The shift from the golden safe hall of Progenitor Vault Three to the lower mantle rift was an abrupt plunge back into deep-rock violence. Four hours of healing medicine sleep and high-calorie rations had rejuvenated the squad. But they stood at the threshold of the southern crust-sink chimney pipe. Then, the sense tracking data was daunting.
The tunnel leading to Progenitor Vault Two was not a wide, navigable magma canal. It was a jagged, upright fault fracture plunging through the deepest strata of the Earth’s upper mantle. He dropped from minus nineteen thousand meters to minus twenty-two thousand four hundred meters.
The physical behavior of matter under five gigapascals of lithostatic pressure was unlike anything met in surface geology. At this depth, the boundary between solid and liquid dissolved. The metamorphic dense green rock didn’t fracture when struck. It flowed under sideways tearing force, re-crystallizing in real-time along aimed stress lines.
Arthur kept his hand pressed against the rock wall as they dropped. He felt the rhythmic, pulsing warmth of the planet’s mantle. Through his test monocle, he could see the complex lattice of olivine crystals shifting and reorganizing under the huge pressure, venting micro-streams of spark-charged gas that shone like green neon along the fault lines.
