Fig. 1. Sketch map of the LH with locations of features discussed in the text. The inset map shows the position of the LH in Antarctica, the major peninsulas and islands that comprise the LH, and the location of the 4 Stornes sites (Long Lake, Lake Heidi, Lake 24 and Lake 25). The map of Mirror peninsula shows the location of the 4 research stations, some topographic details (contours and elevations in meters above sea level), position of lakes discussed in the text (light stippled), vehicular tracks, and other prominent features. Horizontal stipples indicate areas strongly impacted by station activities. Vehicular tracks also correspond to the main walking tracks. Map modified from Gasparon and Matschullat (2006).

Fig. 2. a–e. Comparison of elemental concentrations extracted from the <0.63 mm sediment fraction using procedures A, B, C and D in 6 samples (Fig. 2a – sample IN21; Fig. 2b – sample IN26; Fig. 2c – sample IN27; Fig. 2d – sample IN28; Fig. 2e – sample IN29). The “Relative concentration factor” is calculated as the ratio between concentrations measured using procedures B, C and D, and those measured in procedure A, hence values for the A samples are equal to 1. Arbitrary values (corresponding to detection limits) had to be assigned where measured concentrations were below detection limits, and therefore the trends displayed by these figures are largely an artefact. Values for elements not reported in Table 1 (Li, Be, Ga, Nb, Ag, In, Sn, Sb, Tl and Bi) are available in the electronic version of this article.

Fig. 3. Pb/U vs. Pb values in LH basement lithologies (open circles) and leachates from Table 1. LH basement data from Gasparon and Matschullat (2006). Field labelled UC represents the composition of upper crustal material, and including typical clastic sediments and soils (data from Taylor and McLennan, 1985, Reimann and de Caritat, 1998 and McLennan, 2001). Note the high Pb levels in D leachates (solid squares), and the positive linear correlation between Pb/U and Pb values in D leachates, indicating partial digestion of primary mineral phases.

Table 1.

Trace element concentrations in <63 μm sediment fractions

All element concentrations in μg/g.

The number (1996 or 1997) next to the sample location refers to the year of sampling.

BS – “bottom sediment” sample, collected 20–40 cm below the water surface.

ND = not determined.

Modified = modified leaching procedure (see text).

Typical RSD are 1–5% for elements in bold, and 3–10% for the other elements.

Additional data is available in the electronic version of this article.

Table 2.

Sediment leaching data

Physical parameters are electrical conductivity λ (in μS/cm) and pH, measured in the E (λ, pH – E) and C solution (pH – C), respectively.

All element concentrations in μg/g.

The number (1996 or 1997) next to the sample location refers to the year of sampling.

BS – “bottom sediment” sample, collected 20–40 cm below the water surface.

<DL = below detection limit.

Averages and standard deviations calculated assuming that values <DL are equal to 0.5^aDL.

Detection limits based on 3σ of blank values.

Concentrations of As, Pb, Sb, and Se were measured but were below detection limits (30, 10, 50, and 30 ppb, respectively) for all samples.

Additional data (including blanks, duplicates, and Ag, Cd, P, Sr, V, and Si values) is available in the electronic version of this article.

^a Values calculated excluding sample IN7.

Table 3.

Organic matter leaching data

All element concentrations in μg/g.

The number (1996 or 1997) next to the sample location refers to the year of sampling.

In volume % = approximate proportion of mineral matter mixed with the sample (±10%).

<DL = below detection limit.

d = procedural duplicate.

Detection limits based on 3σ of blanks values.

Additional date (including blanks, and As, Sb, Cd, Sr, and V values) is available in the electronic version of this article.

Table 4.

Summary data

All concentrations in μg/g.

Data calculated assigning an arbitrary value of 0.5xDL for values <DL.

“Moss <5” and “Algal mat <5” indicate, respectively, moss and algal mat containing less than 5% inorganic matter.

Table 5.

Calculated and observed rates of sediment deposition, and Pb and Ba concentrations in LH lake waters and sediments

^a From Gillieson et al. (1990).
^b From data and sediment logs reported in Hodgson et al., 2001 and Sabbe et al., 2004.
^c Calculated using erosion data from Spate et al. (1995), and assuming that 100% of the sediment derived from the catchment is deposited in the lake.
^d Estimated from core logs reported in Gillieson et al., 1990 and Hodgson et al., 2001, and field observations by M. Gasparon.
^e From calculated/observed clastic sediment ratio.
^f From data reported in Gasparon and Burgess (2000).
^g Calculated using the plagioclase dissolution model discussed in Gasparon and Matschullat (2006), catchment and lake areas and volume estimated from data reported by Gillieson et al. (1990), and residence times in the water column calculated by Gasparon (2001).
^h Average and minimum-maximum values (in brackets) calculated from data reported in Table 4 and based on the observed range of clastic/organic sediment (algal material 1–10 wt% of the total sediment).
ⁱ Average and minimum-maximum values (in brackets) calculated using the plagioclase dissolution model discussed in Gasparon and Matschullat (2006) for plagioclase content ranging from 10% to 30%, and a bulk density of 1.6 g cm⁻³; these values are not site-specific and are not a function of erosion rates. Calculated Pb and Ba concentrations in lake waters and sediments were obtained assuming that plagioclase is the only significant source of dissolved Pb and Ba (leachable using procedures E, C, and F) into the lake waters and sediments. Pb and Ba concentrations in plagioclase used for calculations are from Smith and Brown (1988) (range of values for coarse-grained igneous and metamorphic rocks).