In the ancient times „The blood from depths“ was the name for crude oil. From the time of Neanderthals till now this dark liquid has been changing the world. These kind of geomanifestations significantly influenced areas of SW Pannonian basin and Croatia on the whole. The hydrocarbons originate from the deeper parts of the former Pannonian sea/lake (PS) where oxygen levels were low. In those circumstances, dead aquatic organisms did not decompose, but were ultimately covered by tons of sediments brought by rivers and underwater gravity flows. After millions of years oil and gas were formed, and geomanifestations were born.

One of the oldest oil provinces in the world is the Moslavina region. Since the ancient times petroleum seeps called „pakline“ (pakao = hell) were found all over this area. Through history local residents encountered springs of salt water, bubbles on flooded fields and strange black puddles in the depths of lowland forests. The inhabitants of local villages were often horrified by a strange blazing light that mysteriously emerged and disappeared during the night. Today it is known that these strange flames were the consequence of natural gas leakage. Gas was ignited by static electricity at the edges of today’s oil and gas fields. In the Moslavina region, commercial oil exploration dates back to 19th century. First mineshaft called „Martin“ was dug out in 1854 with the depth of 70 m. Oil was dripping out of the rock and was collected into buckets and refined at the nearby factory. This refined oil was used for city lights in the former imperial capital of Vienna.

Discovery and exploitation of oil and gas started fundamental demographic and sociological changes in the appearance of predominantly agricultural regions of the SW part of the Pannonian basin. Many farmers became workers at the oil wells and fields. Oil industry brought safe jobs and supported generations of oilman families in these areas. It also meant industry building, road construction and urbanization of villages. Predominantly illiterate population got a chance for education. Who could have ever imagined that innocent aquatic organisms from long-forgotten Pannonian Sea would have come to life again to play such an important role in the history of Croatia.

Marko Špelić, Tomislav Kurečić and Marko Budić
Croatian Geological Survey – Hrvatski Geološki Institut (HGI-CGS)

References: Based on Špelić, M. and Halamić, J. in „Geology in history“, 2016.

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