Laccolith

A laccolith is a type of igneous intrusion, specifically a mass of magma that has been injected between sedimentary rock layers, causing the overlying strata to bulge upwards, forming a dome-like structure. This geological feature results from the high viscosity of the magma, which prevents it from flowing freely and instead forces it to accumulate and lift the surrounding rock. Laccoliths are typically composed of intermediate to felsic rocks, such as andesite or dacite, and they can range in size from a few hundred meters to several kilometers in diameter. They are often associated with volcanic activity, though they might not necessarily break the surface as a volcano.

Laccolith meaning with examples

• The geologist pointed out the characteristic dome-shaped structure, a clear indicator that a laccolith had formed beneath the layers of sandstone. Careful examination revealed the solidified magma’s composition to be andesite. Evidence suggested the laccolith's formation occurred millions of years ago, resulting in significant deformation of the surrounding sedimentary layers. The surrounding environment also demonstrated that no further volcanic activity was expected in the near future.
• During their hike, the explorers encountered a prominent hill with gently sloping sides, their guide explained that this geological feature was the result of a laccolith. The magma injection had warped the layers of shale above it into a dome. Observing the surrounding landscape, they noted numerous erosion patterns indicating the long-term effect of geological uplift. Furthermore, analysis of the rocks confirmed a previous period of volcanic activity.
• Satellite imagery provided a global overview of the region, revealing several circular features indicative of potential laccoliths under the earth. The scientists were able to determine the size and shape of the underlying intrusions. Through further analysis, their primary objective was to determine the extent of erosion to the surface layer. They were hopeful that this could result in a way to extrapolate additional volcanic activity that could have taken place in the distant past.
• Mining operations had uncovered a section of a laccolith that contained veins of valuable minerals. Geologists were able to study the internal structure and composition, and use it to understand the geological history of the area. They confirmed that the magma had slowly pushed up the layers over time, resulting in distinctive sedimentary bedding patterns. These operations demonstrated how the laccolith formation impacted the landform.
• Researchers used seismic surveys to map the subsurface structure of the area, identifying a large, dome-shaped feature that strongly resembled a laccolith. By measuring the travel times of seismic waves through the rock layers, they obtained detailed information about the magma body. Further investigation of the seismic properties helped to understand the viscosity of the magma and the degree of uplift it caused, making the project beneficial to a greater degree of understanding.