Geology: Pseudomorphic vs Allomorphic Replacement and Bioturbation

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What type of rock is typically formed when magma cools at the mid-ocean ridge?

Granite

Basalt (correct)

Sedimentary

Obsidian

At what temperature does magnetite lose its magnetism?

500°C (correct)

200°C

600°C

400°C

What is the phenomena called when magnetite becomes magnetic again upon cooling?

Curie conversion

Thermal magnetization

Magnetic revival

Remanent magnetism (correct)

What process describes the large scale motions of Earth's lithosphere?

Plate Tectonics Signup and view all the answers

Which layer of Earth's interior can flow like a liquid on geological time scales?

Asthenosphere Signup and view all the answers

Which term describes the process where an old grain is replaced with a new mineral while retaining the relict crystal form?

Pseudomorphic Signup and view all the answers

What is the main difference between pseudomorphic and allomorphic replacements?

Crystal form is retained in pseudomorphic but not in allomorphic replacements Signup and view all the answers

What is the term for the physical and biological activities that occur at or near the sediment surface causing mixing of sediment?

Bioturbation Signup and view all the answers

Which diagenetic process involves compaction, slumping, and infiltration?

Slumping Signup and view all the answers

What type of processes such as cementation, authigenesis, and recrystallization reduce porosity and permeability in sediments?

Physiochemical processes Signup and view all the answers

What process reduces porosity in sedimentary rocks by filling in the pore spaces between grains?

Cementation Signup and view all the answers

Which of the following minerals is NOT mentioned as a common cement in sedimentary rocks?

Halite Signup and view all the answers

What is the term for the process in which new mineral phases crystallize in sediment or rock during diagenesis?

Authigenesis Signup and view all the answers

In replacement, which type involves the new mineral being the same phase as the old one or a polymorph of it?

Neomorphic Signup and view all the answers

What happens to unstable constituents as fluids pass through sediment?

They dissolve and are transported away or reprecipitated in nearby pores Signup and view all the answers

What term describes the process in which the volume of a sediment is reduced as the grains are squeezed together?

Compaction Signup and view all the answers

Which of the following processes involves inducing a reorientation of the crystal lattices of mineral grains?

Recrystallization Signup and view all the answers

Under what conditions does recrystallization in sediment occur?

Pressure and temperature changes Signup and view all the answers

Which diagenetic process involves dissolving a mineral?

Solution Signup and view all the answers

What factor controls the degree of compaction in sediments?

Grain shape and sorting Signup and view all the answers

What is the major diagenetic process that contributes to creating secondary porosity in rocks?

Interstratal solution Signup and view all the answers

Which of the following factors controls the degree to which diagenetic processes contribute to sedimentary rock formation?

Composition pressure due to burial Signup and view all the answers

Which type of rock is formed from metamorphosis due to intense heat and pressure beneath the Earth's surface?

Metamorphic Signup and view all the answers

What type of rock is likely to have ribbonlike layers and shiny crystals on its surface?

Gneiss Signup and view all the answers

Which type of rock is formed when molten rock cools and hardens?

Igneous Signup and view all the answers