slide1
Download
Skip this Video
Download Presentation
Homogenites - Unifites

Loading in 2 Seconds...

play fullscreen
1 / 18

Homogenites - Unifites - PowerPoint PPT Presentation


  • 52 Views
  • Uploaded on

Quaternary Volcanic Eruptions of the Santorini Island and Associated Gravity Flow Deposits in the Cretan Basin, South Aegean Sea. Efthymios K. Tripsanas, Aristomenis P. Karageorgis, Christos Anagnostou, Vasilis Lykousis, Dimitris Sakelariou

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Homogenites - Unifites' - zeki


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Quaternary Volcanic Eruptions of the Santorini Island and AssociatedGravity Flow Deposits in the Cretan Basin, South Aegean Sea

Efthymios K. Tripsanas, Aristomenis P. Karageorgis, Christos Anagnostou, Vasilis Lykousis, Dimitris Sakelariou

Hellenic Centre for Marine Research, Institute of Oceanography Anavyssos, Greece, [email protected]

homogenites unifites

Characteristics

  • Homogenous mud deposits (optical observations and X-ray radiographs)
  • Usually based by a thick (up to 0.5 m), massive to laminated sand layer
  • Couple of meters to several decameters thick
  • Transparent seismic packets that smooth out all existing morphology
  • Occurrence
  • Confined basins
  • Genessis
  • Related to catastrophic events, such as large sediment failures caused by earthquakes
  • Process
  • Segregation of high-energy turbidity currents (Cita and Aloisi, 2000)
  • Reflection of a high-energy turbidity current on the walls of a confined deep-water basin, with progressive confinement (Tripsanas et al., 2004)
  • An oscillatory movement of the whole water mass, initiated by a sudden bottom modification (sieche effect) (Beck et al., 2007)

Homogenites - Unifites

thick deposits of homogenites

Thick Deposits of Homogenites

These deposits have related to the Minoan volcanic eruption at 3.6 ka

Are we sure about that?

Several sand beds on top of the homogenites, and lack of a distinct and clear radiocarbon date

Anastasakis (2008)

volcanic eruptions of santorini island

Volcanic eruptions of Santorini Island

Caldera Collapse 4

Caldera Collapse 3

Caldera Collapse 2

Caldera Collapse 1

Heiken and McCoy (1984), Druitt et al. (1989)

pathways of pyroclastic and gravity flows

Pliocene/Quaternary

Pyroclastic Flows

Debris flows?

Messinian

N

S

Pathways of Pyroclastic and Gravity Flows

1.2 km

100 ms

or

75 m

pathways of pyroclastic and flows

W

E

1.2 km

Pathway for Santorini Pyroclastic Flows?

Pathways of Pyroclastic and Flows

100 ms

or

75 m

ash layers in cretan basin

Ash Layers in Cretan Basin

Y4 ash layer

~30-40 ka

Z2 ash layer

~3.6 ka

Y2 ash layer

~20 ka

slide13

?

Age Determination - Homogenites

Z2 ash layer

~3.6 ka

Y4 ash layer

~30-40 ka

Y2 ash layer

~20 ka

age determination homogenites

Age Determination - Homogenites

Z2 glass turbidite

~3.6 ka

Z2 glass turbidite

~3.6 ka

Y2 glass turbidite

~20 ka

Y2 glass turbidite

~20 ka

Homogenites

Homogenites

Homogenites

Y4 glass turbidite

~30-40 ka

Homogenites

Homogenites

22

13

volcanic eruptions of santorini island1

Volcanic eruptions of Santorini Island

Caldera Collapse 4

Caldera Collapse 3

Caldera Collapse 2

Caldera Collapse 1

Heiken and McCoy (1984), Druitt et al. (1989)

discussion

The homogenites formed shortly before the Y-4 ash layer, and probably was the Upper Scoriae 2 eruption phase that resulted in their formation

  • The thick uniform mud deposits in the homogenites require a process that would be able to erode, suspend, and transfer vast amounts of mud from the shelf and slope to the deep Cretan Basin
  • Origin
    • The production of large gravity flows, originating from the collapse of the dome
    • And/or
    • Underwater propagating pyroclastic flows have been observed in other areas (e.g. Soufriere Hills volcano, Montserrat, West Indies by Trofimovs et al., 2008)
  • The absence of uniform, thick mud deposits on top of the thin sand turbidites of the Minoan (Z2) and Cape Riva (Y2) volcanic eruptions suggests a different origin for their formation, most likely post-generated small-scale landslide events related to regional earthquakes

Discussion

discussion1

Discussion

  • Homogenites in Cretan Basin are related to catastrophic volcanic eruptions
  • Not all volcanic eruptions produce homogenites
  • Homogenites do not provide a full record of volcanic activity, but only of the most major eruptions
question statement

The Minoan Eruption at 3.6 ka resulted in the destruction of civilization, and is mentioned by many people as a disaster of biblical proportions

THIS ERUTION WAS NOT ONE OF THE LARGEST!!!

What if a homogenite producing eruption is going to occur in the near future?

Question - Statement

Thank you

ad