The Channeling (Microventing) Phenomenon in Young Marine Sediments

The objective of the present research is to explore the causes of microventing, a phenomenon generally occurring in cohesive sediments during their deposition and consolidation. Microvents are characterized by volcano-like formations, remnants of the expulsion of fluid and sediment along a vertical channel through the sediment layer. The size of these vent formations ranges from the order of millimeters to several centimeters, hence the term "microvent." Several causes proposed for microvents may be generally grouped as biological processes and mechanical processes. An example of a biological process is the production of subsurface gas due to organic decomposition; rising bubbles can produce microvents. The present study is concerned only with mechanical processes, which are hypothesized to be: A) Pressure fluctuations in pore fluid; B) Solids concentration perturbations near sediment—suspension interface; C) Gas expulsion by sediment compression. The overall scope of this investigation is to describe the microventing process in pure clay sediments and in young marine sediment deposits. Specific tasks of this project are: I) Identify whether microventing occurs in consolidation of kaolinite from a low initial concentration II) Identify the control parameter for microventing through different methods of detection III) Perform controlled tests to determine threshold of fluidization Incorporate this knowledge into a numerical code