Types of rocks

What are the 3 basic types of rocks?

Just as any person can be put into one of two main categories of human being, all rocks can be put into one of three fundamentally different types of rocks. They are as follows:

Igneous Rocks

Igneous rocks are crystalline solids which form directly from the cooling of magma. This is an exothermic process (it loses heat) and involves a phase change from the liquid to the solid state. The earth is made of igneous rock – at least at the surface where our planet is exposed to the coldness of space. Igneous rocks are given names based upon two things: composition (what they are made of) and texture (how big the crystals are)

Sedimentary Rocks

In most places on the surface, the igneous rocks which make up the majority of the crust are covered by a thin veneer of loose sediment, and the rock which is made as layers of this debris get compacted and cemented together. Sedimentary rocks are called secondary, because they are often the result of the accumulation of small pieces broken off of pre-existing rocks. There are three main types of sedimentary rocks:

Clastic: your basic sedimentary rock. Clastic sedimentary rocks are accumulations of clasts: little pieces of broken up rock which have piled up and been “lithified” by compaction and cementation.

Chemical: many of these form when standing water evaporates, leaving dissolved minerals behind. These are very common in arid lands, where seasonal “playa lakes” occur in closed depressions. Thick deposits of salt and gypsum can form due to repeated flooding and evaporation over long periods of time.

Organic: any accumulation of sedimentary debris caused by organic processes. Many animals use calcium for shells, bones, and teeth. These bits of calcium can pile up on the seafloor and accumulate into a thick enough layer to form an “organic” sedimentary rock.

Metamorphic Rocks

The metamorphics get their name from “meta” (change) and “morph” (form). Any rock can become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals which make up the rock become unstable and out of equilibrium with the new environmental conditions. In most cases, this involves burial which leads to a rise in temperature and pressure. The metamorphic changes in the minerals always move in a direction designed to restore equilibrium. Common metamorphic rocks include slate, schist, gneiss, and marble.

Inactive Volcanoes of Honduras

Dormant Volcanoes in Honduras

Four Classic Volcanoes in Honduras

            One of the most exotic countries in Central America is Honduras.  It consists of very high elevations and low valleys and green luscious tropical rainforest. Another one of its interest attractions is the dormant volcanoes that can be found there.

            It’s estimated that Honduras is covered with 40,000 square kilometers of trails, about 100 necks have been identified, 32 of these are located around Tegucigalpa the capital, and most of them are unnamed. Most volcanic cones are located in the central, southern, and eastern parts of Honduras. This area include the “classic” volcanoes in Honduras and the most well-known.

            Some volcanoes in Honduras are known as the classics such as Volcan el Tigre which is a strato volcano, Isla Zacate Grande which is also a strato volcano, Lake Yojoa which is a volcanic field, and Utila Island which is covered with pyroclastic cones. These volcanic mountains have an altitude less than 1,400 meters, but they are extremely steep and have numerous isolated narrow valleys. They have erupted in the last 10,000 years, but not in historical time.

            Volcan El Tigre is considered one of the most impressive in Honduras. It is located in the Southern Coast of Honduras in an Island called Isla del Tigre, in the Gulf of Fonseca. It has an elevation of 783 meters. It has beautiful scenery. It is near the equator and coast, thus the climate is extremely hot and humid. You can reach the Island from Tegucigalpa. The land you cross to reach the island is full of rainforest and the elevation increases as you get nearer the Island.

           

 

            Zacate Grande Volcano is located in Isla Zacate Grande. It’s a Holocene Strato volcano. It’s an Island 7X10 km wide across a narrow strait from the end of a peninsula surrounded on three sides by the Gulf of Fonseca and Chismuyo Bay. It’s located North of Isla El Tigre, however Zacate Grande is extremely eroded. It is covered with deep valleys from the top of the volcano to the base of the volcano.

 

 

 

            The Lake Yojoa volcanic field is located in northern end of north-central Honduras, which also contains magnificent scenes. It’s made up of a group of Pleistocene-to-Holocene scoria cones and collapse pits. A variety of rocks from tholeiitic basalts to trachybasalts, trachyandesites, and trachytes, can be found there. Several of the pyroclastic cones contain well-preserved craters. Most of the pyroclastic cones consisting of basaltic scoria and agglutinate, are 100-200 M in height. There are indications of lava flows from in all directions from the cone. A few Quaternary lava flows occure in the Sulu graben along the Carretara del Norte north of Lake Yojoa.

           

 

            Utila Island is the smallest of the Caribbean Bay Islands in Honduras. It is covered with pyroclastic cones, and it’s a Holocene volcano Island. Basaltic lavas and tuffs were erupted onto a coral-capped erosional surface.  Stuert Hill, which is also pronounces as Stuart Hill, is a pyroclastic cone that was constructed at the center of the volcanic terrain, and Pumpkin Hill is a small littoral cone located along the NE coast of the island. This is also the highest point of the island, which rises 74 M above sea level.

 

Why Central America, Mexico, and the Caribbean is vulnerable to earthquakes?

I’ll talk about why these continents and countries are vulnerable to seismic activity, the mayor reason this happen is because  it lies on the edge of the gigantic pacific plate, on the infamous ‘ring of fire’ , an arc of plate boundaries encircling the Pacific Ocean.

The boundaries of the Pacific plate are very unstable, causing earthquakes and volcanic activity along the west coast of the Americas as well as east Asia.

At their boundaries, the plates move against each other, creating massive pressures. These pressure gradually build up until finally there is a sudden movement.

Central America is also home to a chain of active volcano that stretch from Mexico City all the way down the Panama. According to seismologists, the volcanic geological patterns mean the effect of earthquakes is more destructive than might otherwise be the case.

The color dots are recent earthquakes that happened.                          Yellow = less than 5,0 ritcher scale                           Orange = more than 5.0 ritcher scale  

These countries are so vulnerable that they share a place of the top 10 countries with most earthquakes.

One of the countries with greatest earthquake is undoubtedly  Haiti in January 2010. The quake killed between 100,000 and 300,000 people (various estimates have been put forward and countered by others), and caused untold damage to the Western Hemisphere’s poorest country, particularly in and around the capital, Port-au-Prince.

Los Recursos Minerales de Honduras

De C. Colón, se dice, que observó que los pescadores en la costa de lo que es hoy Honduras, los cuales usaban en sus redes contrapesos de oro, y es quizás así como nació la fascinación por riqueza minera en Honduras, especialmente el oro.

La minería en Honduras como en otros países en que se llevó a cabo la llamada Conquista, se inició antes que la agricultura. La fundación de pueblos españoles se debió principalmente al deseo de los conquistadores de controlar los grupos indígenas ya establecidos y la incipiente agricultura a la necesidad de alimento para mantener la fuerza laboral minera existentes.

La gran riqueza de Honduras ha sido descrita tanto por los mismos conquistadores como Por innumerables viajeros visitantes, especialistas en geología, científicos diplomático al Informar sobre el país, etc. como un potencial de posibilidades ilimitadas.

En 1870 un mineralogista, un tal Mr. Gourmes quien visitó Honduras, expresó que era más fácil encontrar minas que hombres para trabajarlas, la descripción que él hace de la riqueza Minera hondureña prevalece en nuestros días ya que el oro, la plata, el plomo, zinc, antimonio, carbón, mármol, piedras preciosas, manganeso, asbestos, así como otros de reciente importancia tales como el platino y sus derivados, iridio, rodio y rutenio que valen mucho más que el oro han sido muy poco explotados o no han sido explotados del todo.

Respecto al oro, se ha determinado que el 60 por ciento de los ríos hondureños arrastran oro. El famoso río Guayape, su afluente el Jalán, el río Guayambre que se une al Guayape para formar el río Patuca que desemboca en el Atlántico arrastran oro en toda la extensión del cauce de más de 300 km. A pesar que desde los tiempos coloniales se ha explotado el oro en los ríos antes mencionados, la fuente aurífera, la madre de donde procede el metal nunca se ha investigado a fondo, permaneciendo así en espera de su descubrimiento.

Actualmente Honduras aun no cuenta con una producción minera de significación, pero que continuan dañando el ambiente, sólo unas cuantas minas se han explotado esporádicamente y sólo dos actualmente trabajan en forma permanente, la AMPAC en el departamento de Santa Bárbara y los Minerales de Copán en el Departamento del mismo nombre, se encuentran en el país algunas compañías desarrollando trabajos de prospección, exploración y promoción en varias zonas mineras del país, el solo llevar a cabo las actividades mencionadas ya es un buen negocio tanto para las compañías como porque aun en pequeña escala generan empleos, y dejan divisas.

Los recursos minerales de Honduras consistió en el cadmio, el cemento, carbón, cobre, oro, yeso, plomo, piedra caliza, mármol, puzolana, riolita, sal, plata y zinc, un producto de exportación. Transporte inadecuado siguen dificultando el pleno desarrollo de los recursos minerales.

Att: Delmer Isaac Pineda

 

 

Orogeny or orogenesis

Orogeny is the mountain-building event. This is caused by plate tectonic processes that squeeze the litosphere together.It may also refer to a specific episode of orogeny during the geologic past. Even though tall mountain peaks from ancient orogenies may erode away, the exposed roots of those ancient mountains show the same orogenic structures that are detected beneath modern mountain ranges.

In classical plate tectonics, plates interact in exactly three different ways: they push together, pull apart or slide past each other in, respectively, convergent, divergent or transform or lateral motion. Orogeny is limited to convergent plate interactions; the counterpart of orogeny for divergent settings is called taphrogeny. The long regions of deformed rocks created by orogenies are called orogenic belts, or orogens.

Orogens can be bent and altered by later events, or severed by plate breakups

Orogenic belts can form from the collision of an oceanic and continental plate or from  two continental plates.

 

Tectonic Plates

From the deepest ocean trench to the tallest mountain, plate tectonics explains the features and movement of Earth’s surface in the present and the past.

Plate tectonics is the theory that Earth’s outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earths mantle. This strong outer layer is called the lithosphere.

The concept of plate tectonics was formulated in the 1960s. According to the theory, earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km (60 miles) thick and overlies a plastic layer called theasthenosphere. The lithosphere is broken up into about a dozen large plates and several small ones. These plates move relative to each other, typically at rates of 5 to 10 cm (2 to 4 inches) per year, and interact along their boundaries. Such interactions are thought to be responsible for most of Earth’s seismic and volcanic activity, although earthquakes and volcanoes are not wholly absent in plate interiors. Plate motions cause mountains to rise where plates push together, or converge, and continents to fracture and oceans to form where plates pull apart, or diverge. The continents are embedded in the plates and drift passively with them, which over millions of years results in significant changes in Earth’s geography.

 

How are mountain ranges formed?

Mountain ranges are a series or a chain of mountains that are close to each other. Mountain ranges form when pieces of the Earth’s crust that are called plates smash against each other this process is called plate tectonics.