by Alexei HERMAN, Dr. Sc. (Geol. & Mineral.), Geological Institute, Russian Academy of Sciences
Our planet's climate has seen continuous changes in the course of geological history, with the most striking changes occurring in the arctic latitudes taking up a major part of Russia's territory. Back in the latter half of the Cretaceous (99.6 to 65.5 mln years ago) the arctic climate was starkly different from what we are having today. The plant and animal kingdoms were quite different, too.
PLANE TREES JUST 1,000 KM FROM THE POLE
The summertime Arctic is dazzling in its vestal beauty. This is the sun up in the clear cerulean skies for weeks on end, the pellucid streams flowing from firn basins, and the blue-green ice mounds and hillocks on rivers that never melt away in short cool summers... A long polar night descends on the Arctic in winter with snowdrifts and ice-bound seas. The subpolar regions of the Far North call up the image of numerous herds of reindeer*, swarms of biting mosquitos and stunted trees here and there**. In spring the arctic tundra plains are out in blossom producing seed during the short growing season so as to give birth to new life next year. Yet things were different in the dim and distant past.
The global climate of the earth of the Late Cretaceous was much warmer than it is today. There were small, if any, ice caps on the poles-at any rate, not so large as today. Thermophilic, heat-loving plants and animals traveled far into high latitudes of the Northern and Southern Hemispheres, and woods spread as far as the latitude of 85° N. That is the Arctic had what looks like a humid, warm temperature climate: the mean warm month temperatures (as calculated by the architecture of leaves of the then extant dicot plants) were in the +17 to +22°C range, and those of the coldest month-between -2 to +9°C, while the mean annual temperatures ranged from +7 to +14°C; the level of monthly precipitation during the growing sea ... Read more