The more you lose, the more open water is created, the more warming goes on in that open water during the summer, the less ice forms in the winter, the more melt there is the following summer.
Continued bombardments and internal pressures made the growing Earth hotter, causing its interior to melt and the heavier elements to sink and form Earth's core.
Evidence that an ice-free corridor between two ice sheets developed when the continental ice first began to melt came primarily from radiocarbon dating.
The conditioned response, once it is firmly established, can be extinguished dozens of times, but it sill always return, like the proverbial bad penny.
In this case, Uranium-Lead Dating was used to establish that half of the sandstone in the samples was formed at the same time the granite in the Appalachian Mountains was formed.