Some of the oldest rocks exposed at the surface in Jordan are situated in the southern Wadi al 'Arabah and date to the
Proterozoic.
Precambrian basement rock intrusions in the south include
aplite,
diorite,
gabbro and
granodiorite. From east to west, the number of dikes in Precambrian rocks increases.
Paleozoic (539-251 million years ago) East of the
Jordan River Valley, the land surface eroded to a nearly flat
peneplain and many Proterozoic sediments were eroded. Before
Cambrian sediments began to accumulate quartz porphyry lavas erupted to the surface. Tectonic conditions favored the preservation of Proterozoic sediments in the Wadi al'Arabah as Cambrian sandstones began to form. The continental, marine and calcareous sandstones accumulated as the
Tethys Ocean transgressed the region, followed by a late Cambrian marine regression marked by a return to more terrestrial sandstones. During the
Ordovician a new transgression flooded more of the land surface, leading to
argillite deposition and marine conditions persisted through most of the
Silurian except for a mid-Silurian interruption of red-brown sandstones. Nearshore and continental conditions persisted through the
Carboniferous, recorded by calcareous and continental sandstones.
Mesozoic (251-66 million years ago) The Tethys Ocean transgressed the landscape in the
Triassic, leaving a new sequence of sedimentary rocks with a disconformity with underlying Paleozoic rocks. Sea levels dropped in the Late Triassic and then rose in the
Jurassic. Volcanism and uplift came in advance of early
Cretaceous deposition. A major marine transgression reach the current Jordan River.
Marl and siliceous rocks deposited during continued transgression in the
Albian,
Turonian,
Santonian,
Campanian and
Maastrichtian, while continental deposition took place in the Nubo-Arabian Shield in the southeast. The Sirhan Basin, Al Jafr Basin and Al Azraq Wadi all accumulated significant sediment thicknesses.
Chert and
phosphorite layers are common from the period. On June 2, 2025 it was reported that Jordanian scientist Abbas Haddadin has uncovered seeds preserved in
amber from the Zarqa Sea region, dating back 140 million years, making them the oldest such specimens ever found. This discovery suggests that during this period,
Jordan had a tropical, humid, and rainy climate and was situated along the coast of the ancient
Sea of Tethys.
Cenozoic (66 million years ago-present) At the beginning of the
Cenozoic, through the
Paleocene and
Eocene, similar deposition to the Cretaceous took place, including bituminous limestone and marl. Rifting began in the
Oligocene, forming the Jordan Rift Valley. The resulting depression was probably occupied by a sequence of lakes or shallow marine environments. From the
Miocene through the
Pliocene, a marine environment that may have been a branch of the Mediterranean reached the Red Sea through the Rift Valley, reaching basalt flows in Djebel ed Drouz. Up to four kilometers of evaporites formed into the early
Pleistocene. ==See also==