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✳️Cinnabar is a toxic mercury sulfide mineral with a chemical composition of HgS. 🔷It is the only important ore of mercury. It has a bright red color that has caused people to use it as a pigment, and carve it into jewelry and ornaments for thousands of years in many parts of the world. Its […]
🔷Kimberlites, named after the town of Kimberly, South Africa, where they were first described, are volcanic rocks that originate in Earth’s mantle.🔷They are mined exclusively for diamonds. The photo shows the “Big Hole” at Kimberly.🔷The Hole was mined from 1871 to 1914 and reached a depth of 240 m below the surface. Subsequently it filled […]
Geological Time Scale The geological time scale is a system of chronological measurement that relates geological events and geological time to a numerical scale. It is used to describe the timing and relationships between events that have occurred throughout Earth’s history. The time scale is divided into four main parts: Eons, Eras, Periods, and Epochs. […] Table of Contents Toggle Geological Time Scale
What are Rare Earths? The Japanese call them “the seeds of technology.” The US Department of Energy calls them “technology metals.” They make possible the high tech world we live in today – everything from the miniaturization of electronics, to the enabling of green energy and medical technologies, to supporting a myriad of essential telecommunications and defense systems. […] Table of Contents Toggle What are Rare Earths?Which Elements ...
Geology 101 is the study of the Earth and its materials, structures, processes, and history. It is a broad field that encompasses many different disciplines, including mineralogy, petrology, paleontology, and geophysics. Geologists study the Earth’s physical features, including its rocks, minerals, soils, and water. They also study the Earth’s internal structure and the processes that […] Table of Contents Toggle Why Study Geology?What Do GEOSCIENTISTS ...
What is Volcano I heard about the volcano before 🤔??….We all see volcanoes in movies and news, but did you ask yourself why or how do they happen? On our trip today, we will explore the volcano and see its formation, why it happens, and how.. Are you ready, hero ??Let’s start our journey The […] Table of Contents Toggle What is VolcanoOne ...
An unconformity is a surface of erosion or non-deposition that separates two rock units that have different ages. It represents a time gap in the geologic record, and it occurs when sedimentary rocks are tilted, uplifted, and eroded before new sediment is deposited on top of them. There are three types of unconformities: Disconformities A […] Table of Contents Toggle There are three types of unconformities:
Minerals are homogeneous, naturally occurring, inorganic solids that have a definite crystalline structure and chemical composition. In 1995, the World Minerals Organization put another definition saying that “a mineral is an element or a chemical compound that is naturally crystalline and formed as a result of geological processes.”Minerals have their own specific physical properties which […] Table of Contents Toggle Minerals are classified according to their chemical composition.
The difference between mineral, metal and ores Many people confuse three completely different classes of substances (minerals, ores, and metals), so that metal becomes a mineral, and all minerals become ores. Minerals Minerals are inorganic solids (elements or compounds) that have distinct physical properties. Each substance has a known atomic structure and a fixed chemical […] Table of Contents Toggle MineralsOres materialsMetals
Geology online Quizzes questions and answers. Free online quiz with multiple-choice questions (MCQ) without registration. Geology Multiple Choice Questions geology questions and answers | geology questions for competitive exams | geology exam questions. Geology quiz questions and answers.geology quizes. Geology online quiz.
In geology, "trend" and "plunge" are terms used to describe the orientation of linear geological features, such as fold axes, mineral veins, or lineations. They are crucial for understanding the spatial orientation and behavior of these features in three-dimensional space. Trend Definition: The trenRead more
In geology, “trend” and “plunge” are terms used to describe the orientation of linear geological features, such as fold axes, mineral veins, or lineations. They are crucial for understanding the spatial orientation and behavior of these features in three-dimensional space.
Trend
Definition: The trend of a linear geological feature is the direction in which the feature extends horizontally across the Earth’s surface. It is measured as a compass bearing.
Measurement:Trend is expressed as a compass direction (e.g., N30°E), indicating the general direction of the feature when viewed from above.
Usage: Trend is used to describe the horizontal projection of linear features such as fold axes, fault lines, or mineral veins.
Example: If a fault line extends from the northwest to the southeast, its trend might be described as NW-SE.
Plunge
Definition: The plunge of a linear geological feature is the angle at which the feature inclines relative to the horizontal plane. It describes how steeply the feature dips into the ground.
Measurement: Plunge is measured as an angle from 0° (horizontal) to 90° (vertical) and is usually combined with the trend to fully describe the orientation of the feature. The trend gives the direction of the line in the horizontal plane, while the plunge gives the angle of inclination.
Usage:Plunge is used to describe the vertical angle of inclination of linear features like fold axes, lineations, or the intersection line of two planes.
Example: If a fold axis trends N30°E and plunges 45° to the northeast, the feature extends in a northeast direction and dips into the ground at an angle of 45°.
Combined Usage
To fully describe the orientation of a linear feature in three-dimensional space, both trend and plunge are used together. This provides a complete understanding of the direction and angle at which the feature is oriented.
Example:Consider a fold axis with a trend of N45°E and a plunge of 30°. This means the fold axis extends in a northeast direction (N45°E) and dips into the ground at an angle of 30° from the horizontal.
Summary
Trend: The horizontal direction or compass bearing of a linear geological feature as it extends across the Earth’s surface.
Plunge: The angle of inclination of a linear feature relative to the horizontal plane, indicating how steeply the feature dips into the ground.
These terms are essential for geologists when mapping and analyzing the geometry of geological structures, as they provide a precise description of the orientation and behavior of linear features in the subsurface.
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