This article needs additional citations for verification. A simulated-color fort worth dating site image of Dallas and Fort Worth, Texas, taken by NASA’s Landsat 7 satellite. Dallas makes up much of the right half of the urbanized area. Red is vegetated area surrounding DFW.
Notice also the many reservoirs in the area. The geology of the DFW Metroplex consists of gently tilted sediments of mostly Cretaceous age, which also obscures a much older geologic record. Sediments older than Cretaceous can only be found at the surface in the extreme western part of the DFW Metroplex, in the area around Weatherford, Texas. The oldest rocks in Texas date from the Precambrian, specifically the Mesoproterozoic and are about 1,600 million years old, and mark the southern limit of the North American craton. The Fort Worth Basin which lies beneath Cretaceous sediments west of Dallas formed as a foreland basin during the Ouachita orogeny.
Gulf of Mexico at about the same time. Around 110-85 Ma, there was worldwide oscillatory increases in ocean floor spreading rates. The increase in the amount of basalt being injected into the ocean caused a displacement of water from the ocean basins, which resulted in sea level rise, flooding the coasts of the Texas margin and other bordering continents around the world. N-S trending belt of outcropping Cretaceous sediments. Cretaceous formations that lie from eastern Fort Worth to east of Dallas are part of the Gulfian Series. The Gulfian Series is known for the Cenomanian-Turonian transgression which deposited the mid-Cretaceous formations in the DFW Metroplex.
Transgression continued to occur after the deposition of the Woodbine, and created the Colorado Group which first created the Eagle Ford Shale which lies directly beneath west Dallas. The Austin formation consists of recrystalized, fossiliferous, interbedded chalks and marls. Exposures of Austin chalk are mainly seen in quarries, roadcuts, and stream beds where the water eroded the top soil. On top of the Austin Chalk are several different layers of beds known as the Taylor formation. Deposition of the Taylor beds marks the point of eustatic regression which continued until the end of the Cretaceous period. Ozan Marl is the first bed overlying the Austin chalk and can be found underneath the city of Richardson and Garland.
The last beds of the Cretaceous, which are also deposited directly over the Taylor formation and found east of Dallas are the Navarro beds. Navarro beds reflect anoxic waters at the time due to the shale present, and are a result of increased volcanic activity in the south-western part of the United States. People enjoy searching for fossils in the rocks around Dallas. Remnants of dinosaurs and Late Cretaceous marine reptiles such as Mosasaur are found. One species of mosasaur was named after the city: Dallasaurus turneri.