of the Sr ICs at the SOT
0
100
200
300
400
500
600
700
800
900
1000
1100
0.70915 0.70918 0.70920 0.70923 0.70925
87Sr/86Sr
Dep
th (
m)
ST-1
NEC
0
100
200
300
400
500
600
700
800
900
1000
1100
0.70915 0.70918 0.70920 0.70923 0.70925
87Sr/86Sr
Dep
th (
m)
St-C
SCS
0
100
200
300
400
500
600
700
800
900
1000
1100
0.70915 0.70918 0.70920 0.70923 0.70925
87Sr/86Sr
Dep
th (m
)
NPTW
NPIW
SW
SOT
S1
S6
S3
0.709176 0.709182 0.709176
Seawater Sr ICs is “not” isotopic uniform in the open ocean and marginal sea,but it seems to have a similar pattern in the same region.
0
2
4
6
8
10
0 50 100 150 200 250 300 350 400 450Na (mM)
Ca
(mM
)
st 1-Ca
st 2-Ca
st 3-Ca
st 4-Ca
st 5-Ca0
10
20
30
40
50
60
0 50 100 150 200 250 300 350 400 450Na (mM)
Mg
(m
M)
st 1-Mg
st 2-Mg
st 3-Mg
st 4-Mg
st 5-Mg
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200 250 300 350 400 450Na (mM)
Sr
(μM
)
0
2
4
6
8
10
12
U (n
M)
st 1-Srst 2-Srst 3-Srst 4-Srst 5-Srst 1-Ust 2-Ust 3-Ust 4-Ust 5-U
0
100
200
300
400
500
600
0 50 100 150 200 250 300 350 400 450Na (mM)
B (
μM
)
0
1
2
3
4
5
6
Ba (μ
M)
st 1-Bst 2-Bst 3-Bst 4-Bst 5-Bst 1-Bast 2-Bast 3-Bast 4-Bast 5-Ba
0.7085
0.7090
0.7095
0.7100
0.7105
0.7110
0.7115
0.7120
0.7125
0.7130
0.7135
0.00 0.05 0.10 0.15 0.20 0.25 0.30
1/Sr (μM-1)
87S
r/86
Sr
Surface
Bottom
0.7085
0.7090
0.7095
0.7100
0.7105
0.7110
0.7115
0.7120
0.7125
0.7130
0.7135
0 100 200 300 400 500
Cl (mM)
87S
r/86
Sr
Surface
Bottom
(a) (b)
(c)
Summary
• High precision Sr isotopic measurement can be applied as a new sensitive tracer for studying water mass mixing near estuary
• Rather large variation in 87Sr, >60 ppm, was detected in the Kao-ping estuary and possibly were affected by flood plume, river discharge and surface seawater mass
• Vertical seawater Sr ICs is “not” isotopic uniform in the open ocean and marginal sea
• Dynamic exchange among freshwater, groundwater and seawater are occurring in the Kaoping River estuary and canyon
Summary (continue)
• High dissolved B and Sr in the Kaoping River emphasize the potential impact of mountainous island to the global oceanic chemical budget
• The dissolved REE patterns of the Kaoping River at different tributaries show similar negative Ce anomaly and HREE enrichment
• Strong positive Gd anomaly supports an anthropogenic p
ollution in the river.
• The Sr isotopic variations are rather large, 0.712649~ 0.713592, and show systematically decreasing ratios with distance from the coastal region
THANKS FOR YOUR ATTENTIONEDSRC-NCKU, Taiwan