Final answer:
The dome of Newgrange was constructed using a corbeled dome technique, which involves layering stones to create a stable, beehive-shaped structure without the use of mortar. This method demonstrates the sophistication of Neolithic engineering and differs from the post and lintel system or Roman and Gothic arch and vault systems.
Step-by-step explanation:
The structural system used for the dome of Newgrange is known as a corbeled dome. Derived from the Neolithic period, this building technique is evident in the passage tomb at Newgrange, which dates back to circa 3200 BCE. The corbeled dome technique involves laying stones in such a way that they form a sturdy vault, with each successive layer of stone slightly closer to the center than the layer below, gradually forming a beehive-like structure. This ancient method does not require any sort of mortar or cement, instead relying on gravity and the precision of the placement to prevent the structure from collapsing. The dome at Newgrange is particularly noted for its ability to remain water-tight, highlighting the sophistication of the engineering behind this prehistoric monument.
While the corbeled dome at Newgrange is an impressive example of Neolithic engineering, it should not be confused with the later Roman and Gothic architectural advances. Unlike the post and lintel system seen in structures like Stonehenge or the advanced arch and vault systems of Romanesque and Gothic architecture, the corbeled dome uses a simpler method that nevertheless required a high degree of skill and knowledge to execute. The longevity of the structure at Newgrange stands as a testament to the success and durability of this ancient construction method.