//
you're reading...

Geology

First evidence of deep explosive volcanic activity at the Marsili Seamount

Paper: Iezzi, G., Caso, C., Ventura, G., Vallefuoco, M., Cavallo, A., Behrens, H., Mollo, S., Paltrinieri, D., Signanini, P., Vetere, F., 2014. First documented deep submarine explosive eruptions at the Marsili Seamount (Tyrrhenian Sea, Italy): A case of historical volcanism in the Mediterranean Sea. Gondwana Research 25: 764-774.

Introduction

In this study, Iezzi et al. document for the first time the occurrence of two tephras found in a gravity core collected on the Marsili Seamount, located between mainland Italy and Sicily. As defined by the USGS, tephra is a general term for fragments of volcanic rock and lava regardless of size that are blasted into the air by explosions, or carried upward by hot gases in eruption columns or lava fountains. The significance of the study is that it puts new, unexpected constraints on the age and type of activity of submarine volcanoes in the Mediterranean area and the hazard implications.

Findings

The Marsili Seamount is the about 3.2km tall with a 70km by 30km width, making it the largest volcanic complex in the Mediterranean area and Europe. It has long been thought the seamount formed from effusive lava flows (a non-explosive eruption with lava acting like a thick, sticky liquid) between 1 and 0.1 Ma. By analyzing the tephra deposits found in a core taken from the seamount, Iezzi et al. have concluded that the effusive flow model and age constraints are incorrect. Instead, the tephras are a result of explosive submarine volcanic activity that occurred only 3 thousand years before present time. This is the first evidence of explosive volcanic activity at significant depth (500-800 meters below sea level) found in the Mediterranean.

Location of gravity core on the Marsili Seamount, between Sicily and mainland Italy.

Location of gravity core on the Marsili Seamount, between Sicily and mainland Italy.

While some of the initial evidence suggests a provenance of the ashes from nearby subaerial Mt. Etna or Pantelleria, these ashes are ultimately excluded from those sources because they lack the Na-alkaline affinity.  Meaning, when chemical composition of the glass in the ash is analyzed, those from Marsili have less elemental sodium than others nearby.  The determined chemical composition can be used like a finger print for glass origin. Other regional volcanoes are similarly excluded as the tephra source for inadequate timing or the wrong rock type. In addition, morphological and stratigraphic evidence further supports submarine origin.

Analysis of the tephra supports the explosive submarine volcanic model, however it would help to bolster Iezzi’s case if the data set included more than one gravity core.  The team does acknowledge the lack of deposits in the proximal bathyal plains, but suggests this implies that the two eruptive events must have been low energy and did not produce enough material to travel far. Further expeditions in the region should consider adding to the data set.

Significance

Because of known seismicity and active hydrothermal degassing in the region, this study means that the still active Marsili Seamount could potentially erupt explosively in our time. The seamount should continue to be monitored closely and the related hazards should be evaluated for nearby communities.

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 13 hours ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 1 week ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 2 weeks ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 3 weeks ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 1 month ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 3 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 3 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 4 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 4 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 5 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 5 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 6 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 6 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
  • by oceanbites 7 months ago
    Feeling a bit flattened by the week? So are these summer flounder larvae. Fun fact: flounder larvae start out with their eyes set like normal fish, but as they grow one of their eyes migrates to meet the other and
  • by oceanbites 7 months ago
    Have you seen a remote working setup like this? This is a photo from one of our Oceanbites team members Anne Hartwell. “A view from inside the control can of an underwater robot we used to explore the deep parts
  • by oceanbites 8 months ago
    Today is the day of  #shutdownacademia  and  #shutdownstem  and many of us at the Oceanbites team are taking the day to plan solid actions for how we can make our organization and the institutions we work at a better place
WP2Social Auto Publish Powered By : XYZScripts.com