Which contains more thermal energy: an ice cube or an iceberg?

I think it is the iceberg boss.

If an iceberg is the same temperature on the outside as it is on the inside then it becomes water, just like an ice cube. Imagine if you made a huge ice cube and you core drilled it, it’s insides would be colder than it’s outsides. An iceberg is simply an extension of that. One could think of it as a thermal capacitor, or a huge cooler pac. An iceberg is a piece of a glacier which was formed by ancient snow. The weight of years of snow fuses the snow into ice. Gravity has moved it downhill until it was at the edge of ocean and cracked off under it’s own weight. Included along with ice, atmospheric dust, are many tiny air bubbles trapped when the snow fell.