scholarly journals Karst and geotops of karst origin in Albania

2018 ◽  
Vol 34 (2) ◽  
pp. 811
Author(s):  
A. SERJANI ◽  
H. HALLACl ◽  
A. NEZIRAJ ◽  
A. HALLACl
Keyword(s):  
Sea Level ◽  
Carbonate Rocks ◽  
Developed Countries ◽  
Karst Development ◽  
Salt Rocks ◽  
Karstic Lakes ◽  
Albanian Alps ◽  
Carbonate Formations

Albania is one of the most karst-developed countries in Europe. Karst phenomena are related to soluted carbonate formations which cover of about 7300 km2 of Albanian territory and with sulfate evaporates rocks, which outcrop of about 500 km2. Typically alpine relief of average altitude 708 m above the sea level and high horizontal splitting are favorable for karst development. Karst and geological sites of karst origin are widespread mainly in Albanian Alps and in Ionian zone. In Albanides there are determined surfaces and underground karst forms which belong to the Neo-Pliocene-Quaternary age and deep karst forms belonging to the paleokarst in old formations. The most widespread karst forms in carbonate rocks there are valleys, caves, cones etc., while into salt rocks there are formed many karstic lakes and depressions. Up to now there are determined about 80 karstic caves, nice karst fields, valleys, plains, which represent geological sites of karst origin.

The pattern of the tectonic joints and the development of the Vlychada karst show cave in Diros, Peloponnesus, Greece

2021 ◽  
Author(s):  
Christos Filis ◽  
Emmanuel Skourtsos ◽  
Nikolaos Karalemas ◽  
Vasilios Giannopoulos ◽  
Ioannis Giannopoulos ◽  
...  
Keyword(s):  
Characteristic Feature ◽  
Sea Level ◽  
Carbonate Rocks ◽  
Meteoric Water ◽  
Weather Conditions ◽  
High Angle ◽  
Tectonic Structures ◽  
Joint System ◽  
Factors Influencing ◽  
Show Cave

<p>The most characteristic feature of carbonate rocks is that they are prone to dissolution due to the meteoric water circulation which is enriched in CO<sub>2</sub>. One of the factors influencing this phenomenon is the existence of discontinuities within the mass of carbonate rocks. The Diros Vlychada show cave, on the peninsula of Mani in Peloponnese, Greece, has developed in marbles that belong to the Plattenkalk geotectonic unit. Most of the cave is flooded with water and its level changes depending on the external weather conditions and variations in sea level. The deformation of the marbles is represented by tectonic structures formed during the Lower Miocene metamorphism and their subsequent exhumation. The final uplift stage took place during the Pliocene-Quaternary and is still active. Five joints systems were distinguished:</p><p>A NW-SE joint system which is subdivided into a subsystem with low-angle dips, mainly towards to the NW, related to the main foliation of the marbles and a second subsystem characterized by stretching joints of the same strike (elongated joints), which have high-angle dips, also towards the NW. The latter system intersects the former but is confined between marble bedding and does not extend to more than three beds (the bedding is defined by the first subsystem).</p><p>A NW-SE striking joint system characterized by stretching joints with high-angle dips, which intersects diagonally the two previous. This system extends between more than three marble beds.</p><p>Two systems show E-W and N-S strike with the first one much better expressed. Those joints have developed diagonally to the previous ones. These are mainly shear joints that intersect the first system and are propagated within many marble beds.</p><p>The chambers of the cave have been developed along NW-SE and E-W directions. The first one is identified with the joint system that has been developed transversely to the strike of the marble foliation and the second in parallel with the main system of the shear joints. It is interesting that the bays forming the coastline of the Mani peninsula, have developed in an E-W direction, which coincides with both one of the growth directions of the cave and one of the joints systems, which correspond to shear joints developed during the folding of the marbles. Stalactites and stalagmites grow in a NE-SW direction that is identical to the elongated joints which form the system that is parallel to the foliation strike. Groundwater flow along these branches may be slower as these branches appear to be restricted between marble bedding.</p>

Characteristics and its Environment Implications of Carbon and Oxygen Isotopic of Ordovician Carbonate Rock in Yubei Area

2015 ◽  
Vol 1092-1093 ◽  
pp. 1375-1378
Author(s):  
Qian Zhang ◽  
Wen Hui Huang ◽  
Ya Mei Zhang
Keyword(s):  
Sea Level ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Burial Depth ◽  
Oxygen Stable Isotopes ◽  
Oxygen Isotopic ◽  
Oxygen Stable Isotope ◽  
The Stability ◽  
Diagenetic Environment ◽  
Stable Isotope Data

Based on a large number of carbon and oxygen stable isotope data, researched environment characteristics of Ordovician carbonate rocks in Yubei area, Tarim Basin. According to carbon, oxygen stable isotopes (&13C, &18O) data, combining the diagenetic environment characteristics studied all kinds of geochemical characteristics of rocks in Yubei area. The research results show that: Paleosalinity feature of Ordovician carbonate rocks in this area reflected the carbonate rocks is formed in the stability of the marine environment and basically kept the composition of carbon and oxygen isotopic of the original environment. the paleo temperature characteristics indicate that the diagenetic burial depth was increased first and then decreased, the sea level characteristics indicate that the sedimentary strata by Yingshan period to Lianglitage period corresponds with a rise in sea level.

scholarly journals Consistent experimental investigation of the applicability of Biot-Gassmann’s equation in carbonates

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. WA97-WA113 ◽  
Author(s):  
Elisabeth Bemer ◽  
Youri Hamon ◽  
Mathilde Adelinet
Keyword(s):  
Carbonate Rocks ◽  
Sedimentary Facies ◽  
Solid Matrix ◽  
Acoustic Response ◽  
Velocity Measurements ◽  
S Wave ◽  
Gassmann’S Equation ◽  
Nonpolar Fluids ◽  
Carbonate Formations ◽  
Diagenetic History

Carbonate formations are characterized by multiscale heterogeneities that control their acoustic response and flow properties. At the laboratory scale, carbonate rocks do not indicate a strong correlation between P- and S-wave velocities and porosity. The velocity disparities between carbonates of similar mineralogy and porosity result from different microstructures derived from their sedimentary facies and subsequent diagenetic transformations. The still-discussed applicability of Biot-Gassmann’s equation for fluid substitution in carbonate rocks remains another key issue. We have developed an integrated experimental workflow that allows a consistent checking of the applicability of Biot-Gassmann’s equation and provides key geologic and microstructural information to understand the petroacoustic signature of carbonate rocks. The defined approach is based on the phase-velocity measurements performed in liquid-saturated conditions using polar and nonpolar fluids. It allows the identification of the whole set of parameters required by Biot-Gassmann’s equation including the bulk modulus of the solid matrix. This approach is implemented on samples representative of two different carbonate formations deposited in lacustrine and marine environments, respectively. The obtained results demonstrate the applicability of Biot-Gassmann’s equation for the two studied carbonate families and indicate the link between their petroacoustic signature and diagenetic history.

scholarly journals Laboratory Testing of Novel Polyfraction Nanoemulsion for EOR Processes in Carbonate Formations

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4175
Author(s):  
Piotr Kasza ◽  
Marek Czupski ◽  
Klaudia Wilk ◽  
Mateusz Masłowski ◽  
Rafał Moska ◽  
...  
Keyword(s):  
High Pressure ◽  
Oil Recovery ◽  
Carbonate Rocks ◽  
High Efficiency ◽  
Core Flooding ◽  
Reservoir Water ◽  
High Pressure High Temperature ◽  
Eor Processes ◽  
Carbonate Formations ◽  
Physical Phenomena

Nanoemulsions and polymers are widely used for increasing the efficiency of enhanced oil recovery (EOR) processes. The application of both these additives enables the synergistic use of several physical phenomena that are crucial to the process. One of the methods used for assessing these processes is laboratory core flooding tests using natural cores. In various experiments, carbonate rocks are subjected to oil displacement under high pressure and temperature. Polymer solutions and a newly developed polyfraction nanoemulsion are tested. The test results confirm the usefulness of these products for EOR processes and demonstrate their stability under high pressure, high temperature, and in the presence of H2S. Under these conditions the polymers maintain high efficiency in displacing crude oil from carbonate rocks, while the tested nanoemulsion improves the wettability of carbonate rocks and reduces interfacial tension, factors which increase the efficiency of oil displacement.The best result in the laboratory EOR simulation was obtained for polymer and nanoemulsion concentrations in dilute reservoir water of 0.05% and 1%, respectively. In this case, the measured oil recovery was 37.5% higher than that obtained when using water without additives.

scholarly journals Probable Maximum Precipitation in Iceland – Station Values –

1992 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Jónas Elíasson
Keyword(s):  
Engineering Design ◽  
Sea Level ◽  
Service Time ◽  
Developed Countries ◽  
The Other ◽  
Probable Maximum Precipitation ◽  
Maximum Precipitation ◽  
Sloping Terrain ◽  
High Series ◽  
Meteorological Models

The meteorological stations in Iceland are rather few compared to the size of the country, and their service time is short compared to other developed countries. Investigations of individual 24-hour station PMP values computed by the Hershfield and NERC methods show trends that are important for the application of PMP values in engineering design. The results fall into two series, one with high PMP values and the other with lower values. The low values originate from station groups situated in areas with mildly sloping terrain and here the results compare fully with what should be expected from experience from other countries. The other series shows results that do not compare as well with previously published results. Their general characteristics is that PMP values calculated hy the Hershfield method are of the order 80% higher than the corresponding results obtained by the NERC method. The results of this high series do not check against results obtained from meteorological models. It is noteworthy, that all the stations of the low series belong to station groups where the terrain is gently sloping, i.e. average terrain slopes less than 1.4%, while in the high series all the stations belong to station groups where the terrain slopes steeply from a highland plateau down to sea level. It is concluded that the generalized estimates of PMP values needed in engineering design could be obtained.

scholarly journals Ordovician stratigraphy of the Kovel-1 well (Volkhov–Haljala) in the Volynia region, northwestern Ukraine

2004 ◽  
Vol 51 ◽  
pp. 47-69
Author(s):  
Tõnis Saadre ◽  
Rein Einasto ◽  
Svend Stouge
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Carbonate Rocks ◽  
Carbonate Sediments ◽  
Middle Ordovician ◽  
Tectonic Events ◽  
Depositional Cycles ◽  
Open Shelf

The Ordovician succession of the Kovel-1 well in the Volynia region, northwestern Ukraine is composed of a basal 0.6 m thick siliciclastic unit succeeded by 24.7 m Lower and lower Middle Ordovician carbonate sediments. The carbonate rocks are divided into 13 informal lithologic units. The carbonate sediments accumulated in marine shallow water open shelf and shoal or turbulent environs. Biostratigraphically, the succession is referred to seven chitinozoan zones and 12 conodont biozones. Integration, chronostratigraphic position and correlation of the proposed biozones with those from Baltoscandia are briefly discussed. Four major unconformities are recognized within the succession: 1) the Pakerort(?)–Volkhov unconformity, 2) the mid Volkhov unconformity, 3) the early Kunda unconformity and 4) the early Mid Ordovician hiatus. The latter straddles the Oeland–Viru regional Series boundary in the well. The early Mid Ordovician unconformity is prominent and the corresponding hiatus spans the Aseri and Lasnamägi regional stages (= upper Darriwilian). A complex of cyclic transgressive–regressive depositional pattern prevailed and the whole succession is referred to three major depositional cycles. The major depositional cycles are related to global eustatic sea-level cycles in general and hypothetic way to tectonic events caused by collisions of Peri-Gondwanan microcontinents with Baltica.

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