Altmühltaler Kalksteine e.V.

Jura Limestone

History of Origin

Approximately 160 million years ago a tropical ocean surrounded the southern Frankonian Alb. This flat shelf sea covered the entire southern German area and formed the connection between the North Sea and the alpine Mediterranean Sea (Tetys). Within a time span of 20 million years the sediments that were collected in the lagoons of the shelf sea lead to the formation of the upper Jura also known as White Jura or Malm. They are made up of light lime and marl which is a mix of lime (from the Tetys) and clay (from the North Sea).

The cause of the sedimentation was a  chemical process. The heat induced precipitation of lime from the Tetys waters. This process followed a set time pattern that was subject to climatic changes. Depending on the dissolved parts contained in the water, the sediments that formed at the bottom of this shallow ocean were either of marl or lime. These formations lead to the distinctive lime/marl alternations growing to reach a thickness up to 500 meters. Layers in the Treuchtlingen/Eichstätt area, where Jura limestone and Solnhofen natural stone are quarried, have walls reaching of up to 250 - 300 meters in thickness.

The sediments contain a large number of fossilized plants and animal life of that time period. Through inherent pressure, the sediment hardened and formed what is known today as Jura limestone and Solnhofen natural stone. Jura limestone had its origins in a time before Solnhofen natural stone. It is the result of lime deposit during the Mesozoic period, a time over 180 million years ago. This sedimentary rock is mainly made up of carbonaceous calcium (CaCO3) with an addition of metal oxides and alumina. The deposits are found in the Frankonian mountain range in the area of Kipfenberg - Eichstätt - Weißenburg -Treuchtlingen in a total height of 45 meters with single layers as high as 160 cm. Stones found in this area can reach a majestic size of 45 meters. Its beds can reach a thickness of up to 1.2 meters. However, it is only the stone found in the lower part of this formation that can be used as actual building material. These consist of 25 layers that are suitable for quarrying. The total thickness of all usable beds can reach up to 20 meters. Only 50% of the quarried stone actually ends up on the market. The remaining stone along with the 10 to 20 meters high covering stone and soil are used to produce gravel and cement.

A unique geological feature of the Jura limestone is that it covers an extensively wide area. In a radius of 22 square kilometres  the layers remain the same in their course and sequence thereby guaranteeing quality consistency even in the case of high demand.

 

Jura limestone and Solnhofen stone actually belong to the soft rocks. It's level of hardness goes from 3 to 3.5 on the Mohr scale (1-10). A diamond, in contrast, counts as the hardest material and is placed on level 10. Nevertheless, this fine grained Jura limestone differentiates itself from conventional soft rocks through the excellent polishability of its surfaces derived from the extreme density of its material. Hence, the reason why this natural stone is referred to as Jura limestone. The various colors displayed in Jura limestone stem from diverse iron compounds running throughout the stone. Its hues of color cover a wide spectrum ranging from cream white to golden yellow all the way to greyish blue. The quarry area of Jura limestone is the  Frankonian mountain range which lies in Bavaria. It's triangular borders include the towns of Treuchtlingen, Petersbuch and Eichstätt. Quarrying has left a visible footprint in this area. Shiny white quarries and dumps have become the region's landmark in which quarrying has had a long history dating as far back to the time of the Roman Empire.

It is the density, the polishability, the abundant color and structural variations and its high resistance to abrasion that make up its characteristics for the many possible applications of Jura limestone and Solnhofen natural stone. It can be used in interior design in form of a facade panel, split face, flooring or wall veneer as well as in large scale construction. Due to its high capacity of storing heat, the stone is especially suitable for flooring over water heating systems or electrical floor heating systems. These completely environmentally compatible stones serve as a symbol for timelessness and longevity. Their history as construction material dates back to the Roman era.  During this time, they utilized the stone's high durability and low maintenance and built with it their homes and fortifications. Today, natural stones are still implemented in a variety of ways ranging from private home installation to more prestigious buildings calling for an elegant design while providing for a solid solution. These include hotels, theatres, restaurants, museums, schools, churches and administrative buildings. Every piece of Jura limestone is a uniquely selected stone each expressing its own individual design and ambiance.

With its 150 million year old history, Jura limestone is the result of a unique geological  process. Each individual stone contains numerous specimens of plant and animal life implanted in its material. It is the natural power that led to its creation combined with its visible documentation of geological history that makes Jura limestone so charming and appealing. Be it an artificially made product or another form of natural stone, no other material can express the radiance of Jura limestone.

The colors displayed on your monitor are dependent upon your device's features and are subject to variation. The image shown is a mere approximation and, therefore, cannot guarantee for complete accuracy. Moreover, natural stone varies in color, texture and structure. The few examples show its impressiveness through its diversity and charm.


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