Pragnya IAS · Chapter 2 of 15 · Earth systems & tectonics
Tectonic plates map: major and minor boundaries
Distinguish plate interiors, divergent ridges, convergent trenches and transform faults.
STUDY NOTE 1
Three boundaries, three motions
Divergent boundaries separate plates and commonly form oceanic crust at ridges. Convergence can involve subduction or continental collision. Transform boundaries accommodate lateral motion without systematically creating or consuming crust.
STUDY NOTE 2
Small plates matter
Nazca, Cocos, Juan de Fuca, Caribbean, Arabian, Philippine Sea and Scotia are useful examples beside the large Pacific, Eurasian, African, Antarctic and American plates. Plate subdivisions and nomenclature vary between scientific models.
STUDY NOTE 3
India and Australia
Some introductory maps combine the Indian and Australian plates. More detailed models distinguish them and recognise a broad diffuse boundary across the Indian Ocean. A textbook’s simplified label should not be treated as an exact modern boundary survey.
STUDY NOTE 4
Link landforms to motion
The Red Sea records extension between Arabia and Africa. The Andes relate to Nazca–South America convergence; the Himalaya to India–Eurasia collision. The San Andreas is principally transform, whereas the Mid-Atlantic Ridge is divergent.
Map reading activity
Compare the Mid-Atlantic Ridge, San Andreas fault, Andes and Himalaya. Draw an arrow pair for each boundary and state whether ocean crust is formed, consumed, or neither.
What does this major & minor plates: moving boundaries lesson explain?
Divergent boundaries separate plates and commonly form oceanic crust at ridges. Convergence can involve subduction or continental collision. Transform boundaries accommodate lateral motion without systematically creating or consuming crust.
UPSC map practice & Geography Optional connection
For UPSC GS I and Geography Optional physical geography revision, connect the spatial pattern with the process in the study notes. Draw a small labelled sketch, explain the mechanism and distinguish conceptual models from observed datasets. These are Pragnya-authored exercises, not official UPSC previous-year questions.
References & original artwork
This lesson covers chapter 2 of the supplied reference curriculum. Pragnya IAS notes, activities and questions are independently authored; source PDF pages, branding, personal watermarks and unverified PYQs are not republished. Earth image: NASA Blue Marble, distributed via WebGL Earth; resized and compressed for this lesson. World coastlines: Natural Earth public-domain 1:110m land, simplified. These are educational concept views, not legal boundaries, forecasts or navigation maps.