| From: Greg Mc | 30/12/99
1:20:27 |
| Subject: Yonaguni Underwater Structures | post id:
21957 |
| Hi folks, are there any
Geologists out there who have had a look at pics of these
structures? I'm tempted to dismiss them as natural formations but if not, WOW! There are some staircases too. | |
| From: Greg Mc | 30/12/99
1:31:34 |
| Subject: re: Yonaguni Underwater Structures | post id:
21961 |
| Yeah, they definately
exist. Some Japanese friends of mine scuba dived on them a few months ago but whether they are man made or not is the issue. | |
| From: Alan™ | 30/12/99
1:32:12 |
| Subject: re: Yonaguni Underwater Structures | post id:
21962 |
| The 3 pictures on the page you
put up could be man made or natural. I can't really tell that much without
knowing the types of rocks involved and seeing more pictures. Horizontal
layering like that is fairly common. Maybe Kevin can shed a bit more light
on the subject. | |
| From: Matt | 30/12/99
1:34:02 |
| Subject: re: Yonaguni Underwater Structures | post id:
21963 |
| They look man made - how accurate
is the dating of these things - I guess as good as any land based dating.
What do they use to date such things? | |
| From: kelvin fox | 30/12/99
2:27:50 |
| Subject: re: Yonaguni Underwater Structures | post id:
22000 |
| Hi There Lets first discuss the dating of things; Normal sedimentary stratigraphy is normaly dated via the fossil record. Other things without fossils can be dated a number of chemical ways eg U/Pb isotope dating. The problem with dating man made rock strtuctures is you get the age of the rock not the age of the structure (a similar problem is encountered with dating caves-you get the age of the limestone not the cave). The only real way of dating the structures would be by other artifacts, comparisons to similar already dated structures or writings on the walls etc. Secondly you get similar structures in nature via jointing. the scale on the photos (relative to the divers) is within the scale of natural features. One of my first year uni textbooks has a picture of similar features at that scale at the American Niagra Falls. Thirdly (I am no Archeologist) I believe that things like the pyramids are build of hand carved blocks. At the size of these structures there would be many blocks that make up the structures. These would not be resolvable at the photo scale but the dudes doing the study on them would look for these features. Unless there are parts of the structures missing they seem to end on their top surfaces at large flat plains-most things like Mayan or Egyptian pyramids have apexes. There are no apexes visible (they may have photographed apexes and not shown the photos but this is unlikely). Therefore I am leaning towards the geological cause of these structures (I am willing to change my attitude if more archeological evidence comes along). The orientation means nothing really. i have measured things with east-west or north-south strikes (bearing directions) lots of times in the field. The real convincing evidence for man made features would be if there were lots of them in the same orientation but the strtike of geological features in the region (such as faults) varied away from this orientation. i have now muddied the clear japenese waters kelvin | |
| From: kelvin fox | 30/12/99
23:43:11 |
| Subject: re: Yonaguni Underwater Structures | post id:
22177 |
| Hi there i am making my observations from photos and a couple of text pages. There is a lot more data available that I haven't access to and this data probably opens the pandoras box. The alternate answer is their regularity and step like nature. People associate these features with man made features not nature and being underwater makes them more mysterious. At the end of the day geology is not as interesting or imaginative as early civilizations especially combimed with the possibility of extra terrestrial involvement. kelvin | |
| From: Matt | 30/12/99
23:48:24 |
| Subject: re: Yonaguni Underwater Structures | post id:
22179 |
| True - but I would find geology
still a very interesting answer (if it is "only" that) - how would you get
such rigid steps underwater - some weird water currents??
| |
| From: kelvin fox | 31/12/99
0:14:15 |
| Subject: re: Yonaguni Underwater Structures | post id:
22188 |
| Hi There The original geological structure was not formed underwater. Rocks derive the majority of their features from the following sources Sediments-from the rivers deltas glaciers etc that they were formed from eg layering of stratigraphy volcanic rocks-from the volcanic source eg lava flows, lava tunnels, ash flow features intrusive rocks-eg granites from the way the liquid that the rocks from solidified slowly over millions of years deep in the crust. Superimposed on all of these types of things are the metamorphic and structural features such as folds faults bends warps and joints These come about when surficial rocks are buried in the deep crust either by large amounts of sedimentation covering them or by subduction pushing them into the crust, or when buried rocks are thrust to the surface eg the some of the rocks in the Himalayas are ancient sea floor rocks that have been thrust over each other to form the mountains (the process is called obduction). As buried rocks are slowly exposed over millions of years and the top surfaces are eroded the weight of material obviously decreases. As the pressuse is released 'relaxation' cracks appear (normally 2 sets at 90 degrees to each other). These relaxation cracks are called joints and are responsible for the step like appearance. they are therefore surface or near surface featue of the rocks. being near coastal it only takes a small change in sea level to either expose or flood features (depending on expansion or contraction of the ice sheets in the Arctic and Antarctic regions). Geological history is littered with these events. the last major change in sea level I believe occurred only about 10 000 years ago. More mud for the japenese waters. kelvin | |
| From: Alan™ | 31/12/99
0:36:26 |
| Subject: re: Yonaguni Underwater Structures | post id:
22210 |
| Kevin Would I be guessing in the right direction in saying the rocks shown in the photos would be likely to be a slate or something based upon a metamorphic form of mudstone. Even though the do look fairly thick. | |
| From: kelvin fox | 31/12/99
1:01:32 |
| Subject: re: Yonaguni Underwater Structures | post id:
22222 |
| hi there Impossible to tell. The slaty looking cleavage is found in other rocks as well. No guesses this time Kelvin | |