The Matmor Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

of up to thick, that is exposed in

Hamakhtesh Hagadol HaMakhtesh HaGadol ( he, הַמַּכְתֵּשׁ הַגָּדוֹל, ''lit.'' The Big Crater) is a makhtesh, a geological erosional landform of Israel's Negev desert. It measures 5 x 10 km. A makhtesh has steep walls of resistant rock su ...

in southern Israel. The Matmor Formation contains fossils from a

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

equatorial shallow marine environment. Bivalves, gastropods,

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and ...

echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

s, and sclerobionts are present in the Matmor Formation to various degrees (Wilson et al., 2010). The stratigraphy of the Matmor Formation consists of alternating layers of

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

and marl (Hirsch and Roded, 1996).

Stratigraphy

The

Iraq Petroleum Company The Iraq Petroleum Company (IPC), formerly known as the Turkish Petroleum Company (TPC), is an oil company that had a virtual monopoly on all oil exploration and production in Iraq between 1925 and 1961. It is jointly owned by some of the worl ...

originally described the

sequence in Hamakhtesh Hagadol of Israel in the 1930s (Hudson, 1958). These findings were later described and published by Blake (1935). Shaw (1947) published a limited summary of the stratigraphy. Hudson (1958) later subdivided the rocks into the

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

, Divesian, Argovian, Sequanim

biostratigraphic Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bio ...

stages. In 1963, Goldberg subdivided the section into the Zohar, Kidod and Be'er Sheva Formations. Goldberg (1963) further divided the Zohar Formation into the Ziyya and Madsus members. In 1966, Mayac dated the

and what appeared to be the Lower Oxfordian stages with

forams Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an ...

(Mayac, 1966, in Hirsch and Roded, 1996). Further biostratigraphic work by Hirsch et al. (1998) and Grossowicz et al. (2000) show that the Matmor Formation is entirely Late Callovian.

Gallery

Image:MakhteshGadolCenter02.jpg, Marls and

s of the Matmor Formation exposed near the center of Makhtesh Gadol Image:GastrochaenolitesMatmor.jpg, '' Gastrochaenolites'' boring in a coral from the Matmor Formation Image:Jurassic Calcarea Matmor Israel.jpg, Calcarea sponge and encrusting

crinoid Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...

from the Matmor Formation Image:MatmorScleractinian.JPG,

Scleractinia Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a ...

n coral from the Matmor Formation Image:Cymatonautilus.JPG, ''Paracenoceras'', a nautiloid from the Matmor Formation Image:Enallhelia 370 Callovian Israel.JPG, ''Enallhelia'', a scleractinian coral from the Matmor Formation Image:Fimbria CW265 2007.JPG, ''Fimbria'' sp.; a bivalve from the Matmor Formation Image:Amphiastrea Etallon 1859 Matmor Formation.JPG, ''Amphiastrea'' Etallon 1859; a scleractinian coral from the Matmor Formation Image:Axosmilia side 031815.jpg, ''Axosmilia'', a scleractinian coral from the Matmor Formation (Middle Jurassic) of southern Israel; side view Image:Axosmilia oral view 031815.jpg, ''Axosmilia'', a scleractinian coral from the Matmor Formation (Middle Jurassic) of southern Israel; oral view Image:MicrosolenaCW366.jpg, The scleractinian coral ''Microsolena'' from the Matmor Formation, Middle Jurassic, southern Israel Image:Epistreptophyllum Matmor CW366.jpg, ''Epistreptophyllum'', a scleractinian coral from the Matmor Formation (Middle Jurassic) of southern Israel; side view Image:Actinostreon Matmor Jurassic 171 173.jpg, ''Actinostreon'' spp. from the Matmor Formation (Middle Jurassic, Callovian) of Makhtesh Gadol, southern Israel Image:Mytilus (Falcimytilus) jurensis.jpg, ''Mytilus (Falcimytilus) jurensis'' from the Middle Jurassic (Callovian) Matmor Formation of Makhtesh Gadol, southern Israel

Stratigraphy

Gallery

References

Further reading