8/14/2019 The Massovian Land in Southern Seas

http://slidepdf.com/reader/full/the-massovian-land-in-southern-seas 1/4

THE MASSOVIAN LAND IN

SOUTHERN SEAS

Since we already know that our Michelinoceras swamsomewhere between Pomerania and Scandinavia, let us try tospecify the place in that realm where in the period between460 and 420 million years ago there was a shallow, warm sea

 where those creatures usually lived. And we certainly wouldnot mean the Baltic Sea, as this is one of the youngest seas onEarth which originated no sooner than twelve thousand yearsago. No to mention the fact that in the place of the presentBaltic Sea immense fresh water lake was appearing after the

end of each glacial age, as a result of melting glacier. The lastperiod when such ephemeral lakes occurred was 130-115thousand years ago.

 We should say in the first place that the Earth crust has been inconstant movement throughout its history. The tectonic platescarrying continents interact and shift together, as a result of magma circulation inside the Earth. The magma comes out tothe surface of the lithosphere in the so called rift zones. Thepresent pattern of oceans and continents has been around for³barely´ 15 million years but it changes slowly all the time. Forexample, North America moves away from Europe at a yearly path of 2.5 cm, and the crust under the Massovian land sinks 1mm every year, whereas on the other side of the Baltic Sea, inSwedish Scania, it raises 1.5 mm a year. From the perspectiveof the length of human life a yearly change of one millimeter inthe earth's movement is rather unnoticeable. Similarly, a

period of 60.000 years is like an eye blink from the timeperspective of Earth. Such a period would be needed for theBaltic Sea to come over to the doorstep of Massov, now being62 km away from the sea. Actually, it may happen even earlier,if one considers global warming and an ensuing rise of water level in the oceans. Perhaps, the perspective of the time span of 

8/14/2019 The Massovian Land in Southern Seas

http://slidepdf.com/reader/full/the-massovian-land-in-southern-seas 2/4

a generation to which we usuall limit our reflections onconsequences of our actions, impedes our understanding that

 we may induce the acceleration of certain processes on Earth which in the future could be detrimental to human life or to life

in general. Or possibly, the skeptics are right who say that theforces of nature are too mighty for human actions to have any important meaning and that the Earth would evolveaccordingly to the natural forces, irrespectively of the humanactivity. Let us return to the history of the Earth, on theexample of the Massovian land and to the place and time of 

 birth of our cephalopod.

Let¶s take a look at the above Wiki map of the world from theOrdovician period, when the Orthocerida order separateditself from the older cephalopods, possibly from the family of  Baltoceratidae. We can see that the layout of continents andoceans was quite different than nowadays. All lands in thatperiod were nothing but bare rocks, sands and muds, withsome pattern of arid rivers and lakes. There were first signs of life ± the mosses, appearing now and then, alongside the

 brackish watersides. All animals still lived in the seas, and thefirst bone fish (Osteichthyes) was then the highest developedcreature on Earth. There was in the Ordovician one

supercontinent named Gondwana (which combined thepresent-day Africa, southern Europe, South America, Australia, India and Antarctica), and few other, smaller proto-continents: Laurentia (the current North America andGreenland), Baltica (Scandinavia, northern parts of Russianand the Polish Planes), Siberia, Avalonia and other pieces of 

8/14/2019 The Massovian Land in Southern Seas

http://slidepdf.com/reader/full/the-massovian-land-in-southern-seas 3/4

land.

 We are especially interested in Avalonia, because many factsindicate that the most part of present-day Pomerania rests on

the once Avalonian plate. The Massovian land, submerged inthe sea and located not far away from the South Pole, wasmarked on the map by a red dot. One may assume that at suchlatitudes the Orthoceridas would not enjoy optimal livingconditions, due to cold waters, scarce sunshine and thus notabundant plankton, a prime menu for the ocean shelf creatures. Baltica, situated more to the North and closer to theEquator, seemed to be a more livable place to ourMichelinoceras. The scientists' hypothesis that it originated

from Scandinavia could also be backed up by the fact thatBaltica and Avalonia were separated at that time by a two-to-three-kilometer deep seabed which could not be crossed by shelf animals, who were not very good swimmers. Itshypothetical place of birth was marked by a green dot (I shallreturn to this later).

In the Silurian period (themap comes from the Wiki) that is about 420 million years ago,

 Avalonia ³caught up´ with Baltica, docked to her and formed acommon foundation of the continental plate which tied upPomerania with Scandinavia and the north-eastern part of Poland. The binding of the two proto-continents was followedin the same Silurian period by the collision of Laurentia withBaltica and some time later, with Avalonia. A new super-

8/14/2019 The Massovian Land in Southern Seas

http://slidepdf.com/reader/full/the-massovian-land-in-southern-seas 4/4

continent was born, named Laurussia, extending from today¶sUral Mountains till today¶s Rocky Mountains (both of thosemountain ranges were formed much later).

Please draw your attention to the fact that the Avaloniancraton (or a part of the newly formed continental plate), apartfrom Pomerania on its eastern tip, comprised also today¶sLower Saxony, Benelux, England, southern Ireland, CanadianNewfoundland and the U.S. state of Massachusetts! All theselands have a common rock foundation originating from theOrdovician and Silurian periods. We are talking about thedeepest layer of the Earth's crust which for example under theMassovian land reaches depth of 35 km. The crust is just above

a colder part of the Earth called the mantle (about +700° C)  which reaches a depth of about 100 km. And deeper underthere is the so called asthenosphere, consisting of a semi-liquidmagma of a temperature reaching about +1600°C. We shallnot be stepping down lower « With the laps of time (measuredin millions of years) the oldest rocks were successively covered

 by younger sedimentation layers, in accordance withsubsequent geological periods. We shall talk about it in the

next post.