<p><strong>Abstract.</strong> This study reviews and synthesises existing information generated within the SCOPSCO ("Scientific Collaboration on Past Speciation Conditions in Lake Ohrid") deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismotectonic history, (iii) volcanic activity and climate change in the central northern Mediterranean region, and (iv) the drivers of biodiversity and endemism. The Ohrid basin formed by transtension during the Miocene, opened during the Pliocene and Pleistocene, and the lake established de novo in the still relatively narrow valley between 1.9 and 1.3 Myr ago. The lake history is recorded in a 584 m long sediment sequence, which was recovered within the framework of the International Continental Scientific Drilling Program (ICDP) from the central part (DEEP site) of the lake in spring 2013. To date, 50 tephra and crypto-tephra horizons have been found in the upper 460 m of this sequence. Tephrochronology and tuning biogeochemical proxy data to orbital parameters revealed that the upper 247.8 m represent the last 637 kyr. The multi-proxy dataset covering these 637 kyr indicates long-term variability, with a change from cooler and wetter to drier and warmer glacial and interglacial periods around 300 ka. Short-term environmental change caused, for example, by tephra deposition or the climatic impact of millennial-scale Dansgaard-Oeschger and Heinrich events are superimposed on the long-term trends. Evolutionary studies on the extant fauna indicate that Lake Ohrid was not a refugial area for regional freshwater animals. This differs from the surrounding catchment, where the mountainous setting with relatively high water availability provided a refugial area for temperate and montane trees during the relatively cold and dry glacial periods. Although Lake Ohrid experienced significant environmental change over the last 637 kyr, preliminary molecular data from extant microgastropod species do not indicate significant changes in diversification rate during this period. The reasons for this constant rate remain largely unknown, but a possible lack of environmentally induced extinction events in Lake Ohrid and/or the high resilience of the ecosystems may have played a role.</p>

SummaryGeorgeite, an amorphous copper carbonatehydrate, has been found in the oxidation zone of the Carr Boyd nickel deposit, Western Australia. It forms thin coatings mostly associated with malachite and chalconatronite on partly weathered tremolite rock containing disseminated copper and iron sulphides.Physical properties: Colour light blue, streak pale blue, lustre vitreous to earthy, fracture conchoidal, soft, sp. gr. 2.55; transparent to sub-opaque (aggregates), n(NaD) = 1.593, isotropic. Amorphous to X-rays and electron beam.Chemical microanalysis gave (wt%) CuO 54.9, ZnO 0.4, Na2O 2.7, CO2 20.8, H2O 21.7, sum 100.5. After deduction of all Na2O and corresponding amounts of CuO, CO2, and H2O as chalconatronite (12.35 wt%) the atomic ratios correspond to an empirical formula (Cu5.0, Zn0.05)(CO3)3(OH)4.12.6.3H2O, the ideal formula being Cu5(CO3)3(OH)4.6H2O.

Comparison of the infrared spectra of georgette and a phase which can be reproducibily synthesised in the laboratory shows that the mineral is an amorphous analogue of malachite, Cu2CO3(OH)2. Synthetic studies also explain the chemical conditions under which georgette may form, as well as those which can cause it to react to either malachite or chalconatronite. Parallels may be drawn between the laboratory observations and known mineral associations of georgette.

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