| ICE AGES: - The impact of the ice ages and | | | | ecological history, and so dismissed them as |
| inter-glacial effects on the rise and fall of ocean | | | | unreliable. (9) Yet Broecker and his colleagues |
| levels and the earth readjustments to the | | | | disputed Emiliani's interpretation of the results. |
| departure of the ice cap cannot be over-looked in | | | | They could find no reason to suppose that key |
| the human historical picture. Research in the area | | | | sediment layers could have been lost in the |
| is far greater than in the recent past and we can | | | | manner suggested. As a consequence, they |
| learn what might have happened to earlier | | | | reinstated Emiliani's controversial findings as crucial |
| civilizations on earth. Atlantis is a given name for a | | | | evidence of a major shift in oceanic temperatures |
| civilization that inhabited many islands and coastal | | | | around 11,000 years ago. (10)Although Broecker |
| regions, in my mind. The idea of one central | | | | et al seemed keen to promote a date of c. 9000 |
| location makes little sense when one considers | | | | BC for the rapid transition from glacial to |
| such things as Ice Ages and changes in the flow | | | | post-glacial ages, there are indications that this |
| of the Gulf Stream and climate that resulted. | | | | event did not occur until a slightly later period. At |
| Because it lasted for from 30,000 to 100,000 | | | | least three lake sites in the Great Basin region |
| years and may have co-existed with other | | | | revealed carbon-14 dates around 8000 BC for a |
| civilizations rising and falling it is most inauspicious | | | | maximum water level shortly 'before' they |
| to debate one specific time when it was in Tara | | | | experienced a sudden desiccation after the |
| or Crete or the Azores or Bimini or even Finias. | | | | withdrawal of the ice sheets. (11) In addition to |
| That seems to be the usual debate among the | | | | this, marine shells from the St. Lawrence Valley, |
| over 25,000 books written about just this one | | | | which provided evidence of an invasion of |
| lost civilization. As long as people don't integrate all | | | | seawater coincident to a rapid ice retreat, |
| facts they inevitably just come up with theories | | | | frequently produced dates 'post' 9000 BC. |
| to fit pet or prevailing concepts. In Gateway to | | | | (12)Broecker and his colleagues accepted the |
| Atlantis, 'The Search for the source of a lost | | | | presence of these much lower dates and |
| Civilization' we see a far better scholar who is | | | | suggested that the whole matter was |
| doing the right kind of investigation. Mapping of the | | | | complicated by the fact that there had been an |
| ocean bottoms and geological understandings as | | | | estimated 200-year resurgence of glacial |
| well as studying glacial deposits and tree rings | | | | conditions, known as the Valders re-advance, |
| gives a better picture of history than history | | | | around the mid-ninth millenium BC. They therefore |
| books."In 1960 a scientific paper by Wallace S. | | | | acknowledged that their own findings might in fact |
| Broecker and his colleagues Maurice Ewing and | | | | relate to the recession of the ice fields after this |
| Bruce C. Heezen, of Lamont Geological | | | | time, bringing the dates of their suggested 'major |
| Observatory at Columbia University, Palisades, | | | | fluctuation in climate' and the 'sharp change in |
| New York, appeared in the 'American Journal of | | | | oceanic conditions' down to well below c. 9000 BC. |
| Science'. Entitled 'Evidence for an Abrupt Change | | | | (13)THE EVIDENCE OF POLLEN SPECTRAFurther |
| in Climate close to 11,000 years ago', it advanced | | | | evidence that dramatic changes accompanied the |
| the theory that a 'number of geographically | | | | transition from glacial to post-glacial ages came |
| isolated systems suggested that the warming of | | | | from the work of Herbert E. Wright Jnr, of the |
| world-wide climate which occurred at the close of | | | | School of Earth Sciences at the University of |
| Wisconsin glacial times was extremely abrupt. | | | | Minnesota, Minneapolis, (14) and J Gordon Ogden |
| (3)By examining sediment cores taken from | | | | III of the Department of Botany and Bacteriology |
| various deep-sea locations, Broecker and his team | | | | at the Ohio Wesleyan University, Delaware. (15) |
| were able to demonstrate that around c. 9000 | | | | Both examined the pollen spectra range from |
| BC. the surface water temperature of the | | | | sediment cores taken from various lake sites in |
| Atlantic Ocean increased by between six and ten | | | | the Great Lakes area and found they provided |
| degrees centigrade, (4) enough to alter its entire | | | | clear evidence of an abrupt shift in flora at the |
| ecosystem. More significantly, it was found that | | | | end of glaciation. The spruce forests that had |
| the bottom waters of the Cariaco Trench in the | | | | thrived in the cold harsh climate for many |
| Caribbean Sea, off Venezuela, suddenly stagnated, | | | | thousands of years were supplanted swiftly, first |
| {The Gulf Stream being sent back south from | | | | by pine and then by mixed hardwood forests, |
| hitting the land around the Azores when the | | | | such as birch and oak. Deciduous trees, as we |
| water level was lower suddenly started warming | | | | know, only thrive in a warmer climate.The |
| the Iceland and British Isles regions, again.} | | | | significance of these findings is the acceleration at |
| showing that an abrupt change in water circulation | | | | which this transition took place. In an article for |
| had taken place coincident to the warming of the | | | | the journal 'Quaternary Paleoecology' in 1967, |
| oceans. (5) Additionally, the silt deposits washing | | | | Ogden pointed out that some pollen spectra |
| into the Gulf of Mexico from the Mississippi Valley | | | | samples showed a 50 per cent replacement from |
| abruptly halted and were retained in the delta and | | | | spruce to pine occurring in just 10 centimetres of |
| valleys, as the waters from the glacier-bound | | | | sediment. (16) In one sample taken from a site |
| Great Lakes switched direction and began draining | | | | named Glacial Lake Aitken in Minnesota, the |
| through the previously frozen northern outlets. (6) | | | | transition from 55 per cent to 18 per cent spruce |
| With extreme rapidity, the water levels of these | | | | pollen occurred in only 7.6 centimetres of |
| lakes shrank from maximum volume, down to | | | | sediment, re- presenting a deposition |
| the much lower level they occupy today. | | | | corresponding to just 170 years. (17) The problem |
| (7)Among the data drawn on by Broecker and his | | | | here is that conventional geologists and |
| team to make their findings was the work | | | | paleoecologists consider that the transition from |
| conducted in 1957 by Cesare Emiliani of the | | | | glacial to post-glacial ages occurred over several |
| Department of Geology at the University of | | | | 'thousand' years, not just a few hundred {The |
| Miami. He found that deep-sea cores displayed | | | | time it takes for one or two trees to live and |
| clear evidence of an abrupt temperature turn | | | | die.} years.These findings so baffled Ogden that |
| around in 9000 BC. was responsible for the other | | | | he was led to comment: 'The only mechanism |
| changes set out by Broecker et al. (8) However, | | | | sufficient to produce a change of the kind |
| since other cores examined by Emiliani had not | | | | described here would therefore appear to be a |
| shown the same rapid transition, he decided that | | | | rapid and dramatic change in temperature and/or |
| the anomalous cores lacked vital sediment layers | | | | precipitation approximately 10,000 years ago. |
| covering a period of several thousand years of | | | | |