When scanning the region of Judean lowlands from a geological point of view, you can see the uniqueness of Maresha since it is located on a foundation of chalk rock. Chalk is a rock that resembles limestone, and both are composed of the mineral calcite, but unlike limestone, chalk does not have a crystalline structure. The result is that the chalk is crisp and soft compared to the limestone so that it can be relatively easily dug just like the cave we are about to enter. The chalk rock is also porous, but it does not pass water well, as its pores are very small and therefore it is a sealed rock.
Already, far back in history, the ancient inhabitants of Maresha knew the special characteristics of the chalk rock. In Maresha and the Judean lowlands, the chalk rock is covered by a layer of Caliche rock, which is much harder.
The ancient inhabitants broke the hard Caliche layer, whose thickness is between 1.5-3 meters. Then they began to carve the soft chalk rock, while using the excavated material to build their houses. The caves contained quarries of soft chalk that was used for the cement industry or for creating stones. Hundreds of caves were created from stone quarrying for construction purposes, when the quarry gradually expands downwards and creates bell-shaped caves. This cave was created sometime between the late Roman period and the early Arab period.
We are in the most impressive Bell Cave in Maresha, a huge quarry. The carvers carved a round and narrow opening in the Caliche layer, then went down while widening the cave, thus creating a bell shape. The cave reaches a height of 25m.
Working underground had several advantages: this region is characterized by extreme cold in the winter and high heat in the summer. The temperature inside the cave hardly changed during the year, so in winter the cave was warm, and in summer there was almost a feeling of natural air conditioning.
Bell Caves were dug either under houses whose main purpose in this case was to store water, or in open areas where they were mainly used as quarries of soft chalk that was used for the cement industry, for raw materials for the lime industry and for constructing stones. In some cases, the caves were used as cisterns. Characteristic of the cisterns is the staircase left by the carvers along its sides and the stone railings. The depth of Bell Caves ranges from several meters to 25 meters.
It is important to understand the need, especially in this region, for digging cisterns – in contrast to the Judean Mountains where many natural caves can be found and I will further explain. In the Judean Mountains, the hard limestone rock allows water to seep in, so that the water penetrates the thick soil, creating a chemical reaction with the limestone rocks, dissolves them, a process that initially creates cracks and over time cavities and stalactite caves. The water continues and penetrates until it encounters an opaque layer, where it stops as a layer of groundwater, which is sometimes discovered when it erupts as springs.
The situation in the Judean Lowlands is different. As I explained, here the soil is mainly chalk rock. The soft rock has porous, composed of fine grains, similar in nature to grains of flour. When they are in contact with water, they absorb the moisture, swell, and since the pores are very small, they are sealed and form a sealed layer that does not allow water to seep in. This feature is also the reason why in the Judean lowlands there is no groundwater, no springs and no natural caves.
Bell caves were sometimes used as craft and agricultural facilities such as oil mills, wineries and stables. Sometimes, during the quarrying, several bell caves that were adjacent to each other were combined into one large hall and there are several examples of this in Maresha. We reached the end, and as usual, I have a question for you, what phenomenon does the chalk rock creates in the Judean desert when rain falls? The answer will appear at the end of the video.