subtopic

Hot and humid environment, water-soluble rocks

On the ground: ravines, depressions, peak clusters (connected to the base), peak forests, solitary peaks, residual hills (the surface undulations first become larger and then become smaller), depressions, dams (materials eroded and accumulated from mountains have better fertility) Underground: Karst cave (the top material collapses and becomes a sinkhole (above ground), Tiansheng Bridge underground river

Water, carbon dioxide and carbonic acid content in the air decrease and calcium carbonate precipitates.

Above ground: travertine (stalactites on the ground, calcification pools) Underground: stalactites, stalagmites, pillars, stone curtains (curtains)

Southwestern region, karst poverty

1. The terrain at the junction of tectonic plates is rugged and broken, and geological disasters occur frequently. 2 Difficulties in road construction (unstable foundations, high bridge-to-tunnel ratio, underground water spraying, etc.) and inconvenient external transportation 3. Rocks are highly permeable, making it difficult for surface water to flow, and there are many underground rivers with insufficient water resources. 4. Heavy rainfall on the slope has eroded the land, and the fertility is insufficient. The soil layer is thin, and the contradiction between man and land has become prominent. Land reclamation has aggravated rocky desertification.

Strong water permeability, eye in the sky. Tourism resources

Continental red bed deposits characterized by steep cliffs Sedimentation (continental phase) uplift erosion (flowing water/freeze-thaw weathering)

From the top of the mountain to the foothills, the vegetation types are different (analyze the reasons based on the control, topography, soil, wind, sunlight, dryness and wetness)