Journal of Volcanology and Geothermal Research 346 (2017) 10–20 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Hydrothermal system and acid lakes of Golovnin caldera, Kunashir, Kuril Islands: Geochemistry, solute fluxes and heat output Elena Kalacheva a,⁎, Yuri Taran a,b, Ekaterina Voloshina a, Salvatore Inguaggiato c a Institute of Volcanology and Seismology, FEB RAS, Petropavlovsk-Kamchatsky 683006, Russia b Institute of Geophysics, Universidad Nacional Autónoma de México, México City 04510, Mexico c IstitutoNazionale di Geofisica e Vulcanologia, Palermo, Italy. article info abstract Article history: Golovnin caldera on the southernmost Kuril Island arc Kunashir Island is characterized by intense hydrothermal Received 5 January 2017 activity and thermal manifestations of different types inside and outside the caldera. In this paper we report our Received in revised form 19 May 2017 results of the 2015 field campaign together with already published data and discuss unusual geochemical fea- Accepted 3 June 2017 tures of the whole system. Acid chloride sulfate waters discharging inside the caldera are different from hot sul- Available online 7 June 2017 fate chloride waters discharging along the coast of the Sea of Okhotsk. The difference is in the ratios of the main conservative components (Cl, B, Na) and a high fraction of a Ca-SO enriched component in the coastal springs. Keywords: 4 Volcano-hydrothermal system Another unusual feature of the system is the existence of boiling Na-Cl springs outside the caldera, between fi Kuril Islands the caldera thermal elds with Cl-SO4 and SO4 acid waters and SO4-Cl acid-to-neutral springs along the coast. Fu- Kunashir marolic and bubbling gases from the caldera are characterized by low 3He/4He values (~3.5Ra), isotopically heavy 13 13 Trace elements CO2 (δ C N −2.6‰) and isotopically light methane (δ C ≤−40‰). This is a rare case when “chemical” (C-H-O) REE temperatures are higher than the “isotopic” (CO2-CH4) equilibrium temperatures. Trace element hydrochemistry Stable isotope geochemistry shows preferential congruent rock dissolution in ultra-acid steam-heated SO waters inside the caldera and more 3 4 4 He/ He complicated water-rock interaction for other types of waters. The REE patterns for chloride-sulfate and sulfate- chloride waters normalized by average rock show depletion in LREE caused, most probably, by co-precipitation of LREE with mineral assemblages characteristic for argillic and advanced argillic alteration. The only source of chloride in the drainage from the Golovnin caldera is the Kipyaschee Lake (Cl-SO4 hot springs on the lake bottom and at its shore). Solute output from the Golovnin caldera is lower than that from the other studied volcano-hy- drothermal systems of Kuril Islands (5.7 t/d of Cl and 7.3 t/d of SO4). Natural heat output by hot water and steam discharges is estimated as 63 ± 20 MW. © 2017 Published by Elsevier B.V. 1. Introduction campaign that include chemical and isotopic data for waters and gases from the thermal manifestations of the system and caldera lakes, the The Golovnin caldera (43°N, 150°E) is the southernmost volcanic total discharge of thermal waters and the solute output from the structure of the Kuril Island arc. It hosts two acid lakes and an active hy- whole system. All types of waters were analyzed for major and trace el- 18 16 drothermal system discharging Cl-SO4 and SO4 hot acid waters and ements and D/H, O/ O isotopic ratios. Gas samples were analyzed for 13 12 3 4 steam inside the caldera and acid-to-neutral hot waters outside the cal- major species, He and Ar, as well as for C/ CinCO2 and CH4, He/ He dera. Several studies are known on the hydrochemistry of this system, and 40Ar/36Ar. Based on our and published data we propose a prelimi- most of them were published decades ago in almost inaccessible Rus- nary model for the system. sian sources (Sidorov, 1966; Zotov and Tkachenko, 1974; Markhinin and Stratula, 1977 among others). Chudaev et al. (2008) published a 2. General settings short review about the hydrothermal systems of three Kuril Islands with a limited set of data for Golovnin caldera. A dozen of chemical The Golovnin caldera is located at the south of Kunashir Island, the and isotopic analyses of waters from the Golovnin caldera can be southernmost island of the Kuril chain, separated from Hokkaido by found in Zharkov (2014). Kozlov (2015) made a bathymetric survey of the Nemuro (Kunashir) Strait, 16 km wide at the narrowest place. The both caldera lakes. Here we report our results of the 2015 field last Golovnin caldera-forming eruptions, according to Braitseva et al. (1994) occurred ~40 Ka ago. The caldera is about 6 km in diameter, 2 fl ⁎ Corresponding author. with an area of 27 km and the caldera oor at ~130 m above sea E-mail address: [email protected] (E. Kalacheva). level (asl). The caldera rim, 400–500 m asl, is cut by a canyon of the http://dx.doi.org/10.1016/j.jvolgeores.2017.06.001 0377-0273/© 2017 Published by Elsevier B.V. E. Kalacheva et al. / Journal of Volcanology and Geothermal Research 346 (2017) 10–20 11 Ozernaya River (Fig. 1). Four extrusive domes within and one outside composite column at room temperature. The analytical error was ~5%. the caldera extend along a line in the SE-NW direction (Fig. 1). The Dry gas was used for the analysis of carbon isotopes in CO2 and CH4. Kipyaschee (Boiling) Lake with an area of 0.045 km2 is drained by the He and Ar isotopes and He/Ne ratios were analyzed in the headspace 400 m-long Sernyi (Sulfur) Creek to the Goryachee Lake that has an gases of Giggenbach bottles. area of ~3 km2. The latter is drained by the 3 km-long Ozernaya Stream Water samples were filtered in situ through 0.45 μm filters and col- to the Sea of Okhotsk. Both lakes are fed by hot fluids from the lake bot- lected in plastic bottles. Temperature (±0.1 °C), pH (±0.05 units) and toms and from thermal fields on the lake shores. There are several ther- conductivity (±2%) were measured on site by an Orion multimeter. mal fields inside the caldera at shores around of the Goryachee Lake Samples for major cations and trace elements analyses were acidified with steam vents, boiling pools, mud pools and low-discharge hot bub- with ultra-pure nitric acid. Concentrations of major dissolved species bling springs: Bezymyannoe (Nameless) Field, Cherepakhovoe (Turtle) (Na, K, Ca, Mg, F, Cl, SO4) were determined using ionic chromatography. Field and Central West Field (CW). Besides, many bubbling spots can be Alkalinity as HCO3 was measured by titration using a 0.1 M HCl solution. seen on the lake surface. The Kipyaschee Lake, according to Markhinin Total SiO2 and B were determined by colorimetric method using ammo- and Stratula (1977), is a young (~1 Ka) maar formed by hydrothermal nium molybdate (Giggenbach and Goguel, 1989) and carminic acid, re- eruption. There are also several hot springs and steam vents on the spectively. The analytical errors were usually b5%. Concentrations of shore of the Kipyaschee Lake, as well as numerous vents on the lake trace elements were determined by ICP-MS (Agilent 7500 CE) in the In- floor. This thermal area is named the Central Eastern Field (CE). Outside stitute of Ore Deposits, Moscow. All determinations were performed the caldera, several groups of thermal springs named the Alyokhinskie with the external standard calibration method, using Re and In as inter- springs stretch for ~2 km along the coast line of the Sea of Okhotsk nal standards. The accuracy of the results (±5%) was obtained by ana- (Fig. 1). The nearest to the caldera group of springs (AB – Alyokhinskie lyzing certified reference materials (NRCSLR-4, SPS-SW1 and NIST- Boiling) consists of two thermal fields: Lower field and Upper field. Sev- 1643e). The water samples were analyzed for their oxygen and hydro- eral vents of the Lower Field discharge boiling water on the sea shore. gen isotopic composition, using “Los Gatos” spectrometer in the Insti- The Upper Field, at ~200 m asl, is characterized by steaming grounds, tute of Volcanology and Seismology, Kamchatka, Russia. The isotope several small mud pools and weak steam vents. Three main thermal ratios are expressed in permil vs V-SMOW. The uncertainties are fields, CW, CE and AB, are associated with the extrusive domes (Fig. ±0.2‰ for δ18Oand±1‰ for δD (one standard deviation). Carbon iso- 1). Further to the NE along the coast there are two more groups of hot topes in CO2 and CH4 were determined using a Finnigan Delta Plus XP springs: South Alyokhinskie (AS) and North Alyokhonskie (AN) (Fig. 1). continuous-flow IRMS coupled with a TRACE gas chromatograph sys- tem equipped with a Porabond Plot capillary column (60 m., ID 3. Methods 0.32 mm) with accuracy 0.2‰ in the Institute of Geology, UNAM, Mexico. Steam vent and bubbling gas samples were collected using Titanium Helium isotopes and He/Ne ratios were analyzed by a static vacuum or plastic funnel, Giggenbach bottles and 10 ml vacutainers with septa mass spectrometer (VG-5400 TFT, VG Isotopes) in the INGV—Palermo. stopcocks. Gas samples from Giggenbach bottles were analyzed follow- 3He/4He ratios were corrected for the atmospheric contamination on ing the method described by Giggenbach and Goguel (1989).Headspace the basis of the difference between 4He/20Ne of the sample and that of gases from Giggenbach bottles and dry gas from vacutainers were ana- the air (Sano and Wakita, 1988).