地理漫步·世界地理英语30篇（3）

24 / 30

德干暗色岩：火山地层作为地貌记忆

The Deccan Traps cover 500,000 km² of west-central India with layered basalt flows up to 2,000 meters thick.
These eruptions occurred over ~1 million years around the Cretaceous-Paleogene boundary, possibly influencing global climate and extinction events.
Each flow unit cooled at different rates, creating columnar jointing, weathering-resistant plateaus, and fertile black cotton soils.
River valleys like the Godavari cut vertically through trap layers, exposing cross-sections that reveal eruption frequency and gas content.
Lava tubes and basalt caves host unique bat colonies adapted to stable, cool, high-CO₂ microclimates.
Geographers analyze how trap topography directs monsoon winds, causing sharp rainfall gradients across short distances.
Laterite caps form selectively on older flows, indicating past humid climates and guiding groundwater recharge modeling today.
Urban expansion in Pune and Nagpur confronts engineering challenges posed by fractured basalt aquifers and variable bedrock depth.
Satellite thermal imaging detects subtle surface temperature differences linked to subsurface flow pathways in weathered traps.
Rather than viewing volcanism as a single catastrophic event, this province demonstrates how layered time becomes tangible terrain.