Architectural Geology of Rabat, Part 4: Send in the Restorationists | Morocco
Facing northeastward and looking at the side portal adjacent to the Bab Oudaya.
For the list of my primary sources for this series, see the bottom of the Part 1 essay.
In 1976 this relatively modest arched passage was the main entrance to the Kasbah. And it still is. But half a century ago, as this photo shows, it was in sore need of a substantial amount of restoration work. Not only had some of the arch-supporting stones of the doorframe fallen away; much of the rest of the rock was badly weathered.
This was especially evident in the whitened surfaces, which appear to be heavy deposits of salt-compound efflorescence that were leached out of the rock’s interior. That’s a plausible hypothesis, anyway, given the proximity of the saline Bou Regreg tidal estuary and the North Atlantic itself.
However, if you take a look at the modern version of this spot on Google Earth Street View, you’ll find that the locally quarried Salé Calcarenite used here has indeed been lovingly cleaned and restored. This distinctive if less than enduring stone, now once again sporting its original Earth-toned tints, began its career as shoreline bedrock located just across the mouth of the river. It ranges in age from the Pliocene to the present Quaternary period.
When I first started to research the Salé and its widespread use in Rabat, I was excited to find a second calcarenite in architectural use. The first I’d known of was southern Indiana’s redoubtable Salem Limestone. That Mississippian (Lower Carboniferous) selection, which since the latter part of the nineteenth century has been produced in huge quantities, is undoubtedly America’s most common building stone.
Calcarenite is perhaps the oddest form of limestone, and one that because of its granular texture is often mistaken for sandstone. It’s composed of calcareous fossil fragments glued together with still more calcite. There’s something about this composition that makes it a mason’s dream. It is handily sawn into sections of whatever size you wish, and it’s almost as easy to carve into finely wrought detail as a bar of soap.
Interestingly, since I began my Rabat album, I’ve come across two other examples of this offbeat sedimentary rock type that have been extensively utilized by Old World builders. The first of these, taken from the Pleistocene Agrigento Formation, was used for the incomparable complex of Doric temples erected by the Greek colonists of Akragas, Trinacria —now Agrigento, Sicily. In fact, those beautiful structures stand directly on the bedrock from which their stone was quarried.
The other calcarenite is the Miocene-epoch Marés Stone found on two Balearic isles, Mallorca and Menorca. It has been employed there for everything from the magnificent Palma Cathedral to simple farm-field walls. And in true calcarenite fashion, the Marés and the Agrigento are both renowned for their buff-to-golden coloration, and for their superb workability.
As I continue my rambling researches here and there, I wouldn’t be surprised if I stumble across still other architecturally significant varieties of this fascinating, fossil-rich rock.
To see the other photos and descriptions in this set, visit my my Architectural Geology of Rabat album..
Architectural Geology of Rabat, Part 4: Send in the Restorationists | Morocco
Facing northeastward and looking at the side portal adjacent to the Bab Oudaya.
For the list of my primary sources for this series, see the bottom of the Part 1 essay.
In 1976 this relatively modest arched passage was the main entrance to the Kasbah. And it still is. But half a century ago, as this photo shows, it was in sore need of a substantial amount of restoration work. Not only had some of the arch-supporting stones of the doorframe fallen away; much of the rest of the rock was badly weathered.
This was especially evident in the whitened surfaces, which appear to be heavy deposits of salt-compound efflorescence that were leached out of the rock’s interior. That’s a plausible hypothesis, anyway, given the proximity of the saline Bou Regreg tidal estuary and the North Atlantic itself.
However, if you take a look at the modern version of this spot on Google Earth Street View, you’ll find that the locally quarried Salé Calcarenite used here has indeed been lovingly cleaned and restored. This distinctive if less than enduring stone, now once again sporting its original Earth-toned tints, began its career as shoreline bedrock located just across the mouth of the river. It ranges in age from the Pliocene to the present Quaternary period.
When I first started to research the Salé and its widespread use in Rabat, I was excited to find a second calcarenite in architectural use. The first I’d known of was southern Indiana’s redoubtable Salem Limestone. That Mississippian (Lower Carboniferous) selection, which since the latter part of the nineteenth century has been produced in huge quantities, is undoubtedly America’s most common building stone.
Calcarenite is perhaps the oddest form of limestone, and one that because of its granular texture is often mistaken for sandstone. It’s composed of calcareous fossil fragments glued together with still more calcite. There’s something about this composition that makes it a mason’s dream. It is handily sawn into sections of whatever size you wish, and it’s almost as easy to carve into finely wrought detail as a bar of soap.
Interestingly, since I began my Rabat album, I’ve come across two other examples of this offbeat sedimentary rock type that have been extensively utilized by Old World builders. The first of these, taken from the Pleistocene Agrigento Formation, was used for the incomparable complex of Doric temples erected by the Greek colonists of Akragas, Trinacria —now Agrigento, Sicily. In fact, those beautiful structures stand directly on the bedrock from which their stone was quarried.
The other calcarenite is the Miocene-epoch Marés Stone found on two Balearic isles, Mallorca and Menorca. It has been employed there for everything from the magnificent Palma Cathedral to simple farm-field walls. And in true calcarenite fashion, the Marés and the Agrigento are both renowned for their buff-to-golden coloration, and for their superb workability.
As I continue my rambling researches here and there, I wouldn’t be surprised if I stumble across still other architecturally significant varieties of this fascinating, fossil-rich rock.
To see the other photos and descriptions in this set, visit my my Architectural Geology of Rabat album..