Showing papers by "Wolfgang H Berger published in 1986"
TL;DR: The carbon isotope signal in deep-sea sediments reflects a mix of global changes in the rates of exchange of the ocean's carbon reservoir with biosphere, soil, and sediments, global and regional changes in surface water productivity, internal shifts in water-mass structure and circulation, and organism-specific fractionation effects due to changes in micro-habitat and/or ontogenic fractionation as discussed by the authors.
Abstract: The carbon isotope signal in deep-sea sediments reflects a mix of (1) global changes in the rates of exchange of the ocean's carbon reservoir with biosphere, soil, and sediments, (2) global and regional changes in surface water productivity, (3) internal shifts in water-mass structure and circulation (basin-basin fractionation, oxygen minimum development), and (4) organism-specific fractionation effects due to changes in micro-habitat and/or ontogenic fractionation (»vital effects«). Additional complications arise from differential preservation. It is impossible to entirely isolate these various factors. As a rule of thumb, long period signals that are parallel for planktonic and benthic data reflect external (global) fractionation patterns, whilst short-period signals are more likely tied to internal patterns (water-mass fractionation). The various approaches to interpretation are illustrated with three case studies: the Glacial-Holocene transition, the Messinian Carbon Shift, and the Miocene Monterey Excursion.
261 citations
TL;DR: In this paper, a sporadic shutdown of North Atlantic deep water (NADW) was detected in deep-sea carbonates with normal (low) sedimentation rates, and the possibility arises that relatively short-lived events (∼1,000−2,000 yr) in deep circulation can be mapped over large areas of the sea floor, despite the detrimental effects of bioturbation on signal resolution.
Abstract: Pulsations in the production of North Atlantic deep water (NADW) have been implicated in generating drastic climatic fluctuations during the Glacial–Holocene (G/H) transition1–3. The stable isotope record of benthic foraminifera in high-resolution cores from the Norwegian Sea suggests that such pulsations did occur4. Although the question of exact timing (and mechanism) is still open there is little doubt that NADW pulsations were important in climatic history because the rate of NADW production influences the rate of advection of heat to the northern North Atlantic5. Here we report that a sporadic shutdown of NADW may be recognizable in deep-sea carbonates with normal (low) sedimentation rates. Hence the possibility arises that relatively short-lived events (∼1,000–2,000 yr) in deep circulation can be mapped over large areas of the sea floor, despite the detrimental effects of bioturbation on signal resolution.
46 citations
TL;DR: Gumbel's hypothesis was essentially forgotten until it was recreated in the middle of this century as discussed by the authors, which was strongly influenced by his experience with metalbearing hot springs on land and his convictions regarding mechanisms of ore formation in general.
Abstract: The Bavarian geologist Gumbel (Figure 1) was the first German scientist to study manganese nodules in some detail (1878). Gumbel studied nodules from expeditions of both the Gazelle and the Challenger, which operated in the North Pacific at the same time (1875), and he gave detailed descriptions. He generated a remarkable range of ideas to explain the origin of the nodules and concluded that most or all of the iron and manganese in deep ocean ferromanganese concretions have their source in submarine vents that emit gas and hot water. It seems that his choice between different hypotheses was strongly influenced by his experience with metal-bearing hot springs on land and his convictions regarding mechanisms of ore formation in general. In any case, contemporary experts did not find his reasoning compelling. Gumbel's hypothesis was essentially forgotten until it was recreated in the middle of this century.
2 citations