試題詳解

2. Based on global observations, the ocean floor at age of 60 Ma is 5 km decp. For older ocean floor of 120 Ma, the depth of the floor is expected to be__________ ? According to the instantaneous half-space cooling model and isostatic compensation, the "predicted" depth for such 120-Ma-old ocean floor is more likely be__________ ? Choose the closest answer from below:
(A) 5 km unchanged；
(B) slightly deeper as 5.5 km；
(C) approaching to 7 km；
(D) doubled to 10 km. (5 pts each, 10 pts total)