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Geography

coral reefs

Complete Guide to Coral Reefs: Types, Formation & Threats

Coral reefs are marine ecosystems formed by colonies of coral polyps held together by calcium carbonate. These biodiversity hotspots support over 4,000 fish species and 800 hard coral species, earning them the nickname “Rainforests of the Sea.” Coral reefs require warm water temperatures (70-85°F), clear shallow waters, and adequate sunlight for their symbiotic algae called zooxanthellae to perform photosynthesis.

Geography

Types of Mountains: Formation, Classification & Examples

Mountains are elevated landforms created through various geological processes over millions of years. There are four primary types of mountains based on their formation: fold mountains (formed by tectonic plate collision), block mountains (created by faulting), volcanic mountains (built from accumulated volcanic material), and residual mountains (formed through erosion). The most recent mountain-building episode, the Alpine orogeny, began 30 million years ago and created today’s highest peaks including the Himalayas, Alps, Andes, and Rockies.

Geography

Complete Guide to Earthquakes: Types, Causes & Effects 2025

Earthquakes are sudden releases of energy from Earth’s crust that create seismic waves, typically occurring along fault lines. These geological events are classified into five main types: tectonic, volcanic, collapse, explosion, and reservoir-induced earthquakes. Understanding earthquake mechanics, measurement scales (Richter and Mercalli), and global distribution patterns is essential for comprehending their impact on human society and infrastructure. This comprehensive guide explores earthquake science, from crustal dynamics to safety preparedness.

Plate Tectonic Processes

The Theory of Plate Tectonics

The theory of plate tectonics explains how Earth’s outer shell is divided into large, moving pieces called lithospheric plates. These rigid plates float on the partially molten mantle beneath them, constantly moving at rates of 2-15 cm per year. The theory, developed in the 1960s by McKenzie, Parker, and Morgan, describes how new oceanic crust forms at mid-ocean ridges while old crust is destroyed at subduction zones, creating earthquakes, volcanoes, and mountain ranges.

Sea Floor Sprending

What is Sea Floor Spreading? Complete Guide to Plate Tectonics Theory

Sea floor spreading is a geological process where new oceanic crust forms at mid-ocean ridges as tectonic plates move apart. Proposed by Harry Hess in 1962, this theory explains how magma from the Earth’s mantle rises through fissures in the oceanic crust, solidifies into basalt, and creates new seafloor that gradually pushes continents apart. This process provided the crucial mechanism that was missing from Alfred Wegener’s continental drift hypothesis.

coral reefs

प्रवाल भित्ति क्या है? प्रकार, वितरण और महत्व

प्रवाल भित्ति समुद्री प्रवाल कीटों द्वारा निर्मित कैल्शियम कार्बोनेट संरचनाएं हैं जो 25°N से 25°S अक्षांशों के बीच उष्णकटिबंधीय सागरों में पाई जाती हैं। ये तीन मुख्य प्रकारों में विभाजित हैं: तटीय प्रवाल भित्ति, अवरोधक प्रवाल भित्ति और एटॉल। इनके विकास के लिए 20-30°C तापमान, उचित लवणता (27-30‰) और स्वच्छ जल आवश्यक है।