Menuha Formation

Menuha Formation Stratigraphic range: Upper Cretaceous (Santonian) PreЄ Є O S D C P T J K Pg N ↓
Menuha Formation exposed in Makhtesh Ramon.
Type	Sedimentary
Unit of	Mount Scopus Group
Underlies	Mishash Formation
Overlies	Zihor Formation
Thickness	14 to 50 m
Lithology
Primary	chalk, marly chalk
Other	conglomeratic chalk, limestone
Location
Region	Makhtesh Ramon, Negev desert
Country	Israel
Extent	Israel

The Menuha Formation is the name given to an Upper Cretaceous (Santonian) chalk, marly chalk and conglomeratic chalk unit exposed throughout the Makhtesh Ramon region of southern Israel and parts of northern Israel (Avni, 1991).

Stratigraphy and paleoenvironment

The Menuha Formation records the earliest occurrence of the structural activity that formed the eroded anticline that is Makhtesh Ramon (Avni, 1993). It consists of white and yellow/brown chalk that is often glauconitic and sometimes conglomeratic or marly. The Menuha Formation likely represents a temperate to subtropical, outer continental shelf or middle slope environment. This is based on the occurrences of several shark and fish teeth, oysters, trace fossils, phosphatic peloids, and planktic/benthic foraminiferans. The isolated teeth represent at least ten different species:

• Cretalamna appendiculata
• Cretoxyrhina mantelli
• Squalicorax falcatus?
• Squalicorax kaupi
• Scapanorhynchus rapax
• Scapanorhynchus raphiodon?
• Carcharias samhammeri
• Carcharias holmdelensis
• Hadrodus priscus
• Micropycnodon kansasensis?

In order to sustain such a shark population, this environment would have also included plesiosaurs, ichthyodectids, mosasaurs, shrimp, and squid.

References

• Avni, Y. (1991). "The geology, paleogeography and landscape evolution in the central Negev Highlands and the western Ramon structure". Geological Survey of Israel, Report GSI/6/91: 153 p.. 

• Avni, Y. (1993). "The structural and landscape evolution of the western Ramon structure". Israel Journal of Earth Sciences 42: 177–188. 

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  Thalassinoides burrowing system throughout the Menuha Formation chalk.

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  Cretalamna appendiculata tooth, Menuha Formation.

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  Squalicorax kaupi tooth, Menuha Formation.

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  Squalicorax falcatus? tooth, Menuha Formation.

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  Carcharias samhammeri tooth, Menuha Formation.

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  Carcharias holmdelensis tooth, Menuha Formation.

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  Cretoxyrhina mantelli tooth, Menuha Formation.

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  Scapanorhynchus rapax tooth, Menuha Formation.

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  Scapanorhynchus raphiodon? tooth, Menuha Formation.

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  Hadrodus priscus tooth, Menuha Formation.

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  Micropycnodon kansasensis? tooth, Menuha Formation.

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  Several planktic/benthic foraminiferans replaced by silica from the Menuha Formation.

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  Several oysters, possibly Pycnodonte vesicularis, from the Menuha Formation.

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  Irregular echinoid spine from the chalk sediments of the Menuha Formation.