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 (, ''lit.'' The Big Crater) or simply Makhtesh HaGadol or Makhtesh Gadol, 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 surr ...

in southern Israel. The Matmor Formation contains fossils from a

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

equatorial shallow marine environment.

Bivalves Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

echinoderm An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as ...

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

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

of the Matmor Formation consists of alternating layers of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

and

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

(Hirsch and Roded, 1996).

Stratigraphy

The Iraq Petroleum Company 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 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

, Divesian, Argovian, Sequanim biostratigraphic 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 (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,

Marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

s and

s of the Matmor Formation exposed near the center of Makhtesh Gadol Image:GastrochaenolitesMatmor.jpg, ''

Gastrochaenolites ''Gastrochaenolites'' is a trace fossil formed as a clavate (club-shaped) boring in a hard substrate such as a shell, rock or carbonate hardground. The aperture of the boring is narrower than the main chamber and may be circular, oval, or dumb-be ...

'' boring in a coral from the Matmor Formation Image:Jurassic Calcarea Matmor Israel.jpg, Calcarea sponge and encrusting

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

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