Drilling 250 Million Years Into The Past!

The team were recently in Devon sinking a number of wireline rotary boreholes into the Alphington Breccia Formation to assess the depth and mobility of groundwater prior to development.

The Alphington Breccia Formation is a geologically interesting strata, comprised of angular fragments of other rocks, held together by finer clay and/or silt-based material known as a matrix. The rock was created during the Permian Period, over 250 million years ago, when flash floods in mountainous regions caused intense weathering of local rock and subsequent deposition in low-lying valleys and deserts via fast flowing rivers.  

While most rock fragments in the Alphington Breccia Formation are sandstone and shale, it isn’t uncommon to encounter horizons of lava and igneous material. Indeed, during our investigation we encountered horizons of Quartz-Porphyry within the Breccia, hinting at the geologically active past beneath Devon.