Materials & Soils — Clay for Brick-Making In traditional construction, which soil type commonly provides the plastic, fine-grained clay used to make bricks for house construction?

Introduction / Context:
Bricks are typically made from fine-grained, plastic clays that can be molded, dried, and fired. The suitability of soil for brick-making depends on texture, mineralogy, and the presence of salts or organic matter. This question asks you to identify the soil source that commonly supplies workable brick clays in many regions.

Given Data / Assumptions:

• Good brick earth needs fine particles (clay/silt) with manageable plasticity.
• Excess salts (saline/alkaline) cause efflorescence and weakness.
• The query is at school level and seeks the most common, practical source.

Concept / Approach:
Alluvial deposits along rivers often contain layered silts and clays that, after proper mixing and tempering, make good bricks. Laterite soils can be cut into blocks (laterite stone) but are not the standard plastic clays for molded bricks. Black soils (vertisols) shrink–swell strongly and need careful processing; saline–alkali soils are unsuitable due to soluble salts and poor structure.

Step-by-Step Solution:

Verification / Alternative check:
Handbooks on brick-making emphasize riverine/alluvial clays and silts as common raw materials, subject to testing and blending for optimal performance.

Why Other Options Are Wrong:

• Black soil: High shrink–swell; not a preferred universal choice without modification.
• Laterite soil: Used as stone blocks; not typical plastic brick clay.
• Saline and alkaline soils: Detrimental salts lead to efflorescence and weakness.

Common Pitfalls:
Assuming any clayey soil is fine; soluble salts and organics must be controlled to avoid firing defects.

Final Answer:
alluvial soil