Geochemistry of Karymsky Volcano System: Field-Work Report

Carlo Cardellini 1 & Salvatore Inguaggiato 2,3

1 Università di Perugia 2 Istituto Nazionale di Geofisica e Vulcanologia, Palermo Italy 3 Istituto di Geofisica UNAM Mexico City, Mexico

Introduction In the framework of the DCO project a geochemical field campaign on the Karymsky

volcano, Kamchatka (Russia) was planned and carried out during the period 17 August -30

August 2012 (Fig. 1).

To organize the geochemical investigation of Karymsky area, the previous geochemical

investigation carried out in this area have been considered and discussed to individuate

the sensible geochemical sites to collect and analyze the fluids.

Fig. 1 – Karymsky volcano – Kamchatka, Russia.

Kamchatka

Petropavlosk

Karymsky

Geochemical work activity

The geochemical activity carried-out during this period was focused mainly in:

1. Geochemical Laboratory work;

2. Fluids sampling (water and gases);

3. C/S plume mesurements

4. CO2 soil fluxes.

1. Geochemical Laboratory work

To prepare and calibrate the equipments, for the collection and measurements of the

fluids (thermal waters and bubbling gases), we enjoy the facility of the chemical

laboratory of the Petropavlosk volcanological Institute.

We preparing the solution of NAOH (4 M) to fill the Giggenbach flasks. Then we make

the vacuum inside of the flasks to are ready for the collection of thermal springs with

bubbling gases.

Moreover, the calibration of pH-meter and Conductivity-meter was performed before to

starting the field campaign.

2. Fluids sampling

During the August 2012, 14 thermal and cold waters in the Karymsky volcano complex

(fig. 2) have been located and sampled. In particular, 7 springs was collected in the

area around the Karymsky river and 7 in the area of Karymsky lake. Water, dissolved

gases and bubbling gases samples have been taken on these fluids manifestations.

Chemical and isotopic composition will be carried out on these samples. Few of these

thermal waters show bubbling gases that have been collected to analyze also the

chemical and isotopic composition (C, He, N2).

The preliminary physic-chemical data of sampled waters showed a wide range of

values. In particular, the outlet temperature shows values between 16 and 94°C; pH

ranges between 5.6 and 9.1 and the electrical conductivity from 70 to 2500

microSiemens/cm (see Table in appendix 1).

These values suggest significant water/rock and gas/water interaction processes, in

fact the lower pH indicates some possible interaction with acid gases while, higher

salinity values (2500 microS/cm) should indicate dissolution processes of wall-rock in

the aquifer.

Fig. 2: Karymsky volcano area with location of sampled fluids.

The measured pH values highlights the presence of two groups of springs:

• Karymsky river springs characterized by acid waters with pH ranging between

5.6 and 6.7;

• Karymsky lake springs characterized by neutral-basic waters with pH ranging

between 7.6 and 9.1.

Moreover, many of these springs are characterized by the presence of bubbling gases

that corroborate the hypothesis of high gas-water interaction processes.

Dissolved and bubbling gases was collected to investigate the origin and the degree of

this gas/water interaction process from a chemical and isotopic point of view.

Finally, in the lake area, two sampling profile 0-60 mt was performed (S1-S2)

respectively in the North (crater area) and Central sides of the Karymsky lake (Fig.3).

Karymsky volcano area

S1

S2

Karymskycrater area

Karymsky river

Karymskylake

In these two profiles, 10 water samples was collected at different depth (0, 10, 20, 30,

40 bottom).

Fig. 3: Karymsky lake area with location of sampled fluids (K6 to K12). S1 and S2

represent the profiles 0-60 mt carried out in the north and central side of the lake area.

At the end of the field campaign all the samples was bring directly at the INGV

geochemical laboratories of Palermo, Italy (S. Inguaggiato) to analyze the chemical

and isotopic composition.

• Chemical composition of waters (Ca, Mg, Na, K, SO4, Cl)

• Isotopic composition of waters (dD, d18O);

• Trace elements;

• Isotopic composition of dissolved and bubbling gases (He, N2, C, Ar).

S1

S2

Karymsky Lake area

Karymskylake

C/S plume measurements

A set of C/S ratio measurements of the plume have been carried out on the flanks of

the volcano (C/S fix) at around 1 Km of distance from the active craters (fig 1). The

measurements was performed utilizing an home made instruments equipped with

double detectors, infrared-spectrometer for CO2 and electrochemical-sensor for SO2.

Soil CO2 fluxes measurements

In the same two areas investigated for the presence of the cold and thermal springs a

CO2 soil fluxes campaign was carried out with around 700 point of measurements to

investigate the presence of a diffuse anomalous degassing.

The CO2 flux measurements were performed by the Accumulation Chamber method

of, using two instruments equipper with an Infra-Red sensor operating in the range 0-

20000 ppm of CO2. Soil temperature at about 10 cm depth was measured at each

CO2 flux measurement point.

Most of the measurements were performed in 3 areas (Fig 4.):

1) Karymsky swamp (along the Karismi river): a grid of ~ 430 measurements of CO2

flux and soil temperature

2) Karymsky Lake, 1997 eruption area: ~ 60 measurements of CO2 flux and soil

temperature

3) Karysmky Lake, thermal area: ~ 130 measurements of CO2 flux and soil

temperature.

The other measurements where performed along the Karimsky river valley and in the

crater area.

Anomalous CO2 fluxes, with values up to 3000-4000 g m-1 d-1, hence clearly referable

to deeply derived CO2, were measured at Karymsky swamp. Lower values, but

probably associated with a weak deep degassing where found also at Karysmky Lake,

Thermal area, while in all the other investigated areas, very low to null CO2 flux were

measured. The data from the Swamp areas and the Thermal areas will be used to

map the spatial distribution of CO2 fluxes from soil to estimate the output of deeply

derived CO2, using appropriate statistical and geostatistical methods.

Fig. 4. Location of the areas investigated for the soil CO2 diffuse degassing and location of

the measurement.