Rhone Deep-Sea Fan: A review

The Rhone Fan is a large Plio-Pleistocene turbidite deposit in the western Mediterranean Sea. The fan is fed from the broad Rhone River delta, but only one canyon, the Petit-Rhone, has fed most of the major turbidite depositional sequences that have been mapped. Slumping of sediment from intercanyon areas on the delta slope also has provided much sediment for the fan. The lack of Recent turbidite deposition on the fan suggests that turbidite sedimentation dominates during glacial low stands of sea level, building major leveed valley sequences, while surficial slumping of the valley levee deposits and pelagic sedimentation seem to mark high stands of sea level during interglacial periods.     

The Ebro Deep-Sea Fan system

The Ebro Fan System consists of en echelon channel-levee complexes, 50×20 km in area and 200-m thick. A few strong reflectors in a generally transparent seismic facies identify the sand-rich channel floors and levee crests. Numerous continuous acoustic reflectors characterize overbank turbidites and hemipelagites that blanket abandoned channel-levee complexes. The interlobe areas between channel complexes fill with homogeneous mud and sand from mass flow and overbank deposition; these exhibit a transparent seismic character. The steep continental rise and sediment “drainage” of Valencia Trough at the end of the channel-levee complexes prevent the development of distributary channels and midfan lobe deposits. Margin setting represents fan and/or source area     

The Ebro Deep-Sea Fan system

The Ebro Fan System consists of en echelon channel-levee complexes, 50×20 km in area and 200-m thick. A few strong reflectors in a generally transparent seismic facies identify the sand-rich channel floors and levee crests. Numerous continuous acoustic reflectors characterize overbank turbidites and hemipelagites that blanket abandoned channel-levee complexes. The interlobe areas between channel complexes fill with homogeneous mud and sand from mass flow and overbank deposition; these exhibit a transparent seismic character. The steep continental rise and sediment “drainage” of Valencia Trough at the end of the channel-levee complexes prevent the development of distributary channels and midfan lobe deposits.     

The Deep-Sea Fan deposits of the miocene Marnoso-Arenacea formation,northern Apennines

Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored (choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis on “inner” or “autocyclic” mechanisms.     

The Deep-Sea Fan deposits of the miocene Marnoso-arenacea formation, northern Apennines

Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored (choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis on “inner” or “autocyclic” mechanisms. Margin setting represents fan and/or source area     

Morphology,sedimentation processes,and growth pattern of the Amazon Deep-Sea Fan

The Amazon Deep-Sea Fan began to form in the Early Miocene and is characterized by a highly meandering distributary channel system. On the middle fan, these leveed channels coalesce to form two broad levee complexes. Older, now buried levee complexes are also observed within the fan. These levee complexes grow through channel migration, branching, and avulsion. Probably only one or two channels are active at any given time. Sediments reach the fan only during glacio-eustatic low stands of sea level. Coarse sediments largely by-pass the upper and middle fan via the channels and are deposited on the lower fan.     

Environment and Deep-Sea Mining: A Perspective

Abstract

As the quest for deep-sea mineral resources is gaining momentum, environment and ocean mining have become important aspects of study. Because many of these deposits occur in international waters, the concern for environmental conservation in view of the effects of deep-sea mining is resulting in these effects being studied in different oceans, and efforts to develop regulations governing this exploitation are also underway at national and international levels. The impact assessment of deep-sea mining needs to encompass a variety of subjects, including environmental, socioeconomic, technological, and legal aspects. At the same time, effects of in situ environmental conditions on mining activities also need to be considered for effecient performance by the mining system. Differences in the degree of impact have been noticed during the mining simulation experiments by different investigating agencies. Therefore, interparameter comparisons, standardization of methods, and improvement in mining design are important considerations for proper utilization of resources, conservation of environment, and cost efficiency of the mining operations.     

Environment and Deep-Sea Mining: A Perspective

As the quest for deep-sea mineral resources is gaining momentum, environment and ocean mining have become important aspects of study. Because many of these deposits occur in international waters, the concern for environmental conservation in view of the effects of deep-sea mining is resulting in these effects being studied in different oceans, and efforts to develop regulations governing this exploitation are also underway at national and international levels. The impact assessment of deep-sea mining needs to encompass a variety of subjects, including environmental, socioeconomic, technological, and legal aspects. At the same time, effects of in situ environmental conditions on mining activities also need to be considered for effecient performance by the mining system. Differences in the degree of impact have been noticed during the mining simulation experiments by different investigating agencies. Therefore, interparameter comparisons, standardization of methods, and improvement in mining design are important considerations for proper utilization of resources, conservation of environment, and cost efficiency of the mining operations.     

Morphology, sedimentation processes, and growth pattern of the Amazon Deep-Sea Fan

The Amazon Deep-Sea Fan began to form in the Early Miocene and is characterized by a highly meandering distributary channel system. On the middle fan, these leveed channels coalesce to form two broad levee complexes. Older, now buried levee complexes are also observed within the fan. These levee complexes grow through channel migration, branching, and avulsion. Probably only one or two channels are active at any given time. Sediments reach the fan only during glacio-eustatic low stands of sea level. Coarse sediments largely by-pass the upper and middle fan via the channels and are deposited on the lower fan. Margin setting represents fan and/or source area     

Acoustics-Based Autonomous Docking for A Deep-Sea Resident ROV

This paper presents autonomous docking of an inhouse built resident Remotely Operated Vehicle(ROV), called Rover ROV, through acoustic guided techniques. A novel cage-type docking station has been developed. The docking station can be placed on a deep-sea lander, taking the Rover ROV to the seafloor. Instead of using visionbased pose estimation techniques and expensive navigation sensors, the Rover ROV docking adopts an ultra-short baseline(USBL) and low-cost inertial sensors to build an adaptiv...     

Path Following Control of A Deep-Sea Manned Submersible Based upon NTSM

In this paper, a robust path following control law is proposed for a deep-sea manned submersible maneuvering along a predeterminated path. Developed in China, the submersible is underactuated in the horizontal plane in that it is actuated by two perpendicular thrusts in this plane. The advanced non-singular terminal sliding mode （NTSM） is implemented for the design of the path following controller, which can ensure the convergence of the motion system in finite time and improve its robustness against parametric uncertainties and environmental disturbances. In the process of controller design, the close-loop stability is considered and proved by Lyapunov＇ s stability theory. With the experimental data, numerical simulations are provided to verify the control law for path following of the deep-sea manned submersible.     

Experimental study of the Rhone plume. Part I: physics and dynamics

The complicated dynamic processes occurring when fluvial waters mix with marine waters control the nature and the fluxes of materials exported by rivers to the sea. Understanding these processes is of primary importance in evaluating budgets. In wide-open estuarine situations these processes take place under the influence of an intense turbulence induced by tides. Conversely, the Rhone waters spread into the Mediterranean Sea in the form of an easily distinguishable buoyant plume often extending far offshore from the mouth of the river. The aim of this study is to describe the dynamic and hydrological fields on the basis of eulerian VHF radar mapping of surface currents coupled with lagrangian in situ physical or geochemical measurements. This paper focuses mainly on physical processes. Data analysis provides an insight into the typical scales of variability of the phenomena, either vertically or horizontally. It is shown that morphological fluctuations can occur (mainly in orientation and offshore extent) according to wind and outflow forcing conditions, and that the vertical structure variations can range from an almost unaltered two-layer distribution to an evolving and deepening mixed layer situation, or even to a more complex superimposed multi-layered structure. The simultaneous examination of radar maps and lagrangian drifter tracking allows the main dynamic tendencies of the Rhone plume to be sketched out.     

Deep-Sea Nodules and Co-rich Mn Crusts

The mining of deep-sea manganese nodules has been a topic of interest since J.L. Mero undertook his preliminary studies in the 1960s to evaluate the prospects for mining deep-sea nodules. Despite the great deal of investment in deep-sea mining over more than 40 years, there has still been no successful attempt to mine the deep-sea nodules on a commercial scale. One of the major problems is that the nodules cannot be brought to the surface with the necessary amounts of recoverable nickel, cobalt and zinc to warrant the initial high investment necessary for this operation. It therefore appears that in the short term, deep-sea manganese and Co-rich Mn crusts will not be mined on a commercial scale in the foreseeable future. Nonetheless, investigations of deep-sea mineral deposits by a number of nations will continue and enable us to understand the deep-sea environment in increasing detail, which is necessary in view of the great extent of the deep oceans which cover an area of about 66% of the Earth's surface.     

Accumulator-Based Deep-Sea Microbe Gastight Sampling Technique

1.IntroductionPlenty of microbes exist in deep sea(Jiang,2000).They can survive and propagate under theconditions of extraordinary cold or heat and high pressure(Liu,2001).Studies on deep-sea microbesshowthat they have the function of decomposing petroleu…     

深海声学释放器释放过程的动力学分析

深海释放器是海洋观测仪器、海洋工程中关键设备。研究考虑海流、释放器部件碰撞等因素的深海释放器释放过程的动力学情况,采用多体动力方法建立某深海释放机构的动力学模型,模拟释放机构的释放过程中各构件的运动情况和运动轨迹,计算释放机构在释放过程各组成构件的运动参数,该方法可以用于模拟深海释放器释放过程状况,分析释放器失效的原因和指导释放机构的设计。     

大深度声遥测触底指示仪测高计换能器的研制

本文介绍利用表观弹性法,设计纵向振动与径向振动相耦合的朗芝万型换能器,该换能器用于大深度声遥测触底指示仪上,实验表明,理论计算值与实验值相符合,计算方法简单、方便。     

LVP Modeling and Dynamic Characteristics Prediction of A Hydraulic Power Unit in Deep-Sea

A hydraulic power unit (HPU) is the driving “heart” of deep-sea working equipment. It is critical to predict its dynamic performances in deep-water before being immerged in the seawater, while the experimental tests by simulating deep-sea environment have many disadvantages, such as expensive cost, long test cycles, and difficult to achieve low-temperature simulation, which is only used as a supplementary means for confirmatory experiment. This paper proposes a novel theoretical approach based on the linear varying parameters (LVP) modeling to foresee the dynamic performances of the driving unit. Firstly, based on the varying environment features, dynamic expressions of the compressibility and viscosity of hydraulic oil are derived to reveal the fluid performances changing. Secondly, models of hydraulic system and electrical system are accomplished respectively through studying the control process and energy transfer, and then LVP models of the pressure and flow rate control is obtained through the electro-hydraulic models integration. Thirdly, dynamic characteristics of HPU are obtained by the model simulating within bounded closed sets of varying parameters. Finally, the developed HPU is tested in a deep-sea imitating hull, and the experimental results are well consistent with the theoretical analysis outcomes, which clearly declare that the LVP modeling is a rational way to foresee dynamic performances of HPU. The research approach and model analysis results can be applied to the predictions of working properties and product designs for other deep-sea hydraulic pump.     

Deep-Sea Impact Experiments and their Future Requirements

In recent years, several experiments to assess the potential impacts due to deep-sea mining in the Pacific as well as the Indian Oceans have indicated the immediate changes and restoration patterns of environmental conditions in the marine ecosystem. The large volume of sediment(~ 500 × 10⁷ m³ per year) estimated to be resuspended would be the major influencing factor in environmental impact in the mining area, leading to changes in availability of certain nutrients and composition of biomass, followed by gradual restoration. Important results have been obtained from these experiments, but in order to have a better understanding of the impacts and restoration processes, it will be necessary to improvise future experiments to resemble actual deep-sea mining in terms of scale and methodology.