The Davy Chain
Figure 131
Figure 131 geologic map of the Davy area

 Larger NASA version of above
.

Legend of the geologic map of the Davy area
Dashed lines - dashed where inferred,queried where doubtful
This is a reduced version of part of a geologic map of the Davy area compiled by R. Hereford of the U.S. Geological Survey. Photogeologic mapping did not provide an unambiguous answer to the question of the origin of the Davy chain, but did provide much information on the succession of events that shaped this part of the Moon's surface. Following the map explanation, the succession is briefly as follows: (1) An early period of intense cratering during which the large crater Davy Y was excavated and its rim uplifted. (2) A presumably brief period during which the Cayley Formation and one other plains unit were deposited. (The origin of the Cayley as a semifluid cloud of ejecta from the Imbrium basin was discussed in figs. 46, 54, and 55.) (3) A long period when scattered medium-sized craters and their deposits were formed. (4) The formation of the Davy crater chain and the larger, presumably volcanic, craters Davy G and Davy GA. (5) Finally, mass movement of material on steep slopes to form relatively fresh slope deposits and sporadic impact by very small bodies that made craters too small to be shown at the scale of the map.-G.W.C.

 

Dashed where inferred, queried where doubtful

 

A line - trough line marks axis
Trough 

Line marks axis

 

Curved line - crater rim crest
Crater rim crest

 

Semi-curved line - chain crater rim crest
Chain crater rim crest

 

Elliptical circle - depression
Depression

 

Report Source: NASA SP-362, Page 134, Figure 131

This web page was created by Francis Ridge for The Lunascan Project
   Section Directory 43
Home Page