Introduction to Geology: Earth's Structure, Plate Tectonics, and Geological Time

What is geology?

The study of Earth.

Why do geologists study Earth?

Out of curiosity and for practical reasons such as understanding life evolution, searching for resources, and assessing geological risks.

What do geologists do?

They work in resource industries, protect natural resources, minimize geological risks, conduct research, and teach.

What are minerals?

Naturally occurring, specific combinations of elements with particular three-dimensional structures.

What are rocks?

Mixtures of minerals that can form through igneous, sedimentary, or metamorphic processes.

What drives tectonic plates?

Mantle convection caused by heat from the Earth's core.

How old is the Earth?

Approximately 4.57 billion years.

What is a hypothesis?

A testable, educated prediction about what will happen in an experiment.

What is a mineral?

A pure substance with a specific composition and structure, naturally occurring, inorganic solid.

What is magma?

Cooling of molten rock.

What are the three rock groups?

Igneous, sedimentary, and metamorphic.

What is the difference between a mineral and a rock?

A mineral is a pure substance with a specific composition, while a rock is typically a mixture of several minerals.

What are the major components of Earth's internal structure?

Core (iron), outer core (liquid iron), inner core (solid iron), mantle (iron and magnesium silicate minerals), and crust (granite and basalt).

What is the main component of Earth's core?

Iron (Fe).

What is the geothermal gradient?

The rate of increase of temperature with depth in the Earth, typically around 30˚ C/km within the crust.

What is halite?

A halide mineral composed of sodium (Na) and chlorine (Cl), also known as table salt.

What is the lithosphere?

The rigid outer part of the Earth, including the crust and the upper mantle.

What is mantle convection?

The process of heat transfer from the core to the mantle, causing slow circulation of mantle material.

What are divergent plate boundaries?

Regions where tectonic plates move apart, allowing magma to rise and create new crust.

What is the significance of geological time?

It helps understand the evolution of Earth and the processes that shape it over billions of years.

What is the difference between the Hadean and Phanerozoic eons?

Hadean is the first eon (4.57 to 3.80 Ga), while Phanerozoic is the most recent eon encompassing the Paleozoic, Mesozoic, and Cenozoic.

What is the role of geologists in society?

They reduce risks from geological hazards, discover resources, and study climate change.

What is the process of subduction?

When part of a tectonic plate is forced beneath another plate along a subduction zone.

What is basalt?

A volcanic rock of mafic composition.

What is granite?

A felsic intrusive igneous rock.

What is schist?

A metamorphic rock with visible aligned mica crystals.

What is sandstone?

A rock primarily comprised of sand-sized particles.

What is a tectonic plate?

A region of the lithosphere that moves across the Earth's surface.

What is the significance of paleontology in geology?

It requires an understanding of biology and helps in studying the evolution of life.

What proportion of geological time did dinosaurs exist?

3.3% of geological time.

How thick could sedimentary rock accumulate over 30 million years at a rate of 1 mm/year?

30,000 metres or 30 kilometres.