Introduction
At the given coordinates, you will find Clitheroe United Reformed Church. The rainwater is slightly acidic here, causing fossils to be visible.
The Church
The church is located in Clitheroe, a small town in Lancashire.
The Church Wall
The church walls are made of limestone. This is subject to chemical weathering. This is visible as there’s ‘less’ rock there as it has dissolved.
Limestone
Limestone is an organic, sedimentary rock. This means it was formed from the remains of tiny shells and micro-skeletons deposited on the sea bed. Over the years this sediment was compressed to form solid rock.
Limestone areas are predominently affected by chemical weathering when rainwater, which contains a weak carbonic acid, reacts with limestone. When it rains limestone is dissolved.
Marble
Marble is a rock formed when limestone is exposed to high temperatures and pressures. Marble forms under such conditions because the calcite forming the limestone recrystallises forming a denser rock consisting of roughly equigranular calcite crystals.
Chemical Weathering
Chemical weathering is the erosion or disintegration of rocks, building materials, etc., caused by chemical reactions (chiefly with water and substances dissolved in it) rather than by mechanical processes.
Types of Rocks
There are 3 types of rocks.
Sedimentary -
A river carries, or transports, pieces of broken rock as it flows along. When the river reaches a lake or the sea, its load of transported rocks settles to the bottom. We say that the rocks are deposited. The deposited rocks build up in layers, called sediments. This process is called sedimentation.
The weight of the sediments on top squashes the sediments at the bottom. This is called compaction. The water is squeezed out from between the pieces of rock and crystals of different salts form.
The crystals form a sort of glue that sticks or cements the pieces of rock together. This process is called cementation.
These processes eventually make a type of rock called sedimentary rock. It may take millions of years for sedimentary rocks to form.
Igneous -
Igneous rocks are formed from molten rock that has cooled and solidified.
Metamorphic -
Metamorphic rocks are the rocks formed from other rocks. They are sedimentary, metamorphic or igneous rocks that have undergone changes as a result of extreme pressure and heat. The name defines their formation whereby ‘meta’ means change and ‘morph’ means ‘form.’ Hence, metamorphic rocks are those whose forms have been changed through geological process such as large tectonic movements and magma intrusions.
Fossils
Fossils are organic products which are preserved in the Earth's crust. This means that the fossil is usually formed on or under (but not too deep!) the Earth’s surface or under the water.
PLEASE EMAIL OR MESSAGE ME ON MY GEOCACHING PROFILE WITH THE ANSWERS TO THE QUESTIONS. ONCE YOU HAVE SENT THE ANSWERS, YOU MAY LOG THE CACHE.
To log this EarthCache, please go to the given coordinates and answer the following questions.
1. Look at the rocks in the church wall. Please describe the appearance of the rocks.
2. Please describe the fossils on the rocks of the church wall. Please measure the size of some. Please say if these are similar in size or different in size.
****************** ********************
For full information on how you can expand the Church Micro series by sadexploration please read the Place your own Church Micro page before you contact him at churchmicro.co.uk
See also the Church Micro Statistics and Home pages for further information about the series.
****************** *******************