Mariana Trench: The deepest depths

Mar 4, 2020
Why is the water so cold? The cradles that hold the oceans are much warmer. Both the internal heat and the surface heat should make a beeline to that cold water. Wouldn't that deep water be continuously absorbing earth's internal heat? The water down in boreholes is super heated. What is continuously cooling all that deep ocean water? It's quite a heat sink. If the planet can sink heat there, maybe we can.