Abstract
Global sea-level fluctuated markedly during the early Silurian,
probably as a result of the waxing
and waning of ice-sheets in the South American portion of Gondwana.
The highest sea-levels of the Silurian
are recorded by the Telychian upper crispus–lower griestoniensis
and spiralis–lower lapworthi biozones.
Other highstands occurred in the early Aeronian, during the
convolutus Zone (mid Aeronian), guerichi Zone
and late turriculatus Zone (early Telychian), and early
Sheinwoodian. Low sea-levels characterized much of
the argenteus and sedgwickii zones (Aeronian), the utilis
Subzone (late guerichi–early turriculatus zones,
early Telychian), the late Telychian (commencing in the mid
lapworthi Zone) and, after a period of apparently
only small amplitude sea-level fluctuations in the late
Sheinwoodian and earliest Homerian, the mid–late
Homerian, in particular the early nassa Zone. Facies (and
faunal) changes in the Lower Silurian do not support
the P and S model of Jeppsson and others, but are consistent with
the sea-level changes proposed herein.
Mid Telychian marine red beds appear to have been deposited
during a minor sea-level fall immediately after
a period of very high sea-levels, rather than during a transgressive
episode as previously suggested.
Comparison of the sea-level curve presented herein with those
constructed in the past is hampered by the lack
of precision currently possible in the correlation of early Silurian
deep water (graptolitic) and shallow water
(shelly) sequences. Improving the precision of this correlation
should be a priority for future research.
Publisher
Cambridge University Press (CUP)
Cited by
199 articles.
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