Earth from Space - Image Information


LOCATION Direction Photo #: ISS020-E-26195 Date: Jul. 2009
Geographic Region: CHAD
Feature: AOROUNGA IMPACT CRATER,YARDANGS


IMAGE
 
Aorounga Impact Crater, Chad

Aorounga Impact Crater is located in the Sahara Desert, in north-central Chad, and is one of the best preserved impact structures in the world. The crater is thought to be middle or upper Devonian to lower Mississippian (approximately 345-370 million years old) based on the age of the sedimentary rocks deformed by the impact. Spaceborne Imaging Radar (SIR) data collected in 1994 suggests that Aorounga is one of a set of three craters formed by the same impact event. The other two suggested impact structures are buried by sand deposits.

The concentric ring structure of the Aorounga crater--renamed Aorounga South in the multiple-crater interpretation of SIR data--is clearly visible in this detailed astronaut photograph. The central highland, or peak, of the crater is surrounded by a small sand-filled trough; this in turn is surrounded by a larger circular trough. Linear rock ridges alternating with light orange sand deposits cross the image from upper left to lower right; these are called yardangs by geomorphologists. Yardangs form by wind erosion of exposed rock layers in a unidirectional wind field. The wind blows from the northeast at Aorounga, and sand dunes formed between the yardangs are actively migrating to the southwest.


Images: All Available Images Low-Resolution 272k
Mission: ISS020  
Roll - Frame: E - 26195
Geographical Name: CHAD  
Features: AOROUNGA IMPACT CRATER,YARDANGS  
Center Lat x Lon: 19.1N x 19.2E
Film Exposure:   N=Normal exposure, U=Under exposed, O=Over exposed, F=out of Focus
Percentage of Cloud Cover-CLDP: 10
 
Camera:: N3
 
Camera Tilt: 42   LO=Low Oblique, HO=High Oblique, NV=Near Vertical
Camera Focal Length: 800  
 
Nadir to Photo Center Direction: SW   The direction from the nadir to the center point, N=North, S=South, E=East, W=West
Stereo?:   Y=Yes there is an adjacent picture of the same area, N=No there isn't
Orbit Number: 1198  
 
Date: 20090725   YYYYMMDD
Time: 105733   GMT HHMMSS
Nadir Lat: 21.5N  
Latitude of suborbital point of spacecraft
Nadir Lon: 20.7E  
Longitude of suborbital point of spacecraft
Sun Azimuth: 242   Clockwise angle in degrees from north to the sun measured at the nadir point
Space Craft Altitude: 187   nautical miles
Sun Elevation: 86   Angle in degrees between the horizon and the sun, measured at the nadir point
Land Views: CRATER, DESERT, EROSION  
Water Views:  
Atmosphere Views:  
Man Made Views:  
City Views:  

Photo is not associated with any sequences


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