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. Cores from these kinds of settings will play an increasingly important role as we turn our attention to climatic and environmental changes on short oceanic or societal time scales.
Since the early days of the ocean drilling programs, an important objective has been to provide the means to decipher the record of terrigenous material in pelagic and hemipelagic sediment accumulations.
Prior to the evolution of Cretaceous planktonic foraminiferal and subsequent paleoceanographic reconstruction, the hemipelagic sediments
of the Kawagarh Formation were put into a reliable time frame using the planktonic foraminiferal biostratigraphy.
Detailed inspection of the "productivity-dominated" style of hemipelagic sediments shows, that relative sealevel changes are not necessary to explain variations in foraminiferal abundances and cyclic variations in lithology.
In the southern areas, like the Basque-Cantabrian Basin and the W-Tethys, foraminiferal numbers from Cenomanian hemipelagic sediments suggest rather low primary export productivity (Grafe and Wendler, 2003, fig.
The hemipelagic sediments
are characterized by higher U concentrations due to higher contents of organic matter (Patino et al., 2000).
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.
This study is focused on sedimentology, palynofacies and biostratigraphy of the pelagic to hemipelagic sediments
of the Mughal Kot Formation, Rakhi Gorge Section, Sulaiman Range, Pakistan.
abundant hemipelagic sediments and rare shallow- marine sediment than the calcareous sediment on the Indian subcontinent to the south.
Their associations with hemipelagic sediments show that alkaline rocks were erupted in a hemipelagic environment.