Journal of Geophysical Research-Earth Surface
Supporting Information for
“A test of the cosmogenic 10Be(meteoric)/9Be proxy for simultaneously determining
basin-wide erosion rates, denudation rates, and the degree of weathering in the
Amazon basin”
”
H. Wittmann1*, F. von Blanckenburg1,2 N. Dannhaus1, J. Bouchez1,3, J. Gaillardet3, J.L. Guyot4,
L. Maurice5, H. Roig6, N. Filizola7, M. Christl8
1
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam,
Germany
2
Also at Institute of Geological Sciences, Freie Universität Berlin, Germany
3
now at Institut de Physique du Globe de Paris- Université Paris Diderot, CNRS, Paris Cedex 05,
France
4
Instituto de Pesquisa para o Desenvolvimento (IRD), Casilla 18-1209, Lima, Peru
5
Université de Toulouse, UPS (SVT-OMP), LMTG, 14 Av. E. Belin, Toulouse, France, and IRDLMTG, 14 Av. E. Belin, Toulouse, France
6
Institute of Geosciences, University of Brasilia, Brasilia, Brazil
7
The Federal University of Amazonas, Av. Darcy Vargas, Manaus, Brazil
8
Laboratory of Ion Beam Physics, ETH Zurich, HPK H25, Zurich, Switzerland
*Corresponding author. E-mail address: wittmann@gfz-potsdam.de
Contents of this file
Text S1 to S6
Figures S1 to S4-2
Tables S1 to S4
Introduction
This supporting information file contains 7 sections.
Section 1 contains detailed information about the study area and the sampling scheme (Text
S1).
1
Section 2 contains information about the analytical methods applied in this study, described in
Text S2. Figure S1 is a schematic illustration of water sample treatment and Figure S2 shows
the results, i.e. the obtained Be concentrations, of this water treatment.
Section 3 contains information on a Be yield test carried out during ferric hydroxide
precipitation, including Table S1 and Text S3 that explains the conducted experiments.
Section 4 contains Table S2 that supplements qualitative information on the mineralogy of
suspended sediment samples from depth profiles, obtained from XRD measurements.
Section 5 contains information on the chemistry of the reactive phase, with explanatory Text
S4 and Figure S3, expressed as a ratio of [Element X]reac to [Element X]total for major cations and
Be. The data to construct this figure is contained in Tables S3-1 (bedload data) and S3-2 (data
from suspended sediment depth profiles).
Section 6 contains information on retentivity, with explanatory Text S5 and two figures. Figure
S4-1 shows the correction of measured Kd values carried out in accordance with a published
experimental dataset [You et al., 1989], and Figure S4-2 compares meteoric-derived
denudation rates derived from two approaches, one is based on an equation ignoring a
correction for retentivity, and one is based on an equation including the retentivity correction.
These two approached agree well, i.e. we observe no retentivity issues.
Section 7 reports the depositional flux, erosion rates, denudation rates, and weathering
degrees calculated from published data Orinoco data [Brown et al., 1992] with an explanatory
Text S6 and Table S4.
Section 1- Detailed sampling information
Text S1:
a) bedload samples
The terminology for samples as well as bedload sampling material are identical to those used in
Wittmann et al. [2009] for Beni, Madre de Dios, Orthón, Mamoré, upper Madeira, and Grande
samples. For other samples, we used the terminology and sampling material of Wittmann et al.
[2011a]. Both studies used coarser sandy sediment for in situ-produced cosmogenic 10Be
analysis, whereas this study uses mainly the 30-40 μm grain size fraction sieved from bedload.
In addition to new bedload data, we use here averaged data from all grain size fractions (from
<30 to 250 μm for samples Be 1, Cb 2, Br 7, and Obi) resulting in e.g. “Be1avg”, and the 30-40 μm
fraction of samples Be 2 and Gr 19, all from Wittmann et al. [2012].
Samples characterizing the Andean geomorphic regime are bedload from the Solimões River
(samples Pe 101,107, Peruvian and Ecuadorian Andes), and the Madeira River (samples Mad
19,20, Bolivian Andes), and its main tributaries Beni, Orthón, and Madre de Dios (samples Be 117, Or 16, and Md 15, respectively) as well as the Mamoré-Grande (samples Mar 18 and Gr 19,
representing the lower and upper basin, respectively). To characterize the cratonic Shield
regime, we sampled the Guaporé River (Cb 2: southern Brazilian Shield), the Aripuana (Cb 3:
central Brazilian Shield), and the Teles Pires (samples Cb 5,6: northern Brazilian Shield). The
2
Guyana Shield located north of the central lowlands is drained by the Branco (samples Br 2 to
7), which is the main tributary of the Negro River (Ne 0.6). The Negro joins the Solimões at the
city of Manaus, forming the Amazon River. Upstream of this confluence, we sampled the lower
Solimõés at Manacapuru (sample Man 2.4) and downstream of the confluence, we sampled at
Iracema (Ir 1.75). Between Iracema and Parintins (samples Par 0.9 to 2.2), the Amazon River is
joined by the Madeira River (samples Mad 0.3 to 1.7). The lower Amazon was sampled at
Óbidos (Obi).
b) suspended sediment depth profiles
Suspended sediment samples collected along depth profiles (termed “DSS”; see Table 3 for
sampling depths) from the Andean zone have been analyzed for the Beni (Be-DSS, see Table 3
in main text), and for the Madre de Dios (Md-DSS). In the central Amazon lowlands, DSS
samples were collected from the Madeira close to its confluence down to a maximum depth of
12 m, and from the main Amazon River at Óbidos down to a maximum depth of 55 m. These
samples were collected in 2006 during the cruise when bedload and water samples (see below)
also were collected.
c) water samples
Andean water samples have been collected in 2001 for the Beni (Be1-W) and the Madre de Dios
(Md15-W). Central Amazon rivers were sampled for water in 2006 (when sampling for bedload
and DSS samples was also conducted) at Iracema (Ir-W), Óbidos (Obi-W) and Madeira (Mad-W1
and W2) close to the confluence with the Amazon River. The Negro water sample was collected
upstream of the Negro-Amazon confluence near Paricatuba. At Manacapuru on the lower
Solimõés, we used data from a water sample from Brown et al. [1992].
Section S2: Analytical methods
Text S2:
a) bedload samples
Samples were weighed (see Table 2 in main text), and the leaching procedure of Wittmann et al.
[2012] was applied under clean lab conditions (see Wittmann et al. [2012] for full procedure).
Wittmann et al. [2012] found that most [10Be]reac is located in the fractions of amorphous and
crystalline oxides. These so-called am-ox and x-ox steps were combined to a “reactive” fraction
for most samples before measurement. All leached fractions and, after dissolution, the silicate
residual (containing [10Be]min and [9Be]min) were taken up in 3M HNO3. From these solutions
(“OES split”), aliquots were taken for stable 9Be and other elemental analysis (section S5 for
chemical characterization of extracted and residual phases), and the remaining solutions (“AMS
split”) were spiked after splitting using ca. 200×10-6 g/g of our in-house “Phenakite” 9Be carrier.
Spiked solutions were left to equilibrate for several hours, dried down again and taken up for
column separation. The separation of 10Be was carried out according to the simplified
separation scheme of von Blanckenburg et al. [1996; 2004] including anion- and cation column
separation and alkaline precipitation. 10Be/9Be ratios were then measured at the ETH Zuerich
accelerator mass spectrometer (AMS) [Kubik and Christl, 2010]. Blanks (mainly from carrier)
yielded an average 10Be/9Be ratio of 2.51 ± 1.2×10-15 (n=11)). Blank amounts were subtracted and
the standard deviation of their mean was propagated into all [10Be]. The calculated [10Be],
3
which were corrected for 10Be portioned to OES splits, are given in Table 2 in the main text with
combined analytical and blank uncertainties. 9Be and major elements were measured using the
OES split of the 3M HNO3 solutions by ICP-OES (Varian 720-ES, axial optics). We processed a
second sample batch with newly weighed samples and measured [9Be]reac again to check the
consistency of the procedure. Results of both batches are given in Table 2 in the main text,
showing agreement mostly within uncertainty. In addition, we checked the accuracy of [9Be] by
routinely measuring reference materials with similar matrix, comprising the granite “GA”
(CRPG, published Be concentration is 3.6 ± 0.35×10-6 g/g Be (1σ std. dev.; Govindaraju [1995])
and the rhyolite “RGM-1” (USGS, published Be concentration is 2.4 ± 0.2 ×10-6 g/g Be (1σ std.
dev.; Govindaraju [1994]). These reference materials were powdered, weighed, dissolved and
diluted to a concentration of ca. 50 and 30×10-9 g/gsolid Be for the GA and the RGM-1,
respectively, matching Be concentrations of samples in measurement conditions. We obtained
3.06 ± 0.21×10-6 g/g for the GA, and 2.16 ± 0.15×10-6 g/gsolid for the RGM-1 as mean long-term Be
concentrations (n > 10 over a period of 2 years). Uncertainties given are the 1σ standard
deviation calculated by propagating uncertainties from initial sample weight (5%), long-term
OES repeatability (5%), and 1% balance uncertainty. Despite a systematic underestimation of
Be concentrations by about 15%, results are very similar to the suggested range of the
published values.
b) suspended sediment samples from depth profiles (“DSS”)
The same workflow as for bedload samples was applied to suspended sediment samples from
depth profiles. These samples were treated in the new ultra-clean HELGES (Helmholtz Lab for
the Geochemistry of the Earth´s Surface) facility at GFZ Potsdam and extracted am-ox and x-ox
phases were measured separately (Table 3 in the main text). Measurements of OES splits
involved the same method as for bedload samples (on the same instrument) and yielded similar
long-term accuracy. AMS splits were treated like the bedload samples as described above.
10
Be/9Be ratios were measured at the Cologne University AMS [Dewald et al., 2013]. Blanks
yielded an average 10Be/9Be ratio of only 6.3 ± 3.8×10-16 (n=4), whose amounts were subtracted
and uncertainties propagated. In addition, we performed qualitative XRD measurements for
bulk suspended sediments of the Madeira and Óbidos depth profiles (Table S2).
c) water samples
Water samples were separated into 2 aliquots, where one subsample was used for sector-field
HR-ICP-MS (Thermo Scientific Element 2TM) 9Be analysis and another was used for 10Be analysis
on an AMS (Fig. S1 and Table 4 in the main text). The AMS samples were weighed, spiked
(blanks yielded an average 10Be/9Be ratio of 1.75 ± 0.07×10-15, n=2) and a FeCl3 solution was
added to co-precipitate Be with ferric hydroxide (an approach we adapted from Jeandel [1993]
and Frank et al. [2009] developed for ocean water). After centrifugation, the precipitate was redissolved and treated by anion and cation ion chromatography. Be yields were checked by
running test solutions containing known Be concentrations; for all test runs resembling river
water (Text S3), Be yields were higher than 90%, which we regarded as sufficient. The ICP-MS
splits were pre-concentrated and taken up in 0.3 M HNO3 (Fig. S1), spiked with Indium solution
as an internal reference using matrix-matched standards. We checked the accuracy of ICP-MS
analyses by measuring the natural water reference material SRM 1640a (NIST, USA), certified
value is 3.002 ± 0.068×10-12 g/g Be (1σ std. dev.). Over the course of 3 years, we measured a
mean value of 3.12 ± 0.24×10-12 g/g Be (1σ std. dev.), yielding Be concentrations in good
agreement with certified values.
4
Fig. S1: Schematic illustration of water sample treatment. Method for AMS splits involving coprecipitation by ferric hydroxide was adapted from Jeandel [1993] and Frank et al. [2009].
5
Fig. S2: 10Be (at/gwater) and 9Be (×10-12 g/g) results of the water (“diss”) measurements. [10Be]diss
of Amazon basin water samples are given by black circles (left axis) and [9Be]diss are given by
white squares (right axis). The label “B” indicates data by Brown et al. [1992] in Amazon Rivers.
Section S3: Be yield test
Text S3:
We have conducted tests of the precipitation method that are based on the methods developed
by Jeandel [1993] originally developed for Nd isotope measurements in ocean water and the
method developed by Frank et al. [2009] developed for meteoric 10Be measurements in ocean
water. Based upon these tests, we determined that adding 1 mg Be to the 100 mL sample
solution produced near-complete recovery of Be, and prepared samples accordingly. Be yields
were consistently high, being on average 90% (Table S1). However, when adding organic matrix
to test solutions (amount resembling a dissolved organic carbon concentration of 20 mg/L),
recoveries were consistently lower, being ca. 60%. These yields are still sufficient for the
determination of 10Be/9Be ratios (after spiking with 9Be); absolute 9Be concentrations are
determined from direct Be measurements following pre-concentration by evaporation.
Table S1- Result of precipitation tests using ferric hydroxide
Matrix of solution
Solution 1
Solution 2
Solution 3
Solution 4
Solution 5
(Elements in mL/L or ‰)
No matrix added
No matrix added
Ca: 3; Mg: 5; Na: 2; Si: 10
Ca: 3; Mg: 5; Na: 2; Si: 10
Ca: 3; Mg: 5; Na: 2; Si: 5
pH
~10
~9
9
9
8-9
FeCl 3 *6H 2 O Oxalic Acid
(mg/L)
83
200
75
25
12.5
(mmol)
-
a
Be added
-6
b
(× 10 g)
94.1 ± 0.9
189.8 ± 1.9
195.1 ± 2.0
197.2 ± 2.0
214.8 ± 2.1
Be in supernate
(× 10
88.8
170.5
174.6
184.8
195.4
-6
±
±
±
±
±
c
Be yield
g)
Be on filter
(%)
94.4
89.8
89.5
93.7
91.0
4.4
8.5
8.7
9.2
9.8
d
-6
(× 10 g)
2.6
3.2
7.8
19.7
39.7
e
Average yield (no organic matrix) 91.7 ± 2.3 %
Solution 6 Ca: 3; Mg: 7; Na: 2; Si: 5; K: 0.5
9
48
400
± 12 361.9
± 18.1
90.5
Solution 7 Ca: 3; Mg: <7; Na: 2; Si: 5; K: 0.5
9
48
0.80
400
± 12 238.3
± 11.9
59.6
Solution 8
No matrix added
9
48
0.84
400
± 12 245.2
± 12.3
61.3
Note that all solutions were equilibrated >1 day after pH increase via addition of NH4+
a
Oxalic acid was added as substitue for organic C; concentration resembles natural waters (e.g. 20 mg/L DOC-dissolved organic carbon)
b
Uncertainty given contains a balance error of 1%; for tests using oxalic acid, Be was added volumetrically (pipette error of 3% is given)
c
16.2
19.5
7.5
Gives Be amount in supernate after filtering; uncertainty given contains a 5% error of ICP-OES measurement
d
Filter was placed in 6M HCl for several hours to remove Be; solution was dried down and taken up in weak nitric acid for ICP-OES measurement
e
Uncertainty given contains propagated 1σ errors of balance and ICP-OES measurement:
6
Section S4: Qualitative mineralogical information on suspended sediment samples from
depth profiles
Table S2: Qualitative XRD results for DSS samples
Original
Sample
sample code
Quartz
2.Madeira depth profile (water depth in m) a
Mad2-DSS-0m
AM-06-38
++
Mad2-DSS-10m
AM-06-37
++
Mad2-DSS-15m
AM-06-36
++
Óbidos depth profile (water depth in m)
Obi-DSS-0m
AM-06-59
++
Obi-DSS-25m
AM-06-57
++
Obi-DSS-55m
AM-06-55
++
Illite
Chlorite
Kaolinite
Albite
Kfsp
Smectite Halloysite Hematite
+
+
+
+
+
+
-
+
+
+
+/- (microcl)
+/- (microcl)
+
+
+
+
+
+
+
+
+
+
-
+
+
+
+
+
+
+
+
Presence and amount of minerals qualitatively indicating: ++ high, + medium, - low.
a
In absence of enough sample material, XRD was measured on a second Madeira profile sampled on the same day by Bouchez et al. [2010].
Section S5: The chemistry of the reactive phase
Text S4:
In order to characterize the extracted reactive phase, the exact mass of which is unknown, we
calculate the ratio between reactive elemental concentrations ([Element X]reac) and total
elemental concentrations ([Element X]total) for major cations such as Fe, Mn, Al, Ca, Na, Ti, K,
and also Be (Fig. S3). For elemental concentrations of bedload and DSS samples see Tables S3-1
and S3-2. This ratio essentially indicates the fraction of bulk element X hosted in the reactive
phase. As also observed by Wittmann et al. [2012], we observe that Fe, Mn, and Be are hosted
mostly by the reactive phase relative to the total sample, followed (and in some cases
exceeded) by Al and Ca (Fig. S3). The lowest contributions of the reactive phase are found for
Na, Ti, and K. Be is therefore mostly present in the co-precipitated or the adsorbed form in MnFe-oxy(hydr-)oxides. We attribute high proportions of Al and Ca in the reactive phase to the
presence of gibbsite and carbonates, respectively, and hypothesize that our extraction method
only marginally decomposes feldspars and other non-reactive minerals [Wittmann et al., 2012].
We observe similar patterns within each of the following groups of samples, illustrated in Fig.
S3: 1) the Beni and the Madre de Dios (panels A1,2), 2) Madeira and the Amazon (panels B1,2),
3) Brazilian Shield rivers (panel C). Within rivers draining the Guyana Shield (panel D), only the
pattern of Br 7AVG [Wittmann et al., 2012] deviates strongly from those of Br 3 and Ne 0.6. This
group also comprises the largest analyzed grain sizes of 90-250 μm, whereas in the other
groups (panels A, B, C), mostly the 30-40 μm grain size was used. In general, suspended
sediment depth profiles (panels A-2 and B-2, respectively) have more homogenous patterns
than the corresponding bedload samples (panels A-1 and B-1). Qualitative X-ray diffraction for
suspended sediment samples (Table S2) suggest that the mineralogy is much more
heterogeneous than that for bedload samples, as the former also contain illite, kaolinite, and
smectite in addition to quartz, chlorite, albite, and K-feldspar, the latter presented in Wittmann
et al. [2012]. However, bedload patterns show similar trends as depth profiles, with only Na, Ti,
and K even more marginally hosted by the reactive phase of bedload than in suspended
7
sediments. This implies that the contribution of the reactive phase relative to the bulk
elemental budget does not depend strongly on grain size for these elements.
Fig. S3. Composition of the reactive phase as fractions (%) of element concentrations in the
reactive phase ([Element X]reac) relative to total element concentration ([Element X]total,
summed from [Element X]reac + [Element X]min), all calculated relative to initial sample solid
mass). 100% means that the element is hosted only in the reactive (“reac”) phase, while 0%
indicate that the element is hosted only in the mineral (“min”) residual phase. Panels A.1 and
A.2 show results for Andean Rivers analyzed for bedload (A.1) and suspended sediments from
depth profiles (A.2), respectively. Panels B.1 and B.2 are central Amazon bedload (B.1) and
suspended sediment depth profile (B.2) samples, respectively. Panels C and D give bedload
data for Brazilian and Guyana Shield Rivers, respectively. Patterns of Be1AVG (Panel A-1), ObiAVG
(Panel B-1), CB2AVG (Panel C) and Br7AVG (Panel D) are from Wittmann et al. [2012].
8
Table S3-1: Major elemental data for summed leached phases (X-Ox + Am-Ox) and silicate residue (Min) for bedload samples
Summed leached phases (Am-Ox + X-Ox)
Sample
b
Be 1 AVG
Be 2-Rep1
Be 2-Rep2
Be 3
Be 4
Be 8
Be 10
Be 12
MD 15
OR 16
Be 17
Mar 18
Mad 19
Mad 20
GR 19
Pe 101
Pe 107
Man 2.4
Ir 1.75
Par 0.9
Par 1.2
Par 1.6
Par 2.2
Obi AVG
Mad 0.3
Mad 0.5
Mad 1.8
b
Cb 2 AVG
Cb 3
Cb 5
Cb 6
Br 2
b
Grain size
fraction
(µm)
Al
all analyzed
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-40
30-62
30-40
30-40
5510
5610
5370
5230
6140
4520
4380
4810
6800
2900
4690
4250
5670
4150
4470
6320
3120
8470
5570
7390
5330
6160
9990
25500
23800
19400
22000
29700
22000
19800
21700
20100
8210
19500
12200
23900
14600
23800
21000
8150
31500
19900
22800
16700
21300
28600
510
540
520
640
610
370
450
520
590
280
460
470
590
440
590
610
320
570
430
470
440
480
620
2340
1650
1700
1330
1860
780
1630
1310
1800
880
1770
1840
1430
1300
3210
6340
7780
3760
2150
1700
2210
2350
2920
all analyzed
30-40
30-62
30-40
5430
8580
3620
7670
10300
27200
19200
41000
420
520
370
450
all analyzed
30-40
30-62
30-62
90-125
3680
5590
2075
3700
140
6508
11600
2200
7500
420
Fe
K
Ca
Na
a
Silicate residue (Min)
Mn
Ti
Al
Fe
Ti
Mg
78
60
92
67
69
37
67
54
100
54
82
160
59
64
68
230
93
450
160
130
170
240
220
320
280
230
220
280
170
190
200
190
650
180
160
220
170
440
210
130
260
510
190
170
180
290
39
38
19
43
59
42
48
55
150
30
110
35
120
70
12
330
77
1300
190
530
290
540
460
18100
10400
8220
320
4160
18600
4900
10250
250
6110
200
7005
430
39
3650
460
34100
10800
7570
540
6140
40100
23000
7750
6500
8230
190
9890
1460
620
13000
3120
33600
39000
28000
6900
6380
9410
4410
790
6700
7900
770
94
19000
8050
2400
1550
32800
2370
39800
15900
500
31400
7120
11600
9150
3020
12
9240
7100
580
14300
400
590
11400
480
10500
2080
21
3070
48400
28600
36900
32100
7600
14600
14700
620
9200
7030
7700
10040
12100
640
11600
3950
1250
1310
970
960
130
75
68
47
180
330
160
830
150
75
260
110
18250
34200
24800
5430
13800
63500
8900
12700
5330
3300
1450
3670
2410
4710
4640
110
250
1550
2500
9040
30200
1070
2250
2290
220
130
140
200
130
380
300
110
350
10
39
14
14
21
2
75
100
16
540
5
50
43
63
79
30
27000
28600
21100
23800
5800
9100
3600
9320
4380
6550
7560
5710
840
140
290
1130
1000
450
640
1420
210
220
210
360
5890
11500
5750
9940
720
550
480
780
630
430
2700
120
79
14
330
55
-6
(all concentrations in ×10 g/g)
Br 3
125-250
74
130
60
4
1
2
7
Br 4
125-250
130
200
130
5
2
3
10
K
Ca
Na
Mn
(all concentrations in ×10 -6 g/g)
b
Br 7 AVG
all analyzed
2310
560
60
60
7
4
60
2360
4100
3300
90
52
220
4500
50
Ne 0.6
125-250
85
160
160
3
1
1
7
1780
910
16300
32
110
52
990
20
Note that repeatability of ICP-OES measurements is within an uncertainty of 5%, except for K and Na, where for external comparison an uncertainty of 10% should be propagated.
a
Mg conc. of summed leach are not given as they might be biased due to using MgCl 2 in the preceeding step. Si conc. were not determined due to decomposition with HF.
b
Presented concentrations denote averages, please see Wittmann et al. [2012] for details.
Table S3-2: Major elemental data for summed leached phases (X-Ox + Am-Ox) and silicate residue (Min) for DSS samples
Original
sample
a
Summed leached phases (Am-Ox + X-Ox) and silicate residue (Min)
Grain size
fraction
(µm)
Al
Fe
Am-Ox + X-Ox
Am-Ox + X-Ox
18600
15700
52000
43000
750
670
2830
2190
400
270
630
395
195
200
Am-Ox + X-Ox
Am-Ox + X-Ox
29000
17100
55300
44500
1050
580
3970
2840
335
190
695
615
350
290
Min
Min
99000
53000
7900
4400
9370
5440
340
330
5800
3900
45
43
5010
3500
3640
1810
Min
Min
83000
63000
10250
10200
6620
6130
6130
9500
4800
5350
120
173
6100
5200
4050
3740
Am-Ox + X-Ox
Am-Ox + X-Ox
Am-Ox + X-Ox
16200
13200
10500
43000
35000
28000
940
840
670
880
820
710
200
170
120
390
420
406
175
300
140
Am-Ox + X-Ox
Am-Ox + X-Ox
Am-Ox + X-Ox
Am-Ox + X-Ox
Am-Ox + X-Ox
18300
29000
16000
21000
11000
38200
52500
34000
39000
25000
930
1010
870
730
540
1180
4850
2110
4400
1040
325
530
310
390
210
680
735
640
665
440
345
380
273
274
160
Mad-DSS-0m
Am-06-35
susp. sedim.
Mad-DSS-6m
Am-06-34
susp. sedim.
Mad-DSS-12m Am-06-33
susp. sedim.
Óbidos depth profile (water depth in m)
Min
Min
Min
91000
67000
58400
10400
8100
7500
27000
19000
17500
1060
1150
1230
6200
5680
5740
72
72
76
5620
4970
4650
4060
3005
2650
Obi-DSS-0m
Obi-DSS-10m
Obi-DSS-25m
Obi-DSS-40m
Obi-DSS-55m
Min
Min
Min
Min
Min
69000
82000
64000
86000
54100
9890
10500
9500
11700
9370
16300
7020
17000
7600
16000
1840
4970
2290
4905
3150
5410
5870
6480
6540
7200
65
92
84
100
110
4200
4740
4300
4660
3800
3500
4300
3345
4540
3100
code
Beni depth profile (water depth in m)
Be-DSS-1.5m
Am-07-03
susp. sedim.
Be-DSS-4.5m
Am-07-01
susp. sedim.
Madre de Dios depth profile (water depth in m)
Md-DSS-0m
Am-07-14
susp. sedim.
Md-DSS-7m
Am-07-11
susp. sedim.
Beni depth profile (water depth in m)
Be-DSS-1.5m
Am-07-03
susp. sedim.
Be-DSS-4.5m
Am-07-01
susp. sedim.
Madre de Dios depth profile (water depth in m)
Md-DSS-0m
Am-07-14
susp. sedim.
Md-DSS-7m
Am-07-11
susp. sedim.
Madeira depth profile (water depth in m)
Mad-DSS-0m
Am-06-35
susp. sedim.
Mad-DSS-6m
Am-06-34
susp. sedim.
Mad-DSS-12m Am-06-33
susp. sedim.
Óbidos depth profile (water depth in m)
Obi-DSS-0m
Am-06-59
susp. sedim.
Obi-DSS-10m
Am-06-58
susp. sedim.
Obi-DSS-25m
Am-06-57
susp. sedim.
Obi-DSS-40m
Am-06-56
susp. sedim.
Obi-DSS-55m
Am-06-55
susp. sedim.
Madeira depth profile (water depth in m)
Am-06-59
Am-06-58
Am-06-57
Am-06-56
Am-06-55
susp. sedim.
susp. sedim.
susp. sedim.
susp. sedim.
susp. sedim.
K
Ca
Na
Mn
(all concentrations in ×10 -6 g/g)
a
Samples are splits from those analyzed by Bouchez et al. [2010].
b
Mg conc. of summed leach are not given as they might be biased due to using MgCl 2 in the preceeding extraction. Si conc. were
not determined due to decomposition with HF.
Ti
Mg b
Fraction
Sample
9
Section S6: Retentivity correction
Text S5.
Correction of Kd values and comparison between different meteoric-derived denudation rates
You et al. [1989] derived Be partition coefficients from experiments using 7Be across the full pH
range (i.e. chemical equilibrium most likely attained). From this dataset, we calculated a linear
regression (Fig. S4-1) and used this fit to correct our data.
The good agreement between D_METmin/reac-full and the simplified D_METmin/reac’ observed in Fig.
S4-2 indicates that retentivity is high throughout all geomorphic zones of the Amazon basin
and that the bias introduced by sorting effects on the calculation of erosion and denudation
rates is much larger.
Fig. S4-1. Correction of measured Kd values (mL/g) (in grey, calculated from measured [10Be]diss
and [10Be]reac) versus average pH values according to linear fit for the dataset of You et al.
([1989]; dataset itself not shown). Filled grey symbols: bedload samples, grey with red outline
symbols: depth-integrated DSS samples. Green symbols represent the same dataset but
corrected according to linear (green) fit. Note that the same pH values are used for bedload and
DSS data. Resulting corrected Kd values (Table 5 in the main text) are the same for DSS as for
bedload data and only the relative difference between corrected and initial Kd values is different
between the datasets.
10
Fig. S4-2. Denudation rates D_METmin/reac-full (mm/yr; Eq. 13 from main text) and D_METmin/reac’
(using Eq. 15 from main text).
Section S7: Erosion and denudation rates for the Orinoco basin
Text S6:
By using the mass balance approach of von Blanckenburg et al. [2012], we calculated erosion
rates and denudation rates from the data provided by Brown et al. [1992] for the Negro,
Orinoco, Apure, and La Tigra basins (Table S4). A D_METmin/reac-full (Eq. 13 in main text) for the
Orinoco of 0.03 mm/yr was calculated by using [9Be]min data from Negro and Apure samples as
an approximation. This denudation rate compares to an in situ 10Be-derived denudation rate
D_InSitu of 0.06 mm/yr for the Orinoco. For the Negro, a D_InSitu is ca. 0.04 mm/yr (Wittmann
et al. [2011]) We find an overall good agreement between E[10Be]full and D_METmin/reac-full (Table
S4). This good agreement is most likely due to Brown et al. [1992] having analyzed suspended
sediments. The [10Be]reac of these suspended sediments may best represent erosion processes in
the basin.
11
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13