Google
Official Google Earth Download Site

Google Earth Community
You are not logged in. [Login] Entrance · Main Index · Search · Active Topics
New user · Who's Online · FAQ · KML Reference · GE Guide

Earth Moderated >> Nature and Geography (Moderated)
Previous topic Previous   View all topics Index   Next topic Next   Threaded Mode Threaded  

Jump to first unread post. Pages: 1 | 2 | (show all)
cptpies
Tourist


Reged: 08/03/05
Posts: 201
Loc: Crawley ,UK
Re: Is this a crater? [Re: DamOun]
      #770704 - 01/26/07 02:00 AM

According to the geological map of Yemen this feature is in Tertiary sediments which are geologically quite young, 50 - 60 Ma. If it was an impact crater it would have to be much much younger than this to remain visible and influence local drainage. It therefore should still retain some of the distinctive features such as a central uplift and uplifted sediments at the edge, which I'm not seeing. the beds here are very flat lying or maybe slightly folded which would explain the curved appearance of the orange brown outcrop of more erosionally resistive rock on the eastern side. The apparent curve of the Western side is just a fluke of the drainage pattern. if you ignore the Eastern half of the feature the Western half doesn't look circular at all.

I'm sorry chaps but I'm of the opinion that this is a red herring.

Post Extras: Print Post   Remind Me!   Report this Post  
Cintos
Tourist


Reged: 01/27/06
Posts: 57
Loc: Connecticut, USA
Re: Is this a crater? [Re: cptpies]
      #771580 - 01/26/07 03:14 PM

cptpies notes, with some strong arguments, that:

Quote:

I'm sorry chaps but I'm of the opinion that this is a red herring.



I must ask, cptpies: have you looked at the 1990 EarthSat image from Terraserver.com?. I provided?

From any angle and any distance from the CRT, there is an impresssive circle jumping out of the image. This is just as proounced in a 1999 15 meter resolution image that is only availabel to subscribers.

--------------------
"Don't use quotations. 
     ... Tell me what you know." -Ralph Waldo Emerson

Post Extras: Print Post   Remind Me!   Report this Post  
cptpies
Tourist


Reged: 08/03/05
Posts: 201
Loc: Crawley ,UK
Re: Is this a crater? [Re: Cintos]
      #775026 - 01/29/07 04:58 AM

Hadn't seen that Cintos. I must say that's a little bit more convincing. It suggests an almost completely eroded crater defined mainly by mineralisation of the geology. The drainage is still basically unaffected by its presence apart from the central basin.

Post Extras: Print Post   Remind Me!   Report this Post  
DamOun
Tourist


Reged: 11/08/05
Posts: 25
Re: Is this a crater? [Re: cptpies]
      #777439 - 01/31/07 01:26 AM

cptpies,

Yes indeed the crater is Post Tertiary. By the way have you managed to review the area with Terrain Layer "on" on GE? Definitely you would notice the eroded ridges on western side as well. The only reason for soft erosion pattern on western side is due to relatively soft formation (shales and claystone beds).

I am unable to find any regional fold on eastern side to confirm the "fold theory" rather I do notice a slight depression of brown beds (with its curvature slightly dipping into the crater) with the radius going WSW - almost in the center of the crater.

The bending of hard beds (of east) on the edges near streams are usually due to erosion of softer material beneath the hard rocks.

Further please observe the radial drainage pattern by just ignoring the main regional drainage system for time being. To me the drainage pattern should be corresponding with features on which they are been generated .

The case seems to be of heavy erosion of the crater due to regional uplift as indicated by the deep incision caused by the drainage (it can be confirmed from the drainage feature on the regional level).

To me if lets suppose the age of the crater is 10 Ma there is still pretty much chance for most of its feature to be eroded away due to heavy erosion.

To me this topic is still debatable

--------------------
B3st R3Gards
DamOun~

Post Extras: Print Post   Remind Me!   Report this Post  
Pages: 1 | 2 | (show all)


Previous topic Previous   View all topics Index   Next topic Next   Threaded Mode Threaded  


Extra information
0 registered and 2 anonymous users are browsing this forum.

Moderator:  esterrett, Jumble, Kempster, Hill, mcshea98, dulce, jeffryv, Frank_McVey, NormB, Cyclonic, tekgergedan, no_stranger, LuciaM, BeadieJay, TheLedge, Noisette, danescombe, Michal_Drewniak, freezer_magnet, mutex, marinerfan, Delta102, bebop 

Print Topic

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Topic views: 4032

Rate this topic

Jump to

earth.google.com    bbs.keyhole.com

*
UBB.threads™ 6.5.1.1