Terrigenous indicators sediments

The fourth example from the distal Bengal Fan (Hiibscher et al. 1997) was recorded during RV Sonne craise S0125 and displays terrigenous features and sediments (Fig. 2.25d). Active and older abandoned channel levee systems are characterized by a diffuse reflection pattern which indicates sediments of coarse-grained turbidites. Signal penetration in such environments is rather low and reaches about 30 - 40 m. 

Comparison of the depositional fluxes shows that diatoms were the most important particle component transporting P to the sediment surface, accounting for 50-55% of the flux (Table II). Terrigenous material and calcite were also important transport vectors. Deposition varied markedly with season, as shown by the time series plot of the major particle components (Figure 13). The total P flux calculated by using the particle components model agreed with the flux measured by sediment traps (157-227 versus 185 mg/m2). The close agreement indicated that the major particle vectors were represented and associated P concentrations were accurately quantified. 

Prahl, F.G, Haynes, J.M., and Xie, T.M. (1992) Diploptene an indicator of terrigenous organic carbon in Washington coastal sediments. Lirnnol. Oceanogr. 37, 1290-1300. 

With eustatic sea level transgression and flooding of continental lowlands, transport of terrigenous organic matter into the North American basin may have increased. Analyses of Upper Cretaceous sediments from DSDP Site 6O3B, lower continental rise east of Cape Hatteras, indicate that, the organic matter was continentally derived. d C values of -23.5 to 27.1°/oo, C/N ratios of 32 to 72, and lipid class maxima of unbound alkanes (C-. and Cp-), unbound fatty acids (C and C2g) and bound fatty acids (C-g. 

As the acoustic properties of water-saturated sediments are strongly controlled by the amount and distribution of pore space, cross plots of P-wave velocity and attenuation coefficient versus porosity clearly indicate the different bulk and elastic properties of terrigenous and biogenic sediments and can thus be used for an acoustic classification of the lithology. Additional S-wave velocities (and attenuation coefficients) and elastic moduli estimated by least-square inversion specify the amount of bulk and shear moduli which contribute to the P-wave velocity (Breitzke 2000). 

Organic matter in sea surface sediments was mainly terrigenous and biogenous. So the ph3doplankton biomass impacting on organic matter in the water column and on the PCBs distribution in the surface sediments of the study area was discussed in detail as follows. Chlorophyll a concentrations and phytoplankton cell abundance in seawater were commonly used as indicators of... 

Turbidite samples from Sites 950, 951 and 952 (ODP Leg 157) on the MAP have between 0.75 and 1.68 wt% TOC and C/N ratios near 10. Rock Eval pyrolysis data indicate a fair source rock and immature sediments (Schmincke et al, 1995). The overall organic geochemical shipboard data indicate a predominantly marine origin of the OM (Schmincke et al, 1995), but including a terrigenous component. 

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