Field Trips
Groundwater in Cretaceous carbonates
Sunday 21st June
Led by Lou Maurice (British Geological Survey), Tim Atkinson (University College London) and Andy Farrant (British Geological Survey)
The Cretaceous Chalk Group is Britain's most important aquifer providing over 50% of the potable water supplied to London and the southeast.
It is widely accepted that the high transmissivity values that make the Chalk such a productive aquifer result from enlargement by dissolution of a primary fissure network and that a diagnostic feature of karst groundwater systems is a permeability structure dominated by conduits dissolved from the rock and organised to facilitate the circulation of fluids.
However, in the past the Chalk was widely regarded as being ‘non-karstic’ because of an absence of caves. More recently the Chalk has been recognised as being at one end of a spectrum of flow types in carbonate groundwater systems and it has also become apparent that there is a range of flow systems within the Chalk.
In particular, where there is a thin Palaeogene cover there are commonly significant karst features including dry valleys, dolines (sinkholes), stream-sinks and rapid groundwater flow to springs.
The field trip will visit an area with stream-sinks, dry valleys, springs and boreholes and discuss the groundwater hydrology including results of water tracing experiments. Solution features developed at the contact between the Chalk and Palaeogene cover will be viewed at disused quarry sites.
The fee of £40 for this field trip includes the coach travel to and from Birmingham and a packed lunch. Participants are advised that a certain degree of physical fitness is required for the walks that form part of the trip.
Dudley canals and historic limestone mines
Tuesday 23rd June
Led by Graham Worton (Dudley Museum)
The Black Country to the west of Birmingham was at the heart of the innovations that drove the Industrial Revolution. This is an opportunity to use the oldest surviving industrial canal tunnel in the UK, work for which began in 1775.
The host rock is the Silurian Wenlock or Dudley Limestone, the original type area for rocks of this age. There are no known cave or karst features in this area and there has been little research into the hydrogeology.
The specially arranged tour through the canal will facilitate examination of the rock structure and point inputs of water with abundant speleothem which are indicative of conduit flow.
The limestone is not sufficiently productive for water supply but the abandoned stone workings are locally flooded and presumably fed by dispersed recharge. Outcrops in the National Nature Reserve provide an opportunity to consider recharge processes.
The cost of this trip will be £20, which covers coach travel from Birmingham, the underground boat trip and refreshments. There is a limit of 48 participants. Physical activity – a walk of several hundred metres on level ground and climbing into the narrow boat.
Groundwater in Jurassic carbonates
Thursday 25th June
Led by, Tim Atkinson (University College London), Andy Farrant (British Geological Survey) and Lou Maurice (British Geological Survey)
The Jurassic carbonates are Britain’s third most important aquifer and in common with the Chalk they have high transmissivity values that result from enlargement by dissolution of a primary fissure network but have commonly been assumed to be non-karstic because there are few caves.
The field trip will focus on the Oolitic limestone which exhibits many karst features, including dolines (sinkholes), dry valleys and stream-sinks that have been shown by water tracing experiments to flow rapidly to large springs.
This will provide opportunities to discuss the limestone geology, structure, fractures and hydrology, speleogenetic inception and early karst conduit formation within the local geomorphic setting.
The fee of £40 for this field trip includes the coach travel to and from Birmingham and a packed lunch. Participants are advised that a certain degree of physical fitness is required for the walks that form part of the trip.
Groundwater in Carboniferous carbonates
Friday 26th June
Led by John Gunn (University of Birmingham), Paul Hardwick (RPS Planning & Development) and Steve Worthington (Worthington Groundwater)
Massive shelf and related marginal limestones of Dinantian age, belonging to the Carboniferous System, crop out extensively in northern England, the Peak District, North Wales, South Wales (extending into the Forest of Dean), and the Mendip Hills.
Commonly known as the Carboniferous Limestone, they contain the most complete assemblage of surface karst landforms and the largest, best developed, underground drainage networks in Britain, with more than 600km of surveyed cave passage.
The field trip will traverse the Peak District karst much of which is situated within Britain’s first National Park. There will be stops to visit two contrasting tourist caves, stream sinks, a spectacular dry valley that occupies a Carboniferous inter-reef channel, springs that exhibit complex non-linear discharge patterns and a disused quarry with excellent paleokarst.
The fee of £45 for this field trip includes the coach travel to and from Birmingham, admission to show caves and a packed lunch. Participants are advised that a certain degree of physical fitness is required for the walks that form part of the trip.