Geology of Puerto Rico

Geology of Puerto Rico

Each of Earth’s regions has a unique geological origin that shows how it formed and the processes which determines its composition. The rocks are the way whereby scientifics study the geology of a region or country. In this case, it will be taken as an example the geology of Puerto Rico to demonstrate how this discipline is important to know the geological history of a region of Earth. This would be a general review of the most important aspects that govern the geology of this archipelago. The geological history of Puerto Rico and its geological province will also be discussed in a general way.

Puerto Rico and the Virgin Islands are located in the eastern part of the Greater Antilles between the Atlantic Ocean and the Caribbean Sea. The oldest rocks of Puerto Rico date from the Jurassic period (195,000,000 years ago) and are located in the southwest part of the island. This island is formed mostly by volcanic rocks, deposited during the Cretaceous period (135,000,000 years ago). The Cordillera Central of Puerto Rico its a topographical feature and it is composed of primitive volcanic rocks. Puerto Rico experienced certain geological processes that shaped its current formation. The volcanic activity of the Cretaceous period formed scattered islands in the region, recognized as active centers. In the shallow waters around these islands grew corals and calcareous skeletons organisms, these accumulated forming reefs and their skeletal remains became in limestone, these were covered with lava from new volcanic eruptions. The erosive forces of rivers wore and molded the mountains allowing the island to continue emerging, the reefs in the north and south of the island were exposed to surface during the Tertiary period (65,000,000 years ago). The weathering and erosion of the rocks allowed the formation of superficial deposits in the Quaternary period (10,000 years ago).

Geological provinces are characterized by relief and the landform, it constitutes the natural expression of rocks and geological process that have occurred. Puerto Rico is divided into three main geological provinces: igneous province of the central mountainous interior, limestones province and province of surface deposits of the coastal plains. The igneous province of the central mountainous interior is composed of volcanic, plutonic, sedimentary clastic and nonclastic rocks and some metamorphic rocks, is the biggest province and is subdivided into three regions: igneous southwestern province, igneous central province and igneous northeastern province; it covers the Cordillera Central, Sierra de Cayey, Sierra de Luquillo, Sierra Bermeja (with the oldest rocks), some hills, interior valleys and the erosion surface of Barranquitas. Limestone province is subdivided into two regions: limestone northern province and limestone southern province. The limestone northern province goes from Aguada town to Loiza town covering 135 km² and it is where the dissolution of limestone forming sinkhole, caves, caverns, mogotes and karst topography occur, this is produced by its rainy and wet climate; the limestone southern province goes from the coastal area of Cabo Rojo town to the hills of Juana Díaz town and it is composed of limestone much older than the north limestone and not abound sinkholes, caverns, mogotes and karst, this is due to its dry and arid climate which does not allow the limestone to dissolve quickly. The province of surface deposits of the coastal plains is the smallest geological province of Puerto Rico, it includes flat areas near the sea were there are deposited crustal materials from rivers, runoffs and wind. The adjacent islands of Puerto Rico belong to the geological framework of the big island, separated by tectonic events or changes in sea level.

Although Puerto Rico is a small archipelago, its geology is diverse, this is important for human settlements. Constructions created by man are located over terrains with particular geological features. This means that each road, house, building, monument and any infrastructure must be built respecting the geological conditions. Puerto Rico should not be the exception, it is important to study and understand the territory and relief to create safe constructions, avoiding altering the natural and geological processes of these islands. This can reduce devastation from natural disasters and therefore the human losses.  

References:

Information:

Alonso J., Serie Naturales. (1998). Descubrimiento 9 Ciencia Integrada.         

            Puerto Rico: Ediciones Santillana, Inc.

Map:

http://geolboriquen.blogspot.com/2012/02/mapa-geologico-general-de-puerto-rico.html

Pictures:

Luis Espada

The Rocks: Formation and Types

The Rocks: Formation and Types

An essential and important part of Earth Science is geology. Geology is the science that studies the dynamics and physical history of Earth, the rocks of which is it composed and chemical, biological and physical changes that occur on Earth. As is established in the definition, geology studies the composition of Earth, mainly, the rocks. The rocks are aggregates of solid minerals of natural origin, whose components are defined and are arranged inside forming crystals. The Earth is a rocky planet, this mean that most of its mass is in the form of rocks. Therefore, we can study the types, formation and changes of the rocks in a general form. 

First, we need to know the types and formation of the rocks that exist over the Earth’s surface. In Earth there are three kinds or rocks: Igneous, Sedimentary and Metamorphic. The same can be classified by their origin, formation, composition and their changes.

Igneous rocks are formed by the cooling the molten rock product of volcanic activity. These rocks are classified into two main subgroups: extrusive igneous or volcanic and intrusive igneous or plutonic. Volcanic rocks consists of fine crystals formed by rapid cooling of lava near the Earth’s surface; some of these rocks are rhyolite, andesite, basalt, scoria, pumice and some pyroclastic rocks (formed by pieces of rocks that have been thrown into the air by volcanic explosion)  like gaps, tuffs, volcanic conglomerates and basaltic flows. On the other hand, the plutonic rocks are composed of thick crystals formed by the slow cooling of the magma inside the Earth’s surface; some of these rocks are granite, granodiorite, diorite, gabbro and periodite. These rocks are exposed to Earth’s surface by erosion and weathering processes.

Sedimentary rocks are formed when sediments or fragments are compacted and cemented, also it accumulates layers upon layers through the years. These rocks are classified onto three main subgroups: clastic, non-clastic and bioclastic. Clastic sedimentary rocks are formed by pieces of other rocks. Example of this are conglomerates, gaps, sandstone, limonite, argillaceous slate. Non-clastic sedimentary rocks are these formed by materials that have precipitated directly from water, rocks like dolomite, flint, halite (salt rock) and gypsum rock are samples of these types of rocks. Bioclastic sedimentary rocks are originated by the accumulation of skeletons of sea plants, animals and coral reef that have died. Limestone is a bioclastic sedimentary rock formed by calcium carbonated and calcite; hard coal, composed by vegetal materials is also a type of these rocks.

Finally, we have the metamorphic rocks that are formed by changes in temperature and pressure of the rock and other chemical processes. These rocks can be formed from other metamorphic rocks, sedimentary or igneous. There exist two types of metamorphism: contact metamorphism and regional metamorphism. Contact metamorphism is produced when igneous rocks and lava flows remains trapped between the layers of other rocks, these are classified as not foliated rocks (rocks without sheets), are formed by chemical reactions, high pressure and temperatures, are subdivided by grain size; marble (originated from limestone and calcite compound) and quartzite (originated from quartzarenite and quartz compound) are not foliated rocks of thick grains; serpentine (a slippery blue-green rock originated from olivine and basalt rocks and quartz and amphibole composed) is a not foliated rock of fine grains. Regional metamorphism is formed more slowly that the contact metamorphism and it includes large regions and it has a deeper metamorphic rock zone, are formed by big pressure and high temperatures, these are classified as foliated rocks (rocks with sheets); schist (originated from phyllite and mica composed) and gneiss (originated from granite or volcanic rocks and composed of different minerals) are foliated rocks of thick grains; phyllite (originated from argillaceous slate and mica, quartz and chlorite composed) and slate (originated from argillaceous slate and mica, quartz, clay and chlorite composed) are foliated rocks of fine grains.

For humans beings the study of rocks is very important. Many monuments, sculptures and buildings are made from different types of rocks. They are also used by sculptors to make buildings and artistic works such as marble. For example cemetery tombstones are made from granite and basalt rocks. The statues are made from sedimentary rocks, specifically limestone rocks. These and other economic uses are indispensable for constructions made by humans over time. 

References:

Information:

Serie Naturales. (1998). Descubrimiento 9 Ciencia Integrada.  Puerto Rico:

Ediciones Santillana, Inc.

    

Curso General de Suelos (AGRO 3005). Laboratorio #3: Rocas y minerales

http://www.geologia.uchile.cl/las-rocas-y-sus-procesos-de-formacion

http://cienciaybiologia.com/rocas-sedimentarias-igneas-metamorficas/

http://www.dictionary.com/browse/geology

Picture:

https://www.pinterest.com/pin/429038301973237753/

Earth Science and it Applications

Earth Science and it Applications

As we know, science is a discipline that consists of many specialties. One of these specialties is Earth science, the science that studies Earth. Although this branch is associated with geology, Earth science is a broader and more comprehensive study of all the Earth. This means, that geology is more specific in the study of the composition and formation of Earth. It is for this reason that Earth science has different applications.

The applications of Earth science are varied. We can identify many sub-branches into this general branch. For example, geology is the study of Earth from a more specific study, this is a related application. Meteorology and climatology are disciplines specialized in the weather and climate patterns, respectively. Earth science also studies water in the planet. Oceanography has the objective to study everything related with the oceans and seas and it interrelates with biology, geology, chemistry and physics; hydrology also studies the water, but only the one present on the Earth’s surface. The natural resources are also an important part of this science, these determinate the energy sources available for human use. Astronomy also has interrelationship with terrestrial studies. Another important application is geography that studies the human interaction with the nature environment.

Like any natural science, Earth science is based on the use of the scientific method. This method consists on a series of steps to resolve a hypothesis with an experiment, with the aim of analyzing the data to support or rule out this hypothesis. With the use of this process we can answer questions like: What is it?, When?, Where?, How? and Why?. Questions as: How sedimentary rocks are formed?, Why the waves are generated?, or Where is it the highest frequency of hurricanes in the Atlantic Ocean? are some of many questions that scientists have grappled. This and other questions are answered mostly with the aid of the scientific method.

Earth science is an essential discipline to the other sciences and therefore for humanity. It is responsible for studying the nature and how the humans interact with environment. Also natural phenomena and disasters that affect us directly or indirectly are studied by this science branch. Throughout history human beings have tried to understand nature. For this reason, knowing and understanding our natural environment is very important to us, this is the main role of Earth sciences and their interactions.

References:

Information:

Serie Naturales. (1998). Descubrimiento 9 Ciencia Integrada.  Puerto Rico:

          Ediciones Santillana, Inc.     

Picture:

http://blocs.xtec.cat/blogmedi/files/2014/12/1207791189_f.jpg

Branches of the natural sciences and their interrelationships

Branches of the natural sciences and their interrelationships

Everything around us is studied by science itself. Science is a discipline that includes many others branches. Each branch of science is specialized in different fields. When the principal branches share concepts with each other, we have other disciplines and therefore, their interrelationships. This forms the macroscopic world of science.

Natural Sciences are defined as the study of nature in order to decipher the theories and laws by which the natural word works. Ii is divided into five principal branches: Chemistry, Physics, Biology, Geology, and Astronomy.  Each one has a unique specialty that distinguishes it from the others. Chemistry is the science that studies matter and the changes it undergoes. Physics involves the study of matter from the perspective of its motion through space and time, along with related concepts such as energy and force. Biology is the study of living organisms and their interrelationship with their environment. Geology investigates and studies the Earth, the rocks from which it is composed, and patterns and processes by which they change; it is associated with the discipline of Earth Science. Astronomy involves everything related with celestial space, all that is beyond Earth.

The interrelationship of natural sciences branches generate others sub disciplines. For example, when we combine chemistry and physics, we have physical chemistry, that studies matter with concepts of chemistry and physics combined. Biology and chemistry intertwine to form biochemistry, the chemistry of life. Physics and geology form geophysics and study the forces and motions of the Earth, like the earthquakes. In the same way, astronomy and biology combines to form astrobiology, the science that studies the life beyond Earth. These and others interrelationships are summarized in the science branches pentagon of the main branches of science (in the image), that involve two geometrical figures: a pentagon and a star. Other branches are inside there like ecology, meteorology, kinetic, organic chemistry among others.

           This blog will focus on earth science and geology, but also will have the influence of the other sciences. Therefore this blog will be interdisciplinary and multidisciplinary; this means that integration and knowledge of other disciplines are required. The main objective of science is to build and organize knowledge to understand the nature and the universe with the use of testable explanations and predictions. This is the key to understand every phenomenon that happens in the Earth and beyond.

References:

Academia. Definition of Science The Branches of Science and their Meaning,

            http://www.academia.edu/10792252/Definition_of_Science_The_Branches_of_Science_and_their_Meaning

Serie Naturales. (1998). Descubrimiento 9 Ciencia Integrada.  Puerto Rico:

          Ediciones Santillana, Inc.