A hillwalker's guide to the geology and scenery
Paul Gannon (2010) Pesda Press Ltd
This is one of several books which contain geology walks. I hope to do some of these next year, maybe combining walks from several books. In this blog entry I will be going through the first 8 chapters which are about the Peak District geology.
Chapter 1 - basement blocks
We start off with a description of the position of the PD at this time, south of the equator and slowly moving north. To the north is a mountain range, and an arc of higher ground to the south (the Wales-Brabant high) from which the Peaks High pokes out. To the north of the Peaks High is the Edale Basin and the the west the Widermerepool Gulf. The area is under extension causing the basins to sink.
Chapter 2 - layers of limestone
Limestone was formed in the shallow seas of the continually sinking basins and on the Peaks High when it went below sea level. Occasionally the sedimentation stopped as the plateau was above sea level (plant roots and soil found between some bedding. This forms the shelf limestone which was a lagoonal environment. At the edge of the shelf are apron reefs which are made from an algal reef and often have fore-reef and back-reef structures. The form a rim around the shelf limestone except in the south west where there is a ramp down to the Widermerepool Gulf. Knoll reefs formed within the main platform and are also known as mud mounds.
Chapter 3 - grains of grit
Sandstone formed by erosion of mountains in north forming deltas into freshwater (and occasionally seawater) in the sinking basin. It is the presence of layers of shale which forms the distinctive step and shelf topography.
Chapter 4 - lingering lignin
Coal was formed in a swampy tropical forest closer inland from the delta lobes. These forests were formed by plants which had a much higher proportion of bark and therefore lignin than modern trees.
Chapter 5 - faulted and folded
At the end of the Carboniferous and into the Permian plates crashed together to the south (finishing the assembly of Pangea). This halted the subsidence and instead the subsided land popped up on existing faults. The harder base of the white peak prevented serious folding resulting in the gentle dome of limestone. Especially to the west much folding took place resulting in many synclines and anticlines. Faults caused by the movement were mineralised by this tectonic activity.
Chapter 6 - drainage delights
Spring lines and landslips.
Chapter 7 - solution and superimposition
Sink holes, caves, dry valleys, stalactites and superimposed drainage.
Chapter 8 - peak and people
Exactly what it says.
The walks:
Walk #1 Kinder Scout
Walk #2 Bretton Clough
Walk #3 Mam Tor & Back Tor
Walk #4 Upper Dove & Manifold Valleys
Walk #5 Chrome Hill
Walk #6 High Wheeldon
Walk #7 Dove Valley - Wolfscote Dale
Walk #8 Lower Dovedale
Walk #9 Stanage Edge
Walk #10 Curbar Edge
Walk #11 The Roaches & Gradbach Hill
Walk #12 Lathkill Dale
Walk #13 Cave Dale & Winnats
Walk #14 NSC, Middleton Moor & Black Rock
Walk #15 Wye Valley
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