TECHNICAL ARTICLE Secondary Sulphate Minerals in a Cyprus-Type Ore Deposit, Apliki, Cyprus: Mineralogy and Its Implications Regarding the Chemistry of Pit Lake Waters Danae N. Antivachis 1 • Elias Chatzitheodoridis 2 • Nikolaos Skarpelis 1 • Konstantinos Komnitsas 3 Received: 25 June 2015 / Accepted: 29 March 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract The Apliki mine, a Cyprus-type massive sul- phide deposit in Cyprus, was exploited for copper until the mid-1970s. Abandonment of the mine left a deep pit that now hosts a lake fed by surface runoff from the sur- rounding mineralized zone and hydrothermally altered basalt. Oxidation of the sulphide minerals and factors such as climate and terrain relief control the water–rock inter- actions that generate acid mine drainage (AMD), which ultimately affects and defines the quality of the lake waters. Pyrite and chalcopyrite constitute an almost inexhaustible sulphide source that leads to the formation of a variety of secondary iron and copper mineral phases. The secondary mineral assemblages in the ore zone are mainly iron, copper, and magnesium sulphates, whereas the lakeshore assemblage is dominated by magnesium-, calcium-, sodium-, and aluminum-bearing sulphate minerals. Near the lakeshore, the highly soluble iron sulphate salts dis- solve in the lake water, increasing its iron content. Other less soluble salts are more stable and persist in the lakeshore environment. The precipitation and dissolution of efflorescent salts, and, to a lesser extent, the oxidative weathering of the remaining ore minerals, produce addi- tional AMD. Due to the perpetual cycle of mineral disso- lution and precipitation, the lake has a low pH (&3) and contains high concentrations of some contaminants. The processes that contribute to the formation of the efflores- cent mineral assemblages and their environmental impact on pit lake waters, and indeed the complete geochemical system, is a typical example of secondary mineral forma- tion in Cyprus-type Cu-pyrite massive sulphide ore deposits. Keywords Efflorescent minerals Á Acid mine drainage Á Pyrite oxidation Á Cu-pyrite massive sulphide deposits Introduction and Scope The oxidative weathering of pyrite and other sulphides commonly results in the formation of sulphate minerals, the mobilization of metals, and the increase of acidity in sur- face and groundwater environments (Bigham and Nord- strom 2000). The sulphate minerals (efflorescent salts), which are generally formed as products of hydrolysis and evaporation, may incorporate into their crystal structure a variety of metals (Dold 2014; Hammarstrom et al. 2005; Jambor et al. 2000). The stability of the efflorescent sul- phate minerals depends on temperature, relative humidity, and their composition, while reactions involving these minerals can exert a strong influence on the environment (Ranville et al. 2004; Sa ´nchez-Espan ˜a et al. 2005; Valente and Leal Gomes 2009). Their formation, which reflects the interaction of the surrounding rock with surface water and groundwater, has a noticeable impact on water quality Electronic supplementary material The online version of this article (doi:10.1007/s10230-016-0398-0) contains supplementary material, which is available to authorized users. & Danae N. Antivachis antivachis@gmail.com 1 Department of Economic Geology and Geochemistry, Faculty of Geology and Geoenvironment, School of Science, National and Kapodistrian University of Athens, Panepistimiopoli, Zographou, Athens, Greece 2 Laboratory of Mineralogy, Petrology and Economic Geology, Department of Geological Sciences, School of Mining and Metallurgical Engineering, National Technical University of Athens, Athens, Greece 3 School of Mineral Resources Engineering, Technical University of Crete, Chania, Greece 123 Mine Water Environ DOI 10.1007/s10230-016-0398-0