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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.
The statement that oceanic crust cannot be older than 200 million years is based on the process of plate tectonics and the concept of seafloor spreading. Oceanic crust is continuously being created at mid-ocean ridges through volcanic activity, where magma rises to the surface, cools, and solidifiesRead more
The statement that oceanic crust cannot be older than 200 million years is based on the process of plate tectonics and the concept of seafloor spreading. Oceanic crust is continuously being created at mid-ocean ridges through volcanic activity, where magma rises to the surface, cools, and solidifies, forming new crust. As this process occurs, older crust is pushed away from the ridge and eventually subducted beneath continental plates or other oceanic crust in subduction zones.
Since the theory of plate tectonics suggests that the oldest oceanic crust is typically no more than around 200 million years old, this implies that older oceanic crust has been recycled back into the Earth’s mantle through subduction. This process effectively renews the oceanic crust, preventing it from accumulating to ages much older than 200 million years.
However, it’s important to note that there are exceptions to this general rule. Some fragments of ancient oceanic crust, known as ophiolites, can be found in certain geological settings, such as mountain belts, where they have been preserved and uplifted through tectonic processes. These ophiolites provide valuable insights into the history and evolution of oceanic crust, but they are relatively rare compared to the ongoing formation and recycling of younger oceanic crust at mid-ocean ridges and subduction zones.
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