Middle Jurassic age of basalts and the post-obduction sedimentary sequence in the Guevgueli Ophiolite Complex (Republic of Macedonia)

The Guevgueli Ophiolite Complex near Demir Kapija (Eastern Vardar Ophiolitic Unit) was studied for the age and facies of the overlying sediments. Cherts in direct contact with basalts are dated to late Bathonian–early Callovian with radiolarians. The post-obduction sequence, here informally named the Demir Kapija group, is composed of polymictic conglomerate, probably Kimmeridgian in age, and a more than 350-m thick carbonate succession. The carbonate succession consists of hemipelagic, slope and platform margin facies and contains algae and benthic foraminifers indicative of the Tithonian age. These new data support the previously proposed palaeogeographical connection between the Guevgueli and South Apuseni ophiolite complexes.     

Climate Change Impacts on Groundwater Resources in the Coastal Karstic Adriatic Area: A Case Study from the Dinaric Karst

Natural Resources Research - The Bokanjac–Poli?nik system, as a complex set of mutually interrelated Dinaric karst catchments and sub-catchments, is a highly vulnerable and limited...     

Water losses from a reservoir built in karst: the example of the Boljunčica reservoir (Istria,Croatia)

The paper presents the case of the Boljunčica reservoir, which began operation in 1973. It is situated on the Istria peninsula (Croatia). This is a multipurpose reservoir which was built in order to protect the downstream area from flood, to store water for irrigation, and to control sediment transport. The reservoir is situated on the contact zone between water impermeable Eocene flysch and deep Eocene and Cretaceous limestone. The bottom of the reservoir is covered partly by both flysch and quaternary deposits. Water losses from the reservoir bottom are so large that the main service intended for the reservoir, the storage of water for irrigation, is impossible. After every intensive precipitation, which occurs often in this region, the reservoir fills very quickly. The problem is that its retention of water is very short, and lasts only a few days. The water volume of the reservoir at the spillway altitude of 93.00 m a. s. l. is about 6.5 × 10⁶ m³. Because of water losses from the reservoir bottom, the mean annual volume of water stored in it, during the period of 1977–2005 was only 0.5 × 10⁶ m³, which is less than 8% of the full reservoir volume. On the reservoir bottom, many new swallow holes opened through the sediment cover after each time it filled and emptied with water. Special attention is paid to the groundwater level analyses. Interdisciplinary analyses and investigations of hydrological and hydrogeological factors causing the formation of swallow holes and water losses from the Boljunčica reservoir are discussed. The example given in this paper explains one unsuccessful case of building a reservoir in Dinaric karst, caused mainly due to insufficient geological, hydrogeological and hydrological investigations. In order to prevent water losses from the Boljunčica reservoir, very complex and expensive work needs to be done, but its success regarding the reasonable reduction of water losses from the reservoir is in question.     

Book reviews

A phenomenological model of double galaxy dynamics is constructed, assuming a Bohr model for isolated point galaxies bound together in circular orbits by the Newtonian gravitational force. The model is tested by using experimental data from three, independent, random samples of isolated pairs. In each case, the data provides cautious support for the existance of gravitational Bohr orbits in double galaxies, with a mean cosmic Planck's constant/2π given by: $$\langle \hbar _g \rangle \approx 5 \times 10^{74} {\text{erg s }}{\text{.}}$$