Depth 55.6 meters; Drill Hole 79-1; erupted 1959, sampled, 1979. Deep within the lake the lava was 31 percent liquid (now brown glass) in 1979. Notice that the black iron-titanium oxide minerals visible in the other drill core photos had not yet started to crystalize.
At spreading ridges on the sea floor, new basaltic material wells up in cracks through earlier solid basalt. This glassy basaltic dike was injected into solid basalt, shouldering it aside and forcing the two tectonic plates to move apart. Hole 504B: 111-504B-142R-01A. 9-17 cm, #1B
Mare basalts from the Imbrium Basin range from 3.2 to 3.4 billion years in age, showing that volcanism in the basin lasted over 200 million years. This specimen formed midway through the epoch. Collected by Apollo 15.
Toothpaste squeezed from a giant tube? No, this is a pillow of basalt, the most common lava erupted on the sea floor. Its thin coating of dark manganese oxide minerals was precipitated from hot mineral-rich water, perhaps with the aid of bacteria.