Vesicular Lava - Pentire Head ( S5 )

The Pillow Lavas in this area are highly Vesicular - seen as tiny holes in the surface of the rocks.
As Volcanic Magma nears the surface , pressure is reduced and gas dissolved in the magma is able to form vesicles (gas bubbles ).
The Lavas were originally Basalt but have been weakly altered during the Variscan Orogeny to meta- morphosed Basalts ( plagioclase-phyric alkali Basalts ).
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Top Pic - Some of the Pillow Lavas in this outcrop have eroded leaving their outline.
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Bottom Pic - a close up of the Vesicles in a Pillow Lava whose surface has eroded away.
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Pentire Head / The Rumps is between Polzeath and Port Quin in Section / Gallery 5
Ref:
4588.90
Date:
2017-03-27 00:00:00.0
Location:
SW 932 808
Photographer:

Vesicular Lava - Pentire Head ( S5 )

The Pillow Lavas in this area are highly Vesicular - seen as tiny holes in the surface of the rocks.
As Volcanic Magma nears the surface , pressure is reduced and gas dissolved in the magma is able to form vesicles (gas bubbles ).
The Lavas were originally Basalt but have been weakly altered during the Variscan Orogeny to meta- morphosed Basalts ( plagioclase-phyric alkali Basalts ).
-------------------
Top Pic - Some of the Pillow Lavas in this outcrop have eroded leaving their outline.
----------------
Bottom Pic - a close up of the Vesicles in a Pillow Lava whose surface has eroded away.
-----------------------------------------------
Pentire Head / The Rumps is between Polzeath and Port Quin in Section / Gallery 5
Ref:
4588.90
Date:
2017-03-27 00:00:00.0
Location:
SW 932 808
Photographer: