A geologist in distress by Nahúm Méndez

A geologist in distress by Nahúm Méndez

Small popularization test to introduce us to the wonderful world of geology Ideal for all those who want to start and discover what this science does.

A geologist in distress. A journey through time and into the deepest part of the Earth

The author is Nahúm Méndez, geologist and author of the blog of A geologist in distress. I have been following him for a long time on his twitter @geologoinapuros

I really liked it, but I would have liked him to get into field geology more. I hope that there will be a second volume already entering into the subject of types of formations, rocks, minerals, etc. A document that helps a naturalist to go out into the field and understand what types of formations he is seeing and why they have formed.

I want to highlight 2 things.

  1. Throughout the book we are emphasized and shown how unique geology, astronomy, and climate are. Geology and Climate The effects of geological events vary the climate, but variations in climate also cause geological disasters
  2. The description of how the extinction of the dinosaurs could be. It seems to me a very very interesting passage and reconstruction.

I miss

A brief explanation of geological timescales, at least of the ones used in the book. Sometimes he talks about eons and other times about ages, times, and he has gotten me off track. Perhaps an annex at the end with this information would have been a good idea.

It is a point that I want to review well with external information. I now leave some notes on the different chapters, things to remember and other topics to expand in the future.

If you want to know more about the importance of the oceans, see the review of A blue world by Sylvia A. Earle


The formation of the solar system

All part of the formation of the solar system and our planet is also very well explained and with the advantage of having impressive images in the special issue of Nationa Geographic

From the Big Bang to the formation of the solar system based on the grouping of elements by the gravitational attraction that causes that in the densest areas of material they clump together, forming small meteors that continue to collide with each other until they acquire so much mass that in the nucleus begins to fuse, to recombine and to form more elements.

Explain the different types of planets in the system, rocky and gaseous, and why they form

The Kuiper Belt and the Oort Cloud. Oort, between Mars and Jupiter. most bodies are rocky and metallic

The largest asteroid is Ceres with a diameter of almost a thousand kilometers

Kuiper beyond Neptune's orbit are made of ice.

The formation of the earth and the moon

Formation of the earth similar to the other planets of the solar system. Explain that the earth had rings and the three most accepted theories of the formation of the moon, fission, enunciated by George Darwin, son of Charles Darwin at the end of the XNUMXth century. The one of the capture and the one of the great impact that is the most accepted

The iron catastrophe that occurred when the Earth exceeded 1538ºC, the temperature at which iron melts. The planet was in a viscous state and the heavy elements sank into the core.

The Precambrian

Lasts 4.000 billion years, 90% of Earth's history

James hutton, realizes that geological time scales were broader and that the earth age calculated with biblical texts did not work

From the radiometric radiation that take advantage of the disintegration and isotopso, values ​​close to the current ones begin to be calculated.

Arthur Holmes in 1940 with these techniques dates the Earth in 4500 million years.

From here we go on to an explanation of the different layers of the Earth, of its internal structure

From Wegener's continental drift to plate tectonics, which is the accepted theory today

And the chapter ends with the great glaciations of this period when for a hundred thousand years it was cooling until it was completely filled with ice for 50 million years. It could be due to different factors. Continental masses in another location that reflected heat more rather than absorbing it. It rained much more and water and co2 reacted with the rock and as there was little co2 there was less heat in the atmosphere and a possible eruption of a volcano whose ashes would reflect the sun's rays and would not allow the heat to enter

The Paleozoic

It is centered in Cambrian with the formation of Pangea, one of the different supercontinents that has existed with its emerged surface (Gondwana9 and then in the Carboniferous

Of the five great extinctions that have occurred on our planet, 3 occurred in the Paleozoic

Of extinctions, fçosible and of the era of coal, the carboniferous, of the appearance of plants on earth and of how the Ordovician-Silurian ice age possibly caused a glaciation

How it fossilizes and how supercontinents are formed

And the fearsome extinction of Permothries between the Permian and Triassic, the but extinction of history and that was the one that paved the way for the dinosaurs

The Mesozoic

From 250 million years ago to 66 million years ago. It is known for being the era in which the dinosaurs ruled the Earth.

It includes, Triassic, Jurassic, Cretaceous which is what sounds the most to all of us. In Jurassic and Cretaceous there are significant sea level rises.

The first flowering plants also appear. And in the Cretaceous, bees appear.

In the Triassic the first mammals are seen, which were small in size and the first birds that come from the evolution of dinosaurs are also seen

Extinction of the Triassic-Jurassic, it is not the best known despite having killed 1/3 of the species on Earth. After this extinction, the dinosaurs began their reign.

In the Paleozoic most of the Carbon reserves were formed and in the Mesozoic most of hydrocarbons such as oil.

Cretaceous-Paleogene extinction. The best known, that of the meteorite that extinguished the dinosaurs. 75% of the earth's species disappeared

Chicxulub crater between the Yucatan peninsula and the Gulf of Mexico

A 2 thousand km around the impact would knock down the forests, an earthquake of magnitude 01 or 11 was generated.

The Cenozoic (era of mammals)

It means new life. The continents move toward their current positions as Pangea breaks. It's a time of global cooling

The Messinian Salinity Crisis

At the bottom of the Mediterranean there are large salt deposits, in some areas 3km thick. It is assumed to have been dry or practically eo for 300.000 years. It is assumed that the area of ​​the Strait of Gibralatar was raised by the collision of two plates and no water entered. At the time that the Mediterranean reentered and filled, talking about rises of 10 m per day and water entering at 300km / h with waterfalls of more than 1000 meters.


New Zealand would be part of Zealand, the part that remains emerged. Zeeland was part of Gondwana, after Pangea broke 200 million years ago.

The Quaternary and other ice ages

Astronomy and theories that relate the movement of the earth to a quaternary ice age. Milankovitch cycles that regulate the Earth's climate

Recent dryas

He ends up talking about volcanoes and climate and the global warming that is coming.

The future of the Earth

Mention to the Anthropocene

The search for space resources, metals, minerals, water in space asteroids,

And possible causes of the end of the earth, geological risks that threaten us.

Photo Gallery

Some of the photos that I have taken to accompany the review, with calcite, with a geode and with several fossils


Specific topics to find information about

  • Kepler 444
  • Chondrules
  • The iron catastrophe
  • The magnetic field as a protector
  • Basic principles of geology by Nicolás Steno
  • Valdivia earthquake

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