Structural geology

• What does structural geology focus on?; Folds faults and other deformation structures in the lithosphere.
• How are columnar joints formed?; From the cooling of molten materials typically part of the ophiolite sequence.
• What causes the vertical orientation of columnar joints?; The cooling process happening from the top down resulting in the formation of vertical columns as the lava solidifies.
• What causes folds to form in rocks?; Tectonic forces typically compression causing deformation.
• What are anticlines and synclines?; Anticlines are upward-arching folds (v or u shape) with the oldest rock in the center while synclines are downward-arching folds (inverted u or v shape) with the youngest rock in the center.
• What is a normal fault?; A type of fault where the hanging wall moves downward relative to the footwall caused by tensional forces pulling rocks apart.
• How are veins in rocks formed?; When mineral-rich fluids flow through fractures and precipitate forming cracks in the rock.
• How do igneous intrusions form in strata?; When molten rock (magma) rises from beneath the Earth's surface and intrudes into existing layers of sedimentary rock cooling and solidifying to form igneous rock bodies.
• What did early civilizations marvel at in terms of the Earth's features?; The enormity of mountains and oceans created by supernatural processes.
• What was the belief of early civilizations regarding the Earth's features?; Gods and monsters contorted the Earth and caused natural phenomena like flaming rock and ground-shaking creatures.
• What characterized the intellectual renaissance in the 15th century?; It was the age of discovery and the birth of the scientific method.
• Who was a prominent figure during the intellectual renaissance?; Leonardo da Vinci (1452-1519).
• Who is credited with the first description of rock deformation in the 17th century?; Nicholas Steno (1631 - 1686).
• What did James Hutton establish which is viewed as the birth of structural geology?; The Principle of Original Horizontality.
• What concept did James Hutton propose in his 'Theory of the Earth with Proofs and Illustrations'?; The concept of uniformitarianism.
• Who formulated the Continental Drift Theory?; Alfred Wegener (1880 - 1930).
• Who formulated the Mantle Convection Theory?; Arthur Holmes (1898 - 1965).
• Who proposed the Seafloor Spreading Hypothesis?; Harry Hess (1906 - 1969).
• What is the Plate Tectonics Theory?; The Earth consists of several rigid plates that change in space and time offering a unifying explanation for various geologic phenomena.
• What are some examples of geometric features in rock that can be described?; Planar (or sub-planar) surface curviplanar surface linear feature.
• What are some classes of structures included in the basic classification scheme based on geometry?; Joint vein fault fold shear zone foliation lineation.
• What are the primary classifications based on geologic significance?; Local gravity-driven local density-inversion driven fluid-pressure driven tectonic.
• What is the classification based on the timing of formation?; Syn-formational penecontemporaneous post-formational.
• What is the classification based on the process of formation or the deformation mechanism?; Fracturing frictional sliding plasticity diffusion.
• What are the classifications based on the mesoscopic cohesiveness during deformation?; Brittle ductile brittle/ductile.
• What is the classification based on the strain significance?; Contractional extensional.
• What is strike-slip related to?; Movement without shortening or extension.
• What is continuous structure?; Occurs through the rock body at all scales.
• What is penetrative structure?; Occurs throughout the rock body at the scale of observation with spaces between the structures up close.
• What is localized structure?; Continuous or penetrative structure occurs only within a definable region.
• What is discrete structure?; Structure occurs as an isolated feature.
• What does micro-scale refer to?; Features that are visible optically at the scale of thin sections or that may only be evident with the electron microscope.
• What does meso-scale refer to?; Features that are visible in a rock outcrop but cannot necessarily be traced from outcrop to outcrop.
• What does macro-scale refer to?; Features that can be traced over a region encompassing several outcrops to whole mountain ranges.
• What does mega-scale refer to?; Refers to continental-scale deformational such as the movements of tectonic plates over time.
• What is the Law of Original Horizontality?; Strata are deposited horizontally making bedding an internal reference frame.
• What is the Law of Superposition?; Strata follow one another in chronological but not necessarily continuous order.
• What do separated but aligned outcrops of the same lithologic sequence imply?; Stratigraphic continuity.
• What are sharp discontinuities in lithologic patterns?; Faults unconformities or intrusive contacts.
• What are consistent structural attitudes within deformed areas called?; Structural domains.