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During continental break-up and opening of the modern oceans on an Expansion Tectonics Earth, the distributions of species and migration routes were then disrupted, forcing species endemic to the various regions to interact, extend their boundaries, fragment or simply become extinct with time. The timing of ocean development in many of these areas is also reflected in the changes in sea level, facilitating marine faunal migration by extending and expanding immigration routes and moderating climatic differences. ost! species A Degree Fae =r yy tes Ancient Climate The ancient climate on Expansion Tectonics Earth models can be investigated by plotting the distribution of selected climate- The ancient Permian Glossopteris fern is a common dependent rocks and comparing the distribution ossil in coals throughout the southern hemisphere and __ patterns with the location of established ancient poles as traditionally been used to define the ancient and equators. Correlation of coal swamps, thick Gondwana supercontinent. The known distribution of | sandstone sequences and glacial rocks are excellent Clustering —_. Figure 4: Distribution of dinosaur species on a Triassic Expansion Tectonics Earth model showing clustered distributions. These distributions then fragmented as the modern seas opened up and the continents migrated. Glossopteris ferns is centred on localities in South indicators of wet climates, while dry climates are Africa and adjacent India. During the Permian Period, indicated by evaporates, such as salt deposits, and East Antarctica straddled the equator adjacent to South —_ equatorial regions by limestone reefs. Africa, which was surrounded by The glacial record shows four occurrences of Glossopteris major glacial periods, including lora in Australia, West . G . Q the Early and Late Proterozoic Antarctica and India, suggesting The distribution of glacial aeons and the Early and Late Glossopteris flora may also deposits onan Expansion Palaeozoic and Late Cenozoic ave been extensive beneath . . eras. The distribution of glacial he present East Antarctica ice Tectonics Earth IS also deposits on an Expansion cap. useful in checking the Tectonics Earth is also useful in The distribution of Permian 9 0 checking the location of Glossopteris ferns, when location of established established magnetic poles and plotted on Expansion Tectonics magnetic poles... equators plotted from magnetic models, straddles the ancient data. The distribution of many of these Precambrian marine equator and ranges from high- northern to high-southern atitudes. glacial deposits (figure 5), many of which occur in This suggests that Glossopteris ferns were tropical to conjunction with equatorial limestone and iron-rich cool-temperate species, confirmed by the fossil rocks, is an enigma for Plate Tectonics reconstructions. evidence which shows a Gondwana climate In contrast, on an Expansion Tectonics Earth, the commencing with an ice age and passing through acold __ relatively short pole-to-equator distances existing but wet-temperate to warm-temperate climate during during this time allow sea-ice to float readily into the Late Palaeozoic Era. equatorial regions, depositing glacial rock debris These ancient biogeographic examples, while limited, | amongst the existing warm-climatic rocks as it melted— briefly illustrate the ease and simplification of migration hence the current dilemma. and development of all faunal and floral species on an The distribution of Early and Late Palaeozoic glacial Expansion Tectonics Earth. The interrelationships of | deposits coincides with a South Pole located in western global and provincial distributions are then intimately Central Africa (south Gondwana), with isolated maintained without the need for complex conventional mountainous ice-centres located in Europe, Australia continental assemblage—dispersal requirements. and South America. A northward shift in climate Figure 4: Distribution of dinosaur species on a Triassic Expansion Tectonics Earth model showing clustered distributions. These distributions then fragmented as the modern seas opened up and the continents migrated. deposits on an Expansion Tectonics Earth is also useful in checking the location of established 34 * NEXUS JUNE - JULY 2010 The distribution of glacial magnetic poles... www.nexusmagazine.com