Naslov
First insights about Pliocene-Quaternary sedimentation in Neretva River palaeodelta

Autori
Balić, Davorin ; Malvić, Tomislav

Izvornik
Naftaplin : znanstveno-stručno glasilo Hrvatske udruge naftnih inženjera i geologa (1330-2434) 65 (2011); 69-76

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Pliocene; Quaternary; deposition; delta; Neretva; seismic interpretation

Sažetak
Sediments of Pliocene and Quaternary sandstones and siltites are discovered in entire Adriatic Sea, but their distribution is irregular. Pelagic deposits of clays, marls and limestones fill entire basin, but sandy and silty clastites are almost always derived from land and transported by rivers in palaeodeltas. The largest deltas are located along south, Italian Adriatic coast. These are deltas of Po and Adige Rivers in Po Depression, Piave in Venetto Depression and deltas of smaller palaeorivers in Marche-Abruzzi Depression. Pliocene and Quaternary sediments in those areas, with favourable porosity and permeability, are saturated with large volumes of gas, what is proven by numerous field discoveries. On the north coast of Adriatic Sea several larger rivers is located: Soča, Raša, Zrmanja, Krka, Cetina, Neretva and Bojana. However, they did not reach such river flow lengths as mentioned (palaeo) rivers on the Italian coast, especially in Po Depression. Moreover, palaeodeltas on the northern coast could not spread several tens kilometres in subaqueous environment due to irregular coast line and many islands. Only Neretva River delta is of significant size, but also due to strikes of Pelješac Peninsula and Hvar, Sćedro and Brač Islands, possibility of marine deposition have been restricted only on narrow, submarine channels between mentioned islands and peninsula. It is why there are much less thicknesses and spreading of Pliocene and Quaternary then it is observed in Po, Venetto and Marche-Abruzzi. That is reason for assumption than in Neretva palaeodelta differential compaction had not happened, as the main mechanism for forming of structural traps. Also, organic matter was not deposited in critical volumes necessary for biogenic methane generation. The goal of study of Pliocene and Quaternary sediments along northern coast of Adriatic Sea had been insight in development of sandy and silty depositional bodies influenced by palaeorelief. But, possibility for discoveries of gas reservoirs is almost zero. Some reasons such appraisal of the north coast sediments are significantly larger irregularity of coast line then on the Italian side, and large influence of sea level changes especially in Quaternary glacial periods. Exploration had been done based on approx. ten 2D seismic sections, which covered areas among Pelješac, Šćedro, Hvar and Brač, with approximately 1500 km2. There are also used stratigraphic markers from 1 well, distanced approx. 90 km from present Neretva River delta.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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