Skjaldbreiður

Definition

Skjaldbreiður is a type of shield volcano characterized by its broad, dome-like shape and gentle slopes formed by the eruption of low-viscosity basaltic lava. This volcanic structure is notable for its extensive lava flows that spread out over large areas, making it distinct from other volcanic forms. The term translates to 'broad shield' in Icelandic, reflecting its physical appearance and the way it builds up over time through repeated eruptions.

5 Must Know Facts For Your Next Test

1. Skjaldbreiður is primarily found in Iceland and is one of the most recognized shield volcanoes in the country due to its unique shape and formation.
2. This type of volcano typically produces relatively non-explosive eruptions because of the low viscosity of the basaltic lava it erupts.
3. The broad slopes of skjaldbreiður allow for the accumulation of large volumes of lava over time, leading to its distinctive dome-like structure.
4. Skjaldbreiður was formed during multiple eruptive episodes, which contributed to its expansive size and gentle topography.
5. Because of their shape and composition, skjaldbreiður volcanoes tend to have less violent eruptions compared to stratovolcanoes, resulting in fewer hazards for nearby populations.

Review Questions

• How does the structure of skjaldbreiður compare to that of a stratovolcano?
  • Skjaldbreiður has a broad, dome-like structure with gentle slopes, which contrasts sharply with the steep, conical shape typical of stratovolcanoes. While skjaldbreiður is built primarily from low-viscosity basaltic lava that flows easily across the landscape, stratovolcanoes are constructed from layers of more viscous lava and pyroclastic materials that lead to their steep profiles. This fundamental difference in shape reflects the types of eruptions each volcano experiences, with skjaldbreiður generally having less explosive activity than stratovolcanoes.
• What role does the viscosity of lava play in shaping the features of skjaldbreiður and influencing its eruptive behavior?
  • The low viscosity of basaltic lava plays a critical role in shaping skjaldbreiður by allowing lava to flow over great distances before cooling and solidifying. This characteristic results in the gentle slopes and broad profile that define shield volcanoes. In terms of eruptive behavior, lower viscosity means that gases can escape more easily during eruptions, leading to less explosive activity compared to more viscous lavas found in stratovolcanoes. Consequently, skjaldbreiður tends to produce non-explosive eruptions that create extensive lava flows instead of violent explosions.
• Evaluate how the formation processes and eruption styles of skjaldbreiður influence the surrounding ecosystems and human activity.
  • The formation processes and eruption styles of skjaldbreiður have significant implications for both ecosystems and human activity in their vicinity. The non-explosive eruptions produce large lava flows that can create new landforms but typically do not pose immediate threats to human settlements due to their gradual nature. This allows local ecosystems to adapt over time as new habitats are formed. Additionally, areas around skjaldbreiður may benefit from fertile volcanic soils resulting from weathering processes post-eruption, making them attractive for agriculture. However, any eruptions can still disrupt local communities temporarily, particularly if they coincide with population growth or urban development.

Related terms

Basalt: A dark, fine-grained volcanic rock that is commonly associated with shield volcanoes due to its low viscosity when molten, allowing for extensive lava flow.

Lava Flow: The movement of molten rock from a volcano, which can create various landforms depending on the viscosity of the lava and the landscape it travels over.

Volcanic Island Arc: A chain of volcanic islands formed as a result of tectonic plate interactions, often characterized by a series of stratovolcanoes and shield volcanoes.