A stepwise extinction during the Mulde Event in the Homerian (Wenlock, Silurian) has been suggested for hemipelagic
fauna such as graptolites and conodonts (Jaeger 1991; Jeppsson 1993; Kaljo et al.
1988, Sulfide formation and hydrothermal alteration of hemipelagic
sediment in Middle Valley, northern Juan de Fuca Ridge: Canadian Mineralogist, v.
ABSTRACT: Mid- to outer shelf (= offshore) marine deposits of hemipelagic dark-gray mudstone comprising the Mahantango Formation (Middle Devonian), Pike County, Pennsylvania, have yielded an assemblage of trace fossils.
1996) interpret the mudstones of Facies Association 1 as that of hemipelagic deposits formed in an open marine setting (= offshore of MacEachern et al.
The Monterey Formation consists of siliceous hemipelagic
shale deposited at bathyal depth (Pisciotto and Garrison 1981), whereas the Puente Formation consists of more terrigenous sediments derived from the southeastern San Gabriel Mountains deposited as turbidites on submarine fans at bathyal depths (Critelli et al.
These sediments occur between the hemipelagic
organic-rich muds on the continental margin and carbonate sediments on the shallow shelf plateau--North Estonian Confacies Belt.
Detailed stratigraphic work in the Shimanto belt of Japan, for example, showed an orderly sequence before disruption: oceanic basement (basalts), pelagic sediments, hemipelagic
sediments with silicic tephras and muddy turbidites, and coarser grained turbidites, basically similar to that found in the Nankai Trough.
It is overlain conformably by condensed hemipelagic
, largely anoxic early Silurian black shale.
If the sedimentation rate increases, the red colour disappears and sediments turn grey, as in the hemipelagic
hemipelagic muds, which record continental erosion and runoff in their flux data.
The hemipelagic muds that may extend many hundreds to a thousand kilometers offshore are one of the last major unknowns of the several kinds of deep sea sediment.
Leg 146 recovered advanced piston cores from a basin in the California borderland that is characterized by a very high deposition rate of hemipelagic sediment.