Changing the way we look at the world
A creation model of dinosaur biogeography
I have not written much for this blog for a while and the reason is that I have been researching palaeobiogeography (the study of the geographic distribution of fossils). This is linked to the subject of my post about the break-up of the single continent (Pangaea) in the days of Peleg.
In particular, I am looking at the palaeobiogeography of dinosaurs.
There are many different species of dinosaurs (and other terrestrial vertebrates) found in Cretaceous rocks on all the continents of the world.
How did they get there? They did not appear in all these places at the same time. They would have started off in one place and spread out across the globe.
Palaeontologists suggest various mechanisms, such as dispersal, land bridges and vicariance. The picture is complicated by various factors including the timing of the break-up of Pangaea and the first recorded fossils of each dinosaur species. (Pangaea was the single continent which was believed to have broken up at the same time as the Cretaceous rocks were formed). Vicariance (or splitting of areas) is one explanation for the existence of the same type of dinosaurs on different continents which are widely separated today. For example, similar dinosaurs are found in South America and Africa. According to the vicariance model these continents were joined and the dinosaurs were living on what was to become South America and Africa. The timing of the break-up of Pangaea makes this one of the best explanations for fossil dinosaur distributions on these two continents.
Dispersal across the oceans on mats of floating vegetation has also been proposed. However, while this mechanism could work for small and medium sized animals it seems unlikely for large dinosaurs like, for example, the titanosaurs.
Transient land bridges have also been proposed to explain some of this distributions or fossil and living animals.
Young Earth creationist palaeontologists have also tried to explain the distribution of animals that we see today. Although they have not looked at the distribution of dinosaurs. The distribution of dinosaurs is difficult to explain if one holds to the most popular creationist geological models which suggest that most, if not all, Cretaceous rocks are flood rocks.
If Cretaceous rocks were deposited towards the end of the flood year, then dinosaurs must have been buried during the flood year. If we look at the dinosaur fossil record this seems unlikely. There are fossil dinosaur nests with eggs, some of which have been found to contain fully developed baby dinosaurs about to hatch out. There are many dinosaur footprints all over the world which show that the dinosaurs were walking around on various layers of Cretaceous rocks, which were subsequently covered by other layers of Cretaceous rocks. These processes take time, more time than is available at the end of the flood year. Also, it would have been impossible for dinosaurs to build a nest, lay eggs and incubate them, while the land was covered by the waters of the flood. There are also fossils showing the diversification of dinosaurs at this time, for example the trend to larger size, which would require hundreds of years at a minimum.
If the Cretaceous rocks were laid down after the flood, then the fossil dinosaurs are descendants of the dinosaur kinds which came off Noah’s ark. This model also involves the break-up of Pangaea many years after the flood (in the days of Peleg).
If this is the case then the answer to the question of why we find the same type of dinosaur on different continents could also be explained by one or all of the mechanisms of dispersal, land bridges and vicariance. Dispersal after the flood can also explain the diversification of dinosaur kinds after the flood.
As I research this subject, I will be posting about it in the new year, but as there is a massive amount of literature to read so it will be a slow process. Hopefully it will be worthwhile.
I have not written much for this blog for a while and the reason is that I have been researching palaeobiogeography (the study of the geographic distribution of fossils). This is linked to the subject of my post about the break-up of the single continent (Pangaea) in the days of Peleg.
In particular, I am looking at the palaeobiogeography of dinosaurs.
There are many different species of dinosaurs (and other terrestrial vertebrates) found in Cretaceous rocks on all the continents of the world.
How did they get there? They did not appear in all these places at the same time. They would have started off in one place and spread out across the globe.
Palaeontologists suggest various mechanisms, such as dispersal, land bridges and vicariance. The picture is complicated by various factors including the timing of the break-up of Pangaea and the first recorded fossils of each dinosaur species. (Pangaea was the single continent which was believed to have broken up at the same time as the Cretaceous rocks were formed). Vicariance (or splitting of areas) is one explanation for the existence of the same type of dinosaurs on different continents which are widely separated today. For example, similar dinosaurs are found in South America and Africa. According to the vicariance model these continents were joined and the dinosaurs were living on what was to become South America and Africa. The timing of the break-up of Pangaea makes this one of the best explanations for fossil dinosaur distributions on these two continents.
Dispersal across the oceans on mats of floating vegetation has also been proposed. However, while this mechanism could work for small and medium sized animals it seems unlikely for large dinosaurs like, for example, the titanosaurs.
Transient land bridges have also been proposed to explain some of this distributions or fossil and living animals.
Young Earth creationist palaeontologists have also tried to explain the distribution of animals that we see today. Although they have not looked at the distribution of dinosaurs. The distribution of dinosaurs is difficult to explain if one holds to the most popular creationist geological models which suggest that most, if not all, Cretaceous rocks are flood rocks.
If Cretaceous rocks were deposited towards the end of the flood year, then dinosaurs must have been buried during the flood year. If we look at the dinosaur fossil record this seems unlikely. There are fossil dinosaur nests with eggs, some of which have been found to contain fully developed baby dinosaurs about to hatch out. There are many dinosaur footprints all over the world which show that the dinosaurs were walking around on various layers of Cretaceous rocks, which were subsequently covered by other layers of Cretaceous rocks. These processes take time, more time than is available at the end of the flood year. Also, it would have been impossible for dinosaurs to build a nest, lay eggs and incubate them, while the land was covered by the waters of the flood. There are also fossils showing the diversification of dinosaurs at this time, for example the trend to larger size, which would require hundreds of years at a minimum.
If the Cretaceous rocks were laid down after the flood, then the fossil dinosaurs are descendants of the dinosaur kinds which came off Noah’s ark. This model also involves the break-up of Pangaea many years after the flood (in the days of Peleg).
If this is the case then the answer to the question of why we find the same type of dinosaur on different continents could also be explained by one or all of the mechanisms of dispersal, land bridges and vicariance. Dispersal after the flood can also explain the diversification of dinosaur kinds after the flood.
As I research this subject, I will be posting about it in the new year, but as there is a massive amount of literature to read so it will be a slow process. Hopefully it will be worthwhile.
