(LAC-24) Geologic map of the Sinus Iridum quadrangle of the moon
The Sinus I ridum quadrangle includes the northwestern sector of Mare I mbrium , the Sinus I ridu m embayment, the arcuate Montes Jura which partly surround Sinus I ridum , and several terra islands in the mare such as the Montes Teneriffe , Montes recti, and C. Herschel * . Mare imbrium occupies a c omple x depression or basin consisting of an inner basin and several outer concentric troughs separated by raised rings ( H artmann and Kuiper, 1962). The center and much of the inner basin , p art of the first raised ring, and part of the first trough lies within the quadrangle. The terra islands are exposed parts of the first r aised ring, which is approximately 670 km in diam eter. Sinus Iridum embays a simpler and smaller structure, a crater 250 km in diameter (herein referred to as the Iridum crater) whose partly exposed rim crest is the Montes Jura. Mare ridges overlie buried parts of the Imbrium ring and the Iridum crater rimcrest (fig. 1).