Science Test: Rocks and Earth Structure

Comprehensive vocabulary flashcards covering Earth layers, tectonic plate boundaries, rock types (sedimentary, metamorphic, igneous), weathering mechanisms, the rock cycle, fossil formation, and specific rock specimens.

Crust

The solid outermost layer of the Earth, extending from $0\text{--}100\,\text{km}$ in depth.

Mantle

The semi-liquid layer of the Earth located between $100\,\text{km}$ and $2900\,\text{km}$ beneath the crust.

Outer Core

The liquid layer of the Earth's interior situated between $2900\,\text{km}$ and $5100\,\text{km}$ in depth.

Inner Core

The solid central layer of the Earth extending from $5100\,\text{km}$ to $6378\,\text{km}$.

Divergent Plate Boundary

A plate boundary where tectonic plates move apart from each other, creating landforms such as volcanoes, valleys, and canyons (e.g., Red Sea formation).

Transform Plate Boundary

A plate boundary where tectonic plates slide horizontally past one another, forming faults and causing earthquakes (e.g., Alpine Fault).

Convergent Plate Boundary

A plate boundary where tectonic plates collide or move toward one another, forming landforms such as volcanoes and mountains (e.g., Himalayas, The Alps).

Weathering (Rock Cycle)

The initial geological process of breaking rocks down into small pieces.

Erosion

The process by which rock sediments are carried away by water and wind.

Deposition

The stage in sedimentary rock formation where transported sediments are dropped on top of each other.

Compaction

The process in which accumulated sediment layers are pressed tightly together by overlying weight.

Cementation

The process in which dissolved minerals act as glue to bind compacted sediment particles together.

Sedimentary Rock

A category of rock formed through weathering, erosion, deposition, compaction, and cementation; characterized by layers, a grainy texture, a softer structure, and the potential presence of fossils (e.g., sandstone, chalk, limestone, shale, mudstone, coal).

Metamorphic Rock

A rock formed deep underground when an existing parent rock changes due to extreme heat and pressure; characterized as hard, dense, devoid of fossils, and potentially showing foliation or crystals (e.g., quartzite, slate, marble, gneiss, schist).

Foliation

Layering or banding observed in certain metamorphic rocks as a result of directed pressure.

Igneous Rock

A rock formed when molten lava or magma cools and crystallizes; typically hard, non-layered, often crystalline, and capable of displaying a glassy texture or vesicles.

Intrusive Igneous Rock

An igneous rock that cools slowly beneath the Earth's surface, allowing the growth of large crystals (e.g., granite).

Extrusive Igneous Rock

An igneous rock that cools rapidly on the Earth's surface, resulting in the formation of small crystals (e.g., basalt).

Vesicles

Small cavities or holes present in volcanic igneous rocks, formed by trapped gas bubbles during cooling.

Physical Weathering

A mechanical breakdown process that fractures rocks into smaller fragments without altering their chemical composition, akin to cracking or smashing a rock.

Freeze-Thaw

A mechanism of physical weathering in which water enters cracks in a rock, freezes, expands, and consequently widens the crack.

Chemical Weathering

The breakdown and alteration of a rock's internal minerals via chemical reactions, which causes the rock to soften, dissolve, or transform into new substances.

Acid Rain Weathering

A form of chemical weathering where rainwater containing dissolved carbon dioxide dissolves susceptible rocks such as limestone.

Biological Weathering

The disintegration of rocks caused by the activities of plants, animals, and microorganisms, such as plant roots wedging cracks apart or burrowing animals digging into rock crevices.

Limestone Weathering Equation

$CaCO_3 + H_2SO_4 \rightarrow CaSO_4 + H_2O + CO_2$, representing the reaction of calcium carbonate with sulfuric acid to yield calcium sulphate, water, and carbon dioxide.

Silica (in Fossilization)

The mineral compound that gradually replaces calcium phosphate in an organism's bones during the fossilization process.

Trace Fossils

A classification of fossils that record geological evidence of biological activity (such as footprints or burrows) rather than anatomical remains.

Mold Fossils

A type of fossil formed when an organism decays within sediment, leaving an impression or negative space of its shape in the surrounding rock.

Resin Fossils

Fossils formed when organisms are trapped and preserved inside ancient hardened tree sap or amber.

Body Fossils

Fossils consisting of preserved actual physical structures or skeletal remains of an organism.

Granite

A hard, intrusive igneous rock characterized by large crystalline grains.

Schist

A medium-grained metamorphic rock whose original precursor or parent rock is a protolith.

Sandstone

A grainy sedimentary rock composed of numerous accumulated layers of mineral or rock sediment.

Marble

A crystalline metamorphic rock produced when its parent rock, limestone, is subjected to heat and pressure.