It was the Precambrian time period.
Precambrian eon4567.17-542 million years agoMesozoic era251-65.5million years agoSo precambrian came first...........
The Precambrian is a long period and just as Earth has many climates now, it had many then.
Old, cool igneous rock sinks.
a metamorphic rock
The word Precambrian describes the approximate age of the rock, it could be sedimentary, igneous or metamorphic and there are many ways in which these 3 types of rock could form.
The Rock of Precambrian shield formed about 4 billion years ago during the Precambrian period. It is one of the oldest geological formations on Earth, characterized by its ancient rocks and lack of fossils.
Precambrian rocks are typically very old, dating back over 600 million years. They often contain minerals like quartz, feldspar, and mica due to their formation process in the early Earth's crust.
Precambrian.
correlation between rock units is impossible
The term "Precambrian" refers to the eon of geological time that predates the Cambrian period, which marks the beginning of abundant fossils in the rock record. It encompasses a vast span of time, roughly from the formation of Earth (about 4.6 billion years ago) to 541 million years ago.
Old age. You were likely to die from it, back then.
The Precambrian rock record suggests that Earth's early history was characterized by the formation of continental crust, the evolution of life from simple bacteria to complex organisms, and dramatic changes in the environment due to volcanic activity and the shaping of the planet's surface.
are severely bent and folded
Igneous rocks can be found in the mountains, which are partially composed of Precambrian plutonic rock.
Most of our knowledge of Precambrian rocks comes from studying exposed rock outcrops on the Earth's surface, as well as from drilling deep boreholes and mining operations. Additionally, information about Precambrian rocks can be gleaned from geophysical surveys and satellite imagery.
The Canadian Shield is known as the Precambrian Shield because it is made up of some of the oldest rock formations on Earth, dating back to the Precambrian Eon. These rocks were largely formed between 4.6 billion to 540 million years ago, before the Paleozoic era began.