The Gheralta Sacred Landscape, which consists of the Gheralta ridge and the twenty-eight rock-hewn monuments carved into the sandstone, represents the first phase of the serial nomination. The geology of the Gheralta area is characterized by Precambrian rocks, Permo-Carboniferous sedimentary rocks, Middle Jurassic–Triassic to Early Cretaceous sedimentary rocks. The churches in this locality area are all carved into Enticho Sandstone or into Adigrat Sandstone. Enticho and EdagaArbi are glacial in origin (shale and tillites). Adigratsandstone, which overlies these glacial origin rocks, is typically yellowish to pink, fine to medium grained, well sorted and cross-bedding and quartz rich. In places Adigratsandstone is calcareous especially toward the top and near contact with the overlying carbonate rich units. Gheralta is a long ridge, with sides which are near vertical. These steep pillars are the last remnants of a thick sandstone plateau, now mostly eroded away, which were deposited in the Paleozoic as sediments washing out from large Gondwanan glaciers and they are found directly on top of folded, metamorphosed Precambrian gneisses. In places, basalt lava has pushed through a crack in the sandstone, forming a narrow intrusion, or dyke, which has then eroded away more rapidly than the sandstone, resulting in narrow passageways which lead into the sandstone massifs and act as informal stairways to a number of the churches.
The rock-hewn monuments of Gheralta, which are located at altitudes varying from approx. 2100 –2500 metres above sea level, have been carved into various levels of the sandstone, from the bottom to the top of the outcrop. The monuments were excavated at different dates over a period of 1,500 years, from the 5th – 14th centuries AD. Located in a spectacular landscape of great scenic beauty, access to many of them is extremely challenging and in some cases involves climbing vertical surfaces utilizing handholds and footholds cut into the rock, or by walking along a narrow ledge with a vertical drop below. Some of the earliest may originally have been tombs excavated during the period of the Axumite empire (ended c. 700 AD) and were converted to religious use at a later period. The structures hewn out of the rock to serve as churches from the firsts have plans with columns, arches, beams and domes which imitate conventional masonry and timber construction. Many of the churches contain wall-paintings, dating from 13th – 19th centuries. All churches remain in use, performing their original religious function, and many contain religious treasures in the form of manuscripts, portable paintings, crosses, crowns, sistra, drums and other religious artefacts.
Tembien Sacred Landscape
The Tembien Sacred Landscape incorporates twenty-eight rock-hewn churches. The geology of the Tembien area is characterized by Precambrian basement rocks, Permo-Carboniferous sedimentary rocks, Middle Jurassic–Triassic to Early Cretaceous sedimentary rocks and Cenozoic basalts. Among the Precambrian rocks, the Tembien Group (limestone, slates, and dolomites) and the Tsaliet Group (Meta-volcanics) are predominant. Generally in Tigray low-grade, meta-volcanic, meta-volcanoclastic, and meta-sedimentary rocks are intruded by syn- to late-tectonic granitoids and the meta-volcanic and meta-volcanoclastic rocks together forming the largest unit. The rock-hewn churches in these localities are sculpted into Enticho sandstone, Adigrat sandstone and Amba Aradam sandstone. Enticho sandstone is characterized by white, medium-grained sandstone, coarsely cross–bedded with silty beds and some iron rich layers. Adigrat sandstone in the Tembien area is soft and friable, with variegated colour (yellowish to reddish, and pinkish) and generally well-sorted. Toward the upper part of the unit it is generally whitish, friable, and well sorted. Amba Aradam sandstone is consisting of conglomerates, shale and its colour varies from whitish, purple, reddish to yellowish. It is generally coarse grained, friable to compact in strength.TembienDega, the highlands, consists of several mountain chains, cut by high passes which allow travel through the area. Erosion has formed spectacular rock bastions and pinnacles of various shapes and colours.
The rock-hewn churches date principally to the second half of the Middle Ages and are a product of the monastic renaissance which characterised the period. In contrast to the Gheralta and Atstbi Sacred Landscapes, the rock-hewn churches of Tembien therefore form a coherent group in terms of age and function. This is reflected in the fact that many of the churches belong to living monasteries. They are located at altitudes of approx. 1200 – 2800 metres above sea level, at a lower altitude than the Gheralta and Atsbi landscapes. Cycles of wall-paintings are few in number, but a notable exception if the church of Abba Yohanni, which contains both 15th-century wall-paintings and an impressive later series in the first Gondar style, dating to the early 17th century. Many of the churches possess important ecclesiastical treasures, especially manuscripts and crosses, including significant examples of medieval date.
Atsbi Sacred Landscape
The Atsbi Sacred Landscape lies at the eastern edge of the highland plateau, at the top of the escarpment which falls away into the Danakil Depression, parts of which lie below sea level. The area includes twenty-four rock-hewn churches, as well as three very early timber-and-masonry built churches. Atsbi Horst is composed of Precambrian rocks (e.g. meta-sediment, meta-conglomerate, Meta-greywacke, etc.) overlying by Permo-Carboniferous sedimentary rocks, Middle Jurassic–Triassic to Early Cretaceous sedimentary rocks (Enticho Sandstone and Adigrat sandstone), in places include dark brown ferruginous/ lateritic beds. The sandstone in the Atsbi area forms Mesa and butte into which most of the churches are sculpted. Steep-sided ambas (flat-topped mountains) rise out of the highland plateau and it is in their cliff faces that the rock-hewn churches are generally to be found, located at altitudes of between approx.2500 and 2900 metres above sea level.
Rock-hewn churches include the large, five-bay, basilica of Mikael Amba, of 8th – 10th centuries AD, which incorporates important early woodwork dating to the original excavation of the church. Other significant rock-hewn churches include Mikael Barka, Mikael Mitsua and Abuna AregawiAfa’anti. The church of Debra Selam Mikael is a cave church of timber-and-masonry construction with the upper parts and the rear wall carved out of the solid rock, and so is partially rock-hewn.TcherqosAgabo is a small timber-and-masonry church built against a rock overhang. Zarema Giyorgis is a free-standing-built structure. These three churches are amongst the oldest in Ethiopia and are amongst the oldest timber structures in the world, dating between the 6th and 10th centuries AD. Debra Selam Mikael has an outstanding and extensive series of wall-paintings, dating to the 11th / 12th century, whichare amongst the earliest and most important cycles of wall-paintings in Ethiopia, but wall-paintingsare also present in a number of the rock-hewn churches. Monastery churches in Atsbicontain many treasures.