How old is the oldest known rock in the Mount Desert Region. Think back to the rock cycle. What type of rock is this?

An analysis of The Mount Desert Region’s oldest rock:

Maine’s Mount Desert Region is home to some the most ancient rocks dating back approximately 420 million years. The Acadian Orogeny is a geological phenomenon that created the Appalachian Mountains as well as the rock formations in the area. A granite intrusion, which has been dated to 420 million year old by Wadman 2019, is the oldest rock found in this region. This rock is an intrusive type of igneous rock. It was formed by molten magnesium from deep in the Earth cooling and solidifying (American Geosciences Institute 2021). These rocks, known as intrusive igneous, are among the oldest on Earth. This rock is therefore the oldest in the Mount Desert Region. This discovery has enormous implications. It provides an insight into the past that allows us to better understand the evolution of the area and its geology over the hundreds of millions years. Additionally, geologists can use the rock’s age as a reference point to understand the age and composition of other rocks in this region. This allows them to correctly date and interpret their geology. This rock also provides an opportunity for geologists to investigate the process of forming the Appalachian Mountains.