The Earth’s subsurface hosts enormous volumes of hydrocarbons, particularly methane, either trapped in the shallow sediments, sequestered as hydrates and permafrost, or naturally escaping trough cold seepage to enter the hydrosphere and atmosphere.
Cold seeps release hydrocarbons in all oceans and ultimately in the Earth’s atmosphere. These seeps interact physically, chemically, and biologically with the surrounding environment. These interactions, increasingly regarded as critical in the global carbon cycle, remain underestimated and poorly understood.
A greater effort is needed by integrating information at multi-temporal and multi-spatial scales. Evidences of past seepage, recorded by proxies such as methane-derived authigenic carbonates, hold large amount of time-integrated information about the processes governing seep dynamics.
This information must be assessed and compared to long-term observatory studies of hydrocarbon seeps currently active in a rapidly changing climate. Ultimately, past records and modern examples form the foundations to understand the mutual dependences between the global environment and seepage, and to develop robust models to forecast future scenarios.
A greater effort is needed by integrating information at multi-temporal and multi-spatial scales. Evidences of past seepage, recorded by proxies such as methane-derived authigenic carbonates, hold large amount of time-integrated information about the processes governing seep dynamics. This information must be assessed and compared to long-term observatory studies of hydrocarbon seeps currently active in a rapidly changing climate. Ultimately, past records and modern examples form the foundations to understand the mutual dependences between the global environment and seepage, and to develop robust models to forecast future scenarios.
We use a multidisciplinary and integrated approach to resolve the genesis and evolution of features associated with cold seepage such as methane-derived carbonates and mud volcanoes.
We explore the significance of cold seeps from local basins to the scale of the Earth system, to know more about the processes that govern methane release in the geological past and nowadays. Without knowing these processes more in detail, predictions for the future will always suffer a higher uncertainty.
Methane-Derived Authigenic Carbonates
Methane-derived authigenic carbonates are one of the main by-products of methane flow in the near-seafloor subsurface. We investigate their role as a record of past and present methane emission.
Despite the understanding of methane-derived carbonates increased in the last decade, the details of their formation remain poorly solved. Among everything, how the processes involved in their precipitation respond to variations of methane flux associated with changes of the environment? How can we better use the biogeochemical signatures recorded in the carbonates to interpret variations in fluid composition over time?
Mud volcanoes are hazards as their mud flows can destroy infrastructures. The Sidoarjo Mud Volcano in North Eastern Java, which suddenly erupted in 2006, within weeks submerged several villages with boiling mud, forcing thousands from their homes. Scientists extensively debated the formation of Sidoarjo and proposed contrasting trigger mechanisms for its genesis (here and here). This discussion is a perfect example of the large uncertainties still present in our understanding of the phenomenon.
We investigate the processes governing the birth and evolution of mud volcanoes, with particular attention to their interaction with, and influence on, the surrounding geological environment.
Mass Transport Deposits
Despite the Gulf of Mexico being one the most explored basins worldwide, the near-seabed and shallow subsurface of deep and ultra-deep water (> 1000m) are still poorly known. Only in the last 15 years the extensive use of AUV-borne mapping systems started to depict surficial morphology and shallow subsurface geology with adequate details and resolution. The main result is that these areas are active and dynamic. Particularly interesting in the Gulf of Mexico is to understand the genesis and architecture of Mass Transport Deposit (MTDs).
The internal structures and extents of the MTDs have been characterized in several areas of the Gulf of Mexico using hydrocarbon exploration 3D seismic data. However, these data resolution provides a good understanding only of the large MTDs and of the deformation history up to the base of Pleistocene. Therefore, the detailed characterization of smaller-scale deposits emplaced during the most recent time interval is missing. Using an analogy with classic sequence stratigraphy, we have a wealth of information about the low order structures but not about the high order systems
Tsunami and extreme waves sedimentology
Tsunamis are the most famous and destructive results of coastal earthquakes, in part because they can cause damage thousands of miles from the earthquake epicenter. Typically, two small local tsunamis occur each year throughout the world. Instead, major tsunamis are infrequent events that may hit the same portion of coastline with a recurrence time of centuries. Even on a tectonically active coastline, the most recent large tsunami may predate the written record (e.g. 1700 Cascadia).
Researchers have spent decades comparing the results of models of ancient tsunamis to the deposits of modern tsunamis. In the last three decades, geologists have been to most areas hit by tsunamis soon after the event (starting with 1992 Nicaragua), and in each case sedimentologists have collected data to help benchmark models of tsunami deposition. We still don’t know exactly what processes affect the tsunami sediments nor how much of the original deposit is returned to the ocean.
We focus on tsunami and storm sedimentation, in an effort not only to understand how to identify ancient catastrophes from their deposits but to determine how large those catastrophes were and the processes acting on their sediments after deposition.
Tuscaloosa Marine Shale
The Gulf of Mexico experienced various anoxic events during the Cretaceous that are now preserved in the sedimentary record as organic-rich black shales. One example is within the Tuscaloosa Group, which comprises a complete second-order depositional sequence with the Cenomanian-Turoninan Tuscaloosa Marine Shale (TMS) corresponding to the inundated phase after transgression.
Although the economic potential of the TMS has been extensively evaluated by the O&G industry, TMS\’ sedimentology and stratigraphy remain relatively under-investigated at the basin scale. While several studies developed a depositional model for the TMS, most relied solely on well-log data. We work on expanding our knowledge of TMS deposition by analyzing recovered cores.