Lõuna-Eesti on Devoni maa. Pärnu-Mustvee joonest lõunas on just Devoni liivakivid need, mis maastikule ilmet annavad. Ja kosmosefotodel paistab kogu see ala punakas.
Devoni ajastu kestis umbes 419-358 miljonit aastat tagasi. Seda ajastut iseloomustavad metsade levik maismaal ja kalade arvukas levik vees. Ajastu lõppes järjekordse suure väljasuremisega.
Eesti Devonit iseloomustab terrigeenne settimine. Sisuliselt tähendab see, et ala kattis madal meri, kuhu ümbritsevatelt maismaa-aladelt uhuti materjali peale. Põhilised kivistised, mida Devoni setetest leitakse, ongi kalad või nende soomused.
Kallaste paljand näitab Kesk-Devoni Aruküla ladet. Avaldatud koordinaatidel asuv infotahvel seletab paljandi lugu täpsemalt.
Leiu logimiseks tulebki minna selle infotahvli juurde ning lahendada sealt (ja internetist) leitu abil järgmised ülesanded:
- Kohalkäimiskontroll: mis numbriga on Kallaste paljand tähistatud Eesti Devoni paljandite kaardil?
- Tahvlil on täpsemalt kujutatud kolm kala, kõik ammu välja surnud. Siiski, ühe neist kauge sugulane ujus 1938. aastal Lõuna-Aafrika vetes kalurite võrku. Tänaseks on teada, et et seda uut sugulast on olemas suisa kaks liiki, üks elab India ookeani lääneosas (Komoorid, Tansaania, Keenia, Mosambiik) ja teine Indoneesias. Mis nime see uus sugulane kannab?
- Mine vaata paljandit lähemal ja kirjelda kivimit. On see lubja- või liivakivi? Mis värvi ta on? On ta peene- või jämedateraline? Kas kivimikihid eristuvad? Kuidas nad paiknevad? Kas kivistisi paistab?
- Ja muidugi võid soovi korral pilte lisada.
Kui vastused käes, saada need peitjale teatena ja pane leiulogi kirja, ära jää luba ootama. Probleemide puhul võtan ise ühendust.
South Estonia is the land of Devonian. South of the Pärnu-Mustvee line Devonian sandstones are the ones that dictate the appearance of the landscape. Also on satellite imagery the area looks reddish.
The Devonian Period lasted from 419 to 358 million years ago. During this period free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. Also, Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes.
The Devonian sediments in Estonia are mostly terrigenic – meaning that the area was covered by shallow sea where materials originating from the surrounding land masses sedimented. The most common fossils found in Devonian sandstones are fish or their fragments.
The Kallaste outcrop is an example of the Aruküla stage of Middle-Devonian. There is an info board at the coordinates that gives proper explanation of the formation and fossils of the outcrop.
To log this as a find you should go to the info board and find from there (and from the Internet) answers to the following problems:
- To prove that you have been here: which number shows the location of Kallaste on the map of Estonian Devonian outcrops?
- There are three fishes shown on the board. All were believed to be extinct ages ago, until a pretty close relative of one of these was caught in South Africa in 1938. Today we know two species from that family, one living in the Western part of the Indian Ocean (Comoros, Tanzania, Kenya), another in Indonesia. What is the name of that fish?
- Go have a closer look at the outcrop and describe the stone. Is it limestone or sandstone? What colour is it? Is the grain coarse or fine? Can you distinguish layers in the stone? How are they located? Can you see fossils?
- And as usual you can add pictures if you wish.
Send the answers through the Message Center and don’t wait for my answer. I’ll contact you once there are problems.
Good luck!