Age dating of basalt
Age dating of basalt - Fille pornchat online
Within the lower part of the Cardenas Basalt, the lava is highly altered and might have been glassy at one time.Near the top of the lower unit the basalt is more massive and less altered.
The dikes typically are much thinner and locally follow fault planes.The Grand Canyon Supergroup, of which the Unkar Group is the lowermost part, overlies deeply eroded granites, gneisses, pegmatites, and schists that comprise Vishnu Basement Rocks.The Cardenas Basalt has also been called the Rama Formation.The lower unit ranges in thickness from 75 to 90 m (246 to 295 ft) and forms low, talus covered slopes.It consists of complexly interbedded, thin, and discontinuous beds of basalt, hyaloclastite, and sandstone.) in the eastern Grand Canyon, Coconino County, Arizona.
The lower part of the Cardenas Basalt forms granular talus slopes.The hyaloclastite is highly altered, and contains secondary chlorite, epidote, talc, and zeolites.Although this unit is highly altered and weathered, many of the primary features are preserved.The basal contact of the Cardenas Basalt with the underlying Dox Formation is smooth, planar, parallel to bedding and locally interfingering.In places the sandstones of the Dox Formation have small folds and convolutions that are indicative of soft sediment deformation.Thus, the contact between the Cardenas Lavas and the Dox Formation is conformable and interfingering.