HONLEY WOOD QUARRY EARTHCACHE 

Honley Wood is one of West Yorkshire's largest remaining ancient semi-natural woodland areas.  In the early 19th century there was coal mining within the area, and there are also several abandoned quarries which are marked on the first OS map from 150 years ago.  The scars from these industries have now healed with just some evidence of what went on here remaining. Covering 150 acres, it is made up of several smaller woods including Greasy Slack Wood, Honley Wood and Honley Old Wood.  It is an important example of Pennine oak woodland according to a 2002 ecological survey and is a key part of the local forest habitat network.  If you're lucky you may spot one of the local deer in the woods, and see evidence of badger activity.  Also within the woods are earthwork boundaries, cairns, defensive earthworks and probable burial sites dating from the Bronze Age (2000-800BC) to the Iron Age (800-100BC).

The coordinates will take you to one of the old quarries, abandoned by the stone industry but enjoyed and utilised by climbing enthusiasts.  

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Formation of sedimentary rock

transport → deposition → sedimentation → compaction → cementation

Sandstone 

Sandstone is a sedimentary rock composed of tiny mineral particles and/or rock fragments. Pieces of broken rock get carried by a river, the wind or the sea until they are deposited, where, over time they build layers. This is called sedimentation.

As layer upon layer is formed, the upper layers press on the lower ones, squashing them, forcing the water out from between the bits of rock, causing crystals to form.  Those crystals cojoin, or cement, the pieces of rock, and over millions of years sedimentary rock is formed. 

Most sandstone is composed of quartz, a hard colourless or white mineral made of silica which does not break down chemically, or feldspar a common rock-forming mineral which is colourless or pale-coloured.  If there are impurities in the minerals or crystals, that can change their colour, therefore sandstone can come in any colour but predominantly brown, yellow, red, grey, pink, white, and black. 

Sandstone Quarry

Sandstones held together with quartz are resistant to chemical weathering, but if the cement is made up of clay or is rich in iron the sand grains can work loose and be washed away.  Sandstones with lots of bedding planes are more susceptible to decomposing.  Dependant on the make-up of the sediment and the conditions, some layers may be weaker than others resulting in brittleness, breakages and weathering.  The more quartz the more resistant the sandstone is to weathering.

Sandstone rocks

Sandstone has been used for thousands of years for construction, decorative stone work and tools.  The local drystone walls, old farms and cottages, churches and factories are constructed from sandstone as it is easy to work.  The sandstone in some areas has less resistance to weathering due to a higher sand composition, making it more friable (the condition of being friable, describes the tendency of a solid substance to break into smaller pieces under stress or contact, especially by rubbing.  Sandstones which does not break up under stress or contact are good for sharpening tools or grinding grain, such as grit stone or millstone grit.  

Limestone 

Limestone is also a sedimentary rock, but where sandstone is formed by tiny pieces of rock, most limestone is formed of the skeletal remains of marine organisms such as coral, forams and molluscs, along with impurities such as mud, sand or silt.   The remains of the marine organisms form the mineral calcite, and, mixed with the impurities and compressed over thousands of years, forms limestone.  Like sandstone, it may contain quartz and feldspar.  It is quite common to see marine fossils in large sections of limestone.

Limestone

Limestone rock containing fossils

Logging the cache.


From your observations of the rock at GZ please answer the following questions. Please send them to me, do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile. Answers must be submitted within 5 days of logging a find on the EarthCache.