Stratigraphy and paleoecology of some mesozoic sediments, Otamita Stream, Southland.
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Abstract:
A 4 km thick sequence of Triassic and Jurassic sediments (Murihiku Supergroup) are mapped over an area of 8 km2. The sequence is subdivided into twenty three lithologically based formations.
The nine formations of Griffin (1970) (Jurassic) could not be recognized with certainty in the area and five are redefined.
For the Triassic, seven new formations are formally introduced, and three are given new names.
A sedimentary facies model for the sequence is suggested and it is concluded that the sequence consists of possibly eight cycles of probably shallow shelf) depositional transgressions punctuated by erosive regressions (disconformities).
The faunas are studied in detail: twenty three new species and three new genera are recognized (mainly from the Trechmann Concretionary Siltstone, and mainly molluscs) and a possible lineage in the Pleurotomarids is suggested.
A detailed paleoecological study is made of the Trechmann Concretionary Siltstone: five con~unities are recognized and a shallow inshore shelf (10- 35 m) paleoenvironment is concluded, with at least one cycle of transgression and regression.
The nine formations of Griffin (1970) (Jurassic) could not be recognized with certainty in the area and five are redefined.
For the Triassic, seven new formations are formally introduced, and three are given new names.
A sedimentary facies model for the sequence is suggested and it is concluded that the sequence consists of possibly eight cycles of probably shallow shelf) depositional transgressions punctuated by erosive regressions (disconformities).
The faunas are studied in detail: twenty three new species and three new genera are recognized (mainly from the Trechmann Concretionary Siltstone, and mainly molluscs) and a possible lineage in the Pleurotomarids is suggested.
A detailed paleoecological study is made of the Trechmann Concretionary Siltstone: five con~unities are recognized and a shallow inshore shelf (10- 35 m) paleoenvironment is concluded, with at least one cycle of transgression and regression.
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141 leaves : illus. (part col.) chart, map (in pocket) ; 30 cm.
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1979Morton
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POLYGON ((168.670768936000059 -46.040939295999976,168.646961511000086 -46.035847643999944,168.647448236000059 -46.030675723999934,168.648432679000052 -46.020183605999932,168.653043079000099 -46.004927996999982,168.701054588000034 -46.006429124999954,168.698427650000099 -46.042093645999955,168.67392988000006 -46.041613702999939,168.670768936000059 -46.040939295999976))
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Citation
Morton, John George Godfrey, 1958-, “Stratigraphy and paleoecology of some mesozoic sediments, Otamita Stream, Southland.,” Otago Geology Theses, accessed April 23, 2025, https://theses.otagogeology.org.nz/items/show/123.