SINGH_C_Volcanoes_Tristan da Cunha Project Week 2
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GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
Volcanoes
a.
Answer the following questions. Cite all your sources in full APA citation format.
i.
Discuss the ways in which volcanism is a constructive process from a geological perspective.
Volcanism is a natural process on the Earth that builds and expands land. The study of volcanic landforms is essential for understanding how they are formed, change over time, and how they are affected by things like earthquakes and eruptions. It helps us understand their significance and impact on the environment. This knowledge helps us better understand how the Earth's rocks and landforms change over time (Thouret, 1999).
ii.
State where most volcanic hotspots are located
Many underwater areas have lots of volcanic hotspots. Some places with many volcanoes are Hawaii, Réunion, Yellowstone, Galápagos, and Iceland. These areas are usually linked to volcanoes that form when tectonic plates interact with hot material rising from the Earth's mantle (Libretexts, 2022).
Here are some examples of hotspot locations
Hawaiian-Emperor seamount chain (Hawaii hotspot)
Louisville seamount chain (Louisville hotspot)
Walvis Ridge (Gough and Tristan hotspot)
Kodiak–Bowie Seamount chain (Bowie hotspot)
Cobb-Eickelberg Seamount chain (Cobb hotspot)
New England Seamount chain (New England hotspot)
Anahim Volcanic Belt (Anahim hotspot)
GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
Mackenzie dike swarm (Mackenzie hotspot)
Great Meteor hotspot track (New England hotspot)
St. Helena Seamount Chain – Cameroon Volcanic Line (Saint Helena hotspot)
Southern Mascarene Plateau–Chagos-Maldives-Laccadive Ridge (Réunion hotspot)
Ninety East Ridge (Kerguelen hotspot)
Tuamotu–Line Island chain (Easter hotspot)
Austral–Gilbert–Marshall chain (Macdonald hotspot)
Juan Fernández Ridge (Juan Fernández hotspot) (Libretexts, 2022).
iii.
Describe the four basic types of volcanoes:
a.
Cinder Cones:
Cinder cones are the easiest kind of volcano. They look like a round or oval-shaped hill made from pieces of hardened lava. The lava is thrown out of one opening. The tops of the mountains are shaped like bowls and don't usually go more than a thousand feet higher than the land around them. The Parícutin Volcano in Mexico is a type of volcano called a cinder cone (USGS).
b.
Composite Volcanoes:
Composite volcanoes, also called stratovolcanoes, are tall and
symmetrical mountains made up of layers of lava, ash, rocks, and other materials. They can go up to 8,000 feet above where they start and have one main opening or a bunch of openings close together. Michael in Italy are two famous mountains that many people want to visit. Mount Fuji is located in Japan, and Mount St. Michael is
GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
located in Italy. They are well-known because they are tall and beautiful natural landmarks. People are often interested in going to these mountains to hike, take pictures, and enjoy the scenic views. Volcanoes in the United States called Helens are
types of volcanoes made of different materials (USGS).
c.
Shield Volcanoes:
Shield volcanoes are made chiefly of lava that flows easily and spreads long distances. It creates a wide, gently sloping shape resembling a warrior's shield. They are usually made of a type of lava called basalt, and they are massive volcanoes. Mauna Loa in Hawaii is the most giant active volcano with a flat, wide shape (USGS).
d.
Lava Domes:
Lava domes are created when small, thick masses of lava gather on and
around a volcano's opening. They get more significant from the inside and can make rough lumps, spikes, or minor, steep hills made of lava. Lava domes are usually seen inside craters or on the sides of enormous volcanoes that combine different materials. Some examples are Mont Pelée in Martinique and Lassen Peak in California (USGS).
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GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
References
Libretexts. (2022, May 6). 5.16: Hot spots
. Geosciences LibreTexts. https://geo.libretexts.org/Bookshelves/Geology/Fundamentals_of_Geology_(Schulte)/
05%3A_Plate_Tectonics/5.16%3A_Hot_Spots Thouret, J.-C. (1999). Volcanic geomorphology—an overview. Earth-Science Reviews
, 47
(1–2), 95–131. https://doi.org/10.1016/s0012-8252(99)00014-8
USGS. (n.d.). Principal Types of Volcanoes
. Volcanoes: Principal types of volcanoes. https://pubs.usgs.gov/gip/volc/types.html#:~:text=Geologists%20generally%20group
%20volcanoes%20into,shield%20volcanoes%2C%20and%20lava%20domes.
GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
Tristan da Cunha
Tristan da Cunha, an isolated volcanic island in the southern Atlantic Ocean, has a distinctive geographical position with coordinates of roughly 37.092°S latitude and 12.28°W longitude. The island, which is about 13 kilometers wide, is a shield volcano, a geological feature distinguished by its broad, gentle slopes. Tristan da Cunha, located approximately 500 kilometers east of the Mid-Atlantic Ridge and south of large cities like Buenos Aires and Cape Town, is a tribute to nature's beauty amid solitude. Despite its apparent tranquility, the island has
a volcanic past, with its most recent recorded eruption occurring between 1961 and 1962, illustrating the dynamic forces at work underneath its calm surface (
Global volcanism program: Tristan da Cunha, n
.d.).
Tristan da Cunha is a faraway, volcanic island in the South Atlantic Ocean. Most of the island is made up of basaltic materials. Basalt, including picro-basalt, is the primary type of rock found in this volcanic area. These rocks have a low to medium amount of silica content, ranging from 45% to 55%. These rocks are usually smooth and dark in color. They have minerals like plagioclase feldspar, pyroxenes, and olivine. However, the island also has rocks that are a little more complicated regarding their geological history. These rocks have names like trachybasalt, trachyandesite, and basaltic trachyandesite. They show that there were different times when volcanoes were active on the island, and they had different amounts of a substance called silica. Moreover, advanced rocks such as trachyte and trachydacite, which have more silica (around 65-
70%), suggest there can be more explosive eruptions. The small amount of phonolite indicates the possibility of volcanic events that are very explosive. The different types of rocks and materials from volcanoes have affected how the island looks and have created its unique features
(
Global volcanism program: Tristan da Cunha, n
.d.).
GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
Tristan da Cunha, a distant and dynamic stratovolcano, is a tribute to nature's incredible forces. This volcanic island rose from beneath the surface of the ocean around 3 million years ago, building a massive 48-kilometer-wide cone that peaks to a stunning 5,500 meters above sea level. The renowned Queen Mary's Peak, which rises 2,060 meters above the ocean's surface, overlooks a shaped like a crater lake, providing a stunning scene formed by millennia of volcanic
processes. This geological wonder is located approximately 400 kilometers east of the Mid-
Atlantic Ridge, which is situated above a magma hot zone (
The Tristan da Cunha Volcano
2019).
A mix of gentle and violent eruptions characterizes the volcanic activity on Tristan da Cunha. Explosive volcanoes produce a lot of lava that spreads like a sheet and gradually makes the land bigger. In comparison, powerful volcanic explosions, caused by magma that has a lot of gas, create volcanic ash and rocks with holes, like the pumice we have seen recently. These unique rocks, called "floating stones," have lots of empty spaces and openings. This shows how the volcanic processes on the island are very explosive (
The Tristan da Cunha Volcano
2019).
In the past, the island has experienced the creation of parasitic cones. These cones are formed when the central volcano erupts. The eruption of Stony Hill in the 18th century caused a lot of black lava to cover the southern part of the island. This shows that the island's land is still changing and moving. Newer volcanic events, like the eruption in 1961 that endangered the settlement on the northwestern plain and the 2004 underwater eruption that made pumice blocks,
have shown that the forces of nature on this remote and strong island are always there and can sometimes cause trouble (
The Tristan da Cunha Volcano
2019).
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GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
The Tristan da Cunha Island is situated in the South Atlantic Ocean, and tectonic activity in the area is caused by the contact of the African and South American plates, which divide by the Mid-Atlantic Ridge. As a result, the Tristan da Cunha region is on a tectonic plate boundary between the African and South American plates (Schlömer et al., 2017).
Tristan da Cunha is a group of islands that are about 18 million years old. Volcanoes made them along an extensive underwater mountain range called the Mid-Atlantic Ridge. The first eruption of Tristan da Cunha, the main island, happened around 3 million years ago. It came
up from the intense ocean floor, which was about 3,500 meters deep. This island with volcanoes is still active and shows that the Earth is still changing. In 2004, there was a big eruption under the sea about 24 kilometers away from Stony Beach. As a result, blocks of pumice were released.
These events show that the Earth's crust in this area is constantly changing, and it's really important to keep an eye on things to see if there's any danger from volcanoes that could affect the people and environment nearby. Tristan da Cunha is a group of islands in the South Atlantic Ocean that has a distinct and unique identity because of its geological past and ongoing volcanic eruptions (
The Tristan da Cunha Volcano
2019).
The October 1961 eruption of Tristan da Cunha had two effects. On the plus side, it resulted in the construction of a new volcanic cone, which revitalized the landscape and provided
opportunities for scientific inquiry. However, the eruption caused havoc, including destroying essential infrastructure such as the canning industry and landing beaches, and posed difficulties for both human and animal populations. Despite the hardships, the islanders' willingness to return to their homeland demonstrates their great devotion to their distinctive habitat and way of life (
Tristan da Cunha volcanic interlude 1961 – 1963,
2021).
GEOL 100 – Physical Geology - Week 2 – Authentic Project – Volcanoes (POINTS)
References
Global volcanism program: Tristan da Cunha
. Smithsonian Institution | Global Volcanism Program. (n.d.). https://volcano.si.edu/volcano.cfm?vn=386010
Schlömer, A., Geissler, W. H., Jokat, W., & Jegen, M. (2017). Seismicity in the vicinity of the Tristan da Cunha hot spot: Particular plate tectonics and mantle plume presence. Journal of
Geophysical Research: Solid Earth
, 122
(12). https://doi.org/10.1002/2017jb015017
The Tristan da Cunha Volcano. (2019, July 31). https://www.tristandc.com/earthvolcano.php
Tristan da Cunha volcanic interlude 1961 - 1963
. Tristan da Cunha Website. (2021, October 19).
https://tristandc.com/history1961-1963.php