FE 02-16H Clastic Description

Nội dung text: FE 02-16H Clastic Description

1. Clastic Rocks: Rock Type Rock size Consolidated Unconsolidated Rudaceous Conglomerate Gravel Breccia Scree Tillite Till Arenaceous Sandstone Sand Siltstone Silt Argillaceous Claystone Clay Shale Clay / Mud
2. Clastic Rocks: Hardness and Induration • Common descriptions are: – Rudaceous and arenaceous rocks: unconsolidated, friable, moderately hard, hard and extremely or very hard – Argillaceous rocks: soluble, soft, plastic, firm, hard – Other descriptive terms: brittle, dense, crumbly, loose, amorphous
3. Hardness and Induration: Argillaceous Rocks: Definitions • Soluble – readily dispersed by running water • Soft – no shape or strength • Plastic – easily molded and holds shape; difficult to wash through a sieve • Firm – material has definite structure and shape; readily penetrated and broken by a probe • Hard – sharp angular edges; not easily broken by a probe
4. Clastic Rocks: Visual Porosity • 3 types of porosity: interparticle, moldic, fracture • The porosity in rudaceous and arenaceous rocks is primarily interparticle or intergranular • The theoretical maximum porosity for a clastic rock is about 26%. • Never use numerical values in estimating porosity, use descriptive terms
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