LIMESTONE AND SALT PANS AT XLENDI TOWER
Near Xlendi Tower, you will get to see the great Xlendi Cliffs, some beautiful seashore with salt pans and amazing natural creations originated from limestone.
THE SALT PANS
The salt pans are part of the centuries-old Gozitan tradition of Sea-Salt production that has been passed down within certain families for many generations. The pans are formed from the rocks they occupy, having been carved out by locals. The stone in which they are carved is made up of calcium carbonate and it also contains silica, clay and silt.
The formation process of the salt begins when sea water starts to fill crevices in the coastline. This sea water is left to settle for eight days before it is moved to smaller salt pans that are warmer in and further away from the sea. At the beginning of the drying process the water takes on a reddish hue and salt crystals begin to form. Once collected, the salt is stored in caves that have been carved into the coastal rock.
The salt pans in Xlendi are no longer in use, but you can collect a little bit of salt, that has naturally formed by itself.
STRATIGRAPHY OF THE MALTESE ISLANDS
The bedrock geology of the Maltese Islands consists of relatively young sedimentary strata originally deposited as marine sediments about 30 to 5 million years ago during the Oligocene and Miocene epochs. The resultant rock sequence consists of five formations laid on top of each other.
Lower Coralline Limestone Formation: This is the oldest formation exposed on the Maltese Islands (Oligocene, Chattian). It is a hard, pale grey limestone consisting of beds containing marine calcareous coralline algae deposited in a shallow water environment. This formation can be over 140m thick in exposed sections and forms prominent steep cliffs ranging from tens to over a hundred meters high particularly on the south western coasts of the islands such as Xlendi in Gozo and Dingli in Malta.
Globigerina Limestone Formation: This formation overlies the Lower Coralline Limestone Formation (Miocene, Aquitanian to Langhian). It is a soft, yellow, fine-grained limestone varying in thickness from some 20m (North West Gozo) to over 200 m (South East Malta). This formation is abundant in planktonic globigerinid foraminifera deposited in deeper waters than the underlying Lower Coralline Limestone. It contents many visible fossils and is further subdivided into the Lower, Middle and Upper Globigerina Members.
Blue Clay Formation: This formation overlies the Globigerina Limestone Formation and consists of medium grey and soft pelagic marls (Miocene, Langhian to Tortonian). The thickness of this layer varies considerably. It is over 70 m in the western parts of Malta but is completely absent in the easternmost parts. It was deposited in a deep water depositional environment similar to the underlying Globigerina Limestone Formation.
Greensand Formation: This formation (Miocene, Tortonian) is much thinner than the other four formations. It consists of friable, brown to greenish glauconite-rich sands occurring above a marked erosion surface truncating the Blue Clay Formation. It is green in colour when freshly exposed but turns brown when weathered. It reaches a maximum thickness of 11m at Il-Gelmus in Gozo. Elsewhere in eastern Gozo and throughout Malta the formation is rarely more than 0.5 m in thickness and has a sharp basal contact with the Blue Clay.
Upper Coralline Limestone Formation: This is the youngest formation in the Islands (Miocene, Tortonian to Messinian) having a thickness which can exceed 160 m and is well developed in western Malta and eastern Gozo. It is a hard pale-grey limestone deposited in shallow waters characterised by the presence of abundant corals and coralline algal fossils.
(source text and graphic: Continental Shelf Department / Gov. of Malta)
After studying the listing, please go to the given coordinates From here you have an overview of the salt pans and and the reference point is in sight. Answer the following questions about salt pans and limestone:
A What is the fundamental commonality of Sea Salt and Rock Salt? think about it in geological context
B Collect some naturally grown salt grains.
What size do the grains have approximately? (Not to be answered in storm and rain)
Now go to the reference point.
Here you can discover a special rock formation.
C Name the approximate size in meters (length, width, height)
D Circle the object: which different inclusions can you see in this rock?
E Describe the different sediment layers of the salt pans and the rock formation (colour, texture)
F (optional): Which two main sediment layers can be found here?
G (optional) It would be nice to have a picture of you together with
your GPS posted with your log.
To log the cache, please send me the answers (in english or german) through email or message. Do not hesitate to log "found it", I will contact you if your answers need more information. Please note, that logs without an answer cannot be accepted and will be deleted without further notice.
Have fun discovering the area!