Pannonian Sea Fossils EarthCache

At the listed coordinates you will find sediments from the Pannonian Sea that are rich with fossils. In the past, sand was mined at this location, but the sand mine is abandoned now.

EarthCache

Pannonian Sea

Twenty million years ago, the area of Hrvatsko Zagorje was overflown by a sea. The sea is named Paratethys and it took position over a huge area between the Alps and the Aral Sea. The western and central part of Paratethys became isolated about 12 million years ago and became a huge, separated lake known as Pannonian Sea.

The Pannonian Sea occupied area between the Alps, the Carpathians and the Dinarides, i.e. the area of today's Pannonian Basin. The rivers filled Pannonian Sea with freshwater and over time changed original salinity of sea water into brackish, and finally resulting in freshwater lake. Rivers also brought gravel, sand, and mud from surrounding mountains. Sedimentation of such material over long periods of time led to shallowing of Pannonian Sea and reducing of the area of Pannonian Sea. Finally, some 5-6 million years ago the process of filling up of Pannonian Sea was completed and the Pannonian plane was formed.

Pannonian Sea

Pannonian Sea Fossils

The region of Hrvatsko Zagorje is largely covered by sediments deposited in the ancient Pannonian Sea. The most spectacular outcrop of these sediments can be found in Hum Zabocki. Thanks to the exploitation of sand in the past, a thick succession of sediments has been uncovered, consisting of sands, silts, clays and coal occurrences. These sediments were deposited withing shallow, near shore areas of the Pannonian Sea at the end of the Miocene, a geological epoch which began around 23 million years ago and ended at around 5 million years ago. Later, through geotectonic processes, the initially horizontal sediments were uplifted to the surface and tilted towards the south.

The sediments of Hum Zabocki harbor within them one of the most beautiful and abundant assemblages of fossils in Hrvatsko Zagorje. The most numerous assemblages are those of mollusks and snails, of which over 50 species and subspecies have been identified. Other common fossils include ostracods - crabs of microscopic dimensions, as well as fossils of lacustrine and land dwelling macroflora.

Pannonian Sea Fossils

Sediments at the location are called Rhomboidea beds, and they get their name after one of mollusks species that are found here. These and other mollusks lived around 6 million years ago on the muddy and sandy bottom of shallow near shore areas of the Pannonian Sea. All those species disappeared with the demise of the Pannonia Sea, while their relatives can be found in today's freshwater and brackish lakes across the world.

Logging Tasks

To log this EarthCache answer the following questions:

Send your answers through my profile at geocaching.com (through e-mail or message center) and NOT in a log. You don't have to wait for me to approve your answers. Once you send your answers feel free to log this EarthCache as found. If there are problems with your answers, I will contact you.

Sources

Na izlistanim koordinatama pronaći ćete sedimente koji su nastali u Panonskom moru i koji su bogati s fosilima. U prošlosti, na ovoj lokaciji se eksploatirao pijesak, ali pjeskokop je sada napušten.

EarthCache

Panonsko more

Prije dvadeset milijuna godina, područje Hrvatskog zagorja je bilo preplavljeno morem. To se more nazivalo Paratethys a nalazilo se na ogromnom području između Alpi i Aralskog mora. Zapadni i središnji dio Paratethysa je postao izoliran prije 12 milijuna godina i time je formirano veliko, zasebno jezero koje je poznato po imenu Panonsko more.

Panonsko more se nalazilo na području između Alpi, Karpata i Dinarida, odnosno na prostoru koje se danas naziva Panonska nizina. Rijeke koje su uticale u Panonsko more donosile su velike količine slatke vode, te je tijekom vremena promijenjena slanost morske vode, koja je postala bočata, te je konačno došlo do transformacije Panonskog mora u slatkovodno jezero. Rijeke su donosile i šljunak, pijesak i mulj, čije je taloženje s vremenom dovelo do oplićavanja jezera i smanjenja njegove površine. Prije 5-6 milijuna godina proces zatrpavanja Panonskog mora je dovršen, te je formirana Panonska nizina.

Panonsko more

Fosili Panonskog mora

Područje Hrvatskog zagorja je najvećim dijelom prekriveno sedimentima koji su taloženi u drevnom Panonskom moru. Najljepši izdanak tih sedimenata se nalazi u Humu Zabočkom. Zahvaljujući nekadašnjoj eksploataciji pijeska na površini je otkriven debeli slijed sedimenata sastavljen od slojeva pijeska, mulja, gline i ugljena. Ovi sedimenti su taloženi krajem miocena, geološke epohe koja je započela prije oko 23 milijuna godina, a završila prije oko 5 milijuna godina, u plićim priobalnim dijelovima nekadašnjeg Panonskog mora. Kasnije, djelovanjem geotektonskih procesa, početno horizontalni sedimenti su izdignuti na površinu i nagnuti prema jugu.

Sedimenti kod Huma Zabočkog sadrže jednu od najljepših i najbogatijih zajednica fosilne flore i faune u Hrvatskom zagorju. Najbrojnija je zajednica školjkašai puževa iz koje je određeno preko 50 vrsta i podvrsta. Osim njih, česti su fosilni ostaci ostrakoda - rakova mikroskopskih dimenzija, kao i ostaci jezerske i kopnene makroflore.

Fosili Panonskog mora

Sedimenti na lokaciji EarthCachea se nazivaju i Rhomboidea naslage, a taj naziv je nastao prema jednoj od vrsta školjkaša koja je pronađena na ovoj lokaciji. Ovi i drugi školjkaši su živjeli prije 6 milijuna godina na muljevitom i pješčanom dnu u plitkim, priobalnim dijelovima Panonskog mora. Sve te vrste su izumrle s nestankom Panonskog mora, a njihovi srodnici danas žive u slatkovodnim i bočatim jezerima diljem svijeta.

Zadaci za logiranje

Kako biste logirali ovaj EarthCache odgovorite na sljedeća pitanja:

Odgovore pošaljite preko mog profila na geocaching.com, a NE u Vašem logu! Ne morate čekati na moje potvrđivanje Vaših odgovora. Jednom kada pošaljete Vaše odgovore slobodno logirajte pronalazak ovog EarthCachea. Ako Vaši odgovori budu pogrešni ja ću kontaktirati Vas.

Izvori