MCQ Detailed View

Sedimentary rocks are a major type of rock found on the Earth’s surface. They are formed from the accumulation and compression of sediments, which are small fragments of minerals, organic material, and other rocks. Over time, layers of these sediments are deposited in rivers, lakes, oceans, and deserts, where they are compacted and cemented together to form solid rock.

One of the key characteristics of sedimentary rocks is that they are porous. This means that they contain tiny holes or spaces (pores) between their grains or particles. These pores allow water, oil, gas, and other fluids to pass through or be stored within the rock. The porosity of sedimentary rocks is due to the way they are formed – from loose materials that do not always fit tightly together, leaving gaps in their structure.

Examples of sedimentary rocks include sandstone, limestone, shale, and conglomerate. These rocks are important in many natural processes and human activities. For instance, aquifers, which store underground water, are usually made of porous sedimentary rocks like sandstone. Similarly, many oil and natural gas reservoirs are found in sedimentary rock layers because their porosity allows these resources to collect and be extracted.

In contrast:

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  Hard rocks such as granite are usually igneous rocks formed by cooling magma.

  
  


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  Rough describes texture but not a defining property of sedimentary rocks.

  
  


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  Brittle rocks can break easily, but not all sedimentary rocks are brittle.

  
  

The porosity of sedimentary rocks makes them crucial for groundwater movement, soil fertility, fossil preservation, and natural resource storage.

Thus, the correct answer is Porous, as this property defines the ability of sedimentary rocks to hold and transmit fluids through their interconnected spaces.