Lamproite pipes form at which part of cratons?

• A. Center
• B. Edges
• C. Throughout
• D. Inside core

Answer: (B)

Lamproite pipes form at the edges of cratons. Cratons are thick, cold, and mechanically strong in their interiors, which tends to impede deep-sourced magmas from reaching the surface there. At craton margins, however, the lithosphere is weaker and often cut by sutures, faults, and zones of extension. These structural weaknesses provide ready-made paths for mantle-derived, volatile-rich lamproite magmas to ascend and erupt as pipes. This marginal setting contrasts with the craton center, where the conditions are less favorable for such rapid ascent, and explains why lamproite pipes are typically found near craton edges rather than throughout the interior.