Blog #4: Lava Tubes in the Galapagos

Traditional Caves in the Galapagos Islands are not as predominant as lava tubes. Lava tubes can be found on the town of Bellavista on the island of Santa Cruz. Santa Cruz is the most populated island of the Galapagos and where most tourists start their exploration. The Charles Darwin Research Station is located in Santa Cruz as well as, Galapagos National Park Headquarters and Giant Tortoise Preserves.

In Bellavista one can find lava tunnels.  Lava tunnels are formed when volcanic eruptions occur. Next the top of  the lava flow hardens, while the inside of the lava continues to maintain extreme temperature and creatives tubes.

Entrance to lava tube: Source:http://www.travelblog.org/Photos/3762135

Inside lava tube:   http://svsoggypaws.blogspot.com/2010_01_01_archive.html

Below is a diagram of how a lava tube is formed...

When a volcano erupts in the Galapagos, lava flow creates lava sculptures in these lava tubes, called Stalactites. In the lava tubes a verity of structures form when hot lava flows into the tubes causing lava to splashes onto ceilings, walls and ground. When lava hardens it creates speleothems an example is flowstone fielding and stalactites. Flowstone fielding occurs when lava begins to cool and slows down in speed than it clumps into all sorts of shapes. Both Shark tooth and Splash Stalactites are hanging Stalactites. They form when a rush of lava splashes and hits the ceiling of the tube. Temperature and humidity drop which then allows the lava time to harden until the next flow of lava adds to the formation (pictures 1&2 below).

Source:  http://fast.ucdenver.edu/case/1202/Landscapes/KarCoast/Karst/FlowstoneFielding.jpg

Source:  http://www.goodearthgraphics.com/virtual_tube/virtube.html

Lava flow makes rigid markings along the path it is navigating through. This type of  solid framework is typical of pahoehoe. Pahoehoe are made of basaltic rock meaning smooth, it's temperature reads between 1100 to 1200 degrees celsius. Although pahoehoe's can be seen in different shapes, one of the most predominant is ropy pahoehoe (Picture 3 on the right) and one of the lest seen is dentritic pahoehoe (Picture 3 on the left).

Blog 3: Weather

Weather patterns in any particular location result from a number of factors. In the Galapagos, the local climate is affected by elevation, latitude, wind direction, topography and ocean currents. Depending on the season, ocean currents bring warm or cold water to the region. These currents help cool or warm the air surrounding the islands. For example, cold currents have a rapid cooling effect on the air above them. On the contrary, warm currents quickly increase air temperature and humidity in the immediate area. These changing water temperatures create an ever-changing climate on the surrounding islands. This form of climate change creates a predominately warm and dry climate in the Galapagos.

Paths of Ocean Currents

Affects of climate change on the Galapagos Islands

The Galapagos land climate can range from dry to warm humid regions.

To determine climate in the Galapagos temperature and percipience are tow key factors.

1.Temperature:

 

 

 

 

 

 

 

 

2.Percipience:

 

 

 

 

 

 

 

  

 

 

 

 

 

source:  http://www.pmel.noaa.gov/tao/elnino/impacts.html

The Inter-Tropical Convergence Zone (ITCZ) helps guide the path of the oceans currents in the Galapagos region. The ITCZ results from convergence of the Humboldt and Panama Currents which flow through the Galapagos region.

Source:  http://www.srh.noaa.gov/jetstream//tropics/itcz.htm

• Humboldt Current-December through June the Humboldt Current slows down allowing the east trade winds to bring in the warmth. 
• Panama current- The Humboldt current also brings in poor nutrient water along with the Panama current.

El Nino is a wide ranging climate pattern, which results in altered ocean currents in the Galapagos region. During El Nino, the Galapagos experience increased sea surface temperatures and a decrease in nutrients.

The diagram is an example of changes that are common patterns in the Galapagos. The first diagram is a picture of the ocean during normal conditions, as well as in abnormal conditions such as in El Nino.

Note: the white arrows indicating the direction of the Trade Winds (from east to west in normal conditions and reversing from west to east in El Nino conditions). In many El Ninos the Trade Winds may not actually reverse, they just slow down or stop. Also notice the depth of the thermocline (shallow area near the Galapagos in normal conditions) it has been leveled, creating the oceans water bed to rise.

Source: http://www.marinebio.net/marinescience/02/englobe.htm

Source: http://www.marinebio.net/marinescience/02ocean/englobe.htm

Preview

Mass Wasting and Erosion in the Galapagos

Much of the Galapagos is composed of volcanic rock.  Since the Galapagos has frequent volcanic eruptions, we must consider the effect of these eruptions on the land.

The Galapagos Islands are made up of a specific chemical composition that makes up its rock formations. The composition of these rocks is an important factor that determines the types of erosion that occur. 

The typical rock composition found in the Galapagos is basalt rock. Basalt rock, also called mafic rock, is found on the majority of the islands. These rocks are created by lava as it hardens.
                                                         
                                                           Photo: Basalt Rock

http://www.geol.umd.edu/~jmerck/GEOL388/images/03/basalt.jpg

Rock Formations:
Pinnacle Rock was formed when lava reached the sea which then created a phreatic explosion. The two extremes in temperatures (hot lava and cool ocean water) created an explosion and formed Pinnacle Rock. This type of land formation contributes to frequent additions to the islands.


                                                Photo: Pinnacle Rock

http://www.google.com/imgres?imgurl=http://www.photoseek.com/86GAL-10-16_Pinnacle-Rock-beach-Bartolome-Island.jpg&imgrefurl=http:

Additional factors are involved in shaping the rock formations that we see today in the Galapagos including erosion and mass wasting.

Factors that cause erosion:
1Wind
2Water
3 Ice
4 Gravity

                                       Wind can give new shape to existing rocks.  

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjNsDvo_Yu55kuVDtxZRggZLOcvdgDvLVdOgFIzgzrkQwnr5tEDjWTZoTXCTzQJsEIwid4OFRUJH9YvK4RzDp21JL37fM02WqVxIjf0m2aqWCFkyB2ktRNDJ4yJx2BFK7gg0ypOzqtPW6M/?imgmax=800

Phenomenons like Pinnacle Rock and wind erosion (seen above) highlight how the islands are in constant change.

Mass Wasting is the rapid downslope movement of angular slope material. (source, Mass Wasting of Slopes class notes). One example of mass wasting is slope failure which typically occurs in the Galapagos. The type of slope failure that most often takes place in basalt rock is a slump (also called a rotational slide). Slumps are common along river banks and sea coasts, where erosion has under-cut the slopes.  Heavy rains and earthquakes can also trigger slumps. All of these factors are present in the Galapagos leading to slumps that we see in the rock formations of these islands.

http://www.tulane.edu/~sanelson/geol204/masswastproc.htm

Volcanoes

Volcanoes in the Galapagos:

Volcanoes have played a huge role in the physical formation of the Galapagos. Consistent volcanic eruptions lead to island formation over time.

There are many factors that make the Galapagos unique. Below are some of the worlds volcanic hot-spots Hot-spots are located in the earth's mantle where magma is formed from volcanic activity.

                                         http://pubs.usgs.gov/gip/dynamic/world_map.html

Fernandina Island is the largest island of the Galapagos, which is home to La Cumbre Volcano. This volcano is still active and last erupted in 2009.

                                          Photo: La Cumbre Volcano

NASA images of the Fernandina Plume (NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

The Cumbre Volcano is considered a Basalt Shield volcano. Basalt Shield volcanoes can be identified by their oblique shape. Other characteristics of shield volcanoes are their low gently sloping side. They are usually found at constructive or tensional boundaries.

Add chttp://www.bbc.co.uk/schools/gcsebitesize/geography/images/tec_015.gifaption

They are formed by eruptions of thin, runny lava. Eruptions tend to be frequent but relatively gentle.

Add http://trendsupdates.com/la-cumbre-volcano-erupts-after-four-years-of-calm-lava-feared-to-affect-galapagos-wildlife/caption

Frequent Volcanic Eruption Dangers:

The unique species of wild life and plant life that live on the Galapagos are one of a kind.  Volcanic eruptions often kill many plants and animals that only exist in the Galapagos. It's rare forms of species would be difficult to replace. Another long term impact of frequent volcanic eruptions is that it may affect tourism. The volcanoes of the Galapagos including La Cumbre are major attractions for tourism, which is a major source of revenue for these islands.

Introduction

Source: U.S. Central Intelligence Agency.

Hello! My name is Roxana Gonzalez. I am originally from California but have fallen in love with Colorado. I’m excited to learn about physical geography since I love the outdoors and nature.

I have chosen the Galapagos Islands as my blog topic. I became interested in theses islands ever since my first biology class. As I learned about Darwin and the Theory of Natural Selection I grew even more intrigued. The Galapagos Islands are fascinating place for me.  The wild life on the island is extremely unique. There is a handful of very rare wild life on the island. I would love to learn why theses animals gravitate to this location and how the island originated. Lastly, I chose this location because it has always been on my bucket list of locations I would love to visit.