Time is a flowing illusion. There are as many types of time as there are frames of reference we define. At the very least, we can start with a cosmological time scale that spans from the origin of the universe—beginning with the Big Bang—to the present day. And that amounts to 13.7 billion calendar years. Or we can start with the birth of our planet 4.566 billion years ago and speak of geological time. But there is also prehistoric time and historical time; a human time for each of us and an inner time. Geology is a historical science, and time is a constant source of contemplation. Hence, the guiding motto that defines the geological sciences is: Mente et Malleo—with mind and hammer. One of the missions of geologists is to unravel the history of our planet and its neighbors in the solar system. Conceptions of the planet’s age range from those seven biblical days and later Bishop Usher’s genealogy of the patriarch Abraham, to more than 8 billion years according to the chronology of the ancient Hindu sages in their Vedas. The great Greek philosophers of antiquity also expressed their vision of time, and after a period of obscurantism that lasted 1,500 years, seminal ideas resurfaced during the Renaissance. The following centuries would be marked by a back-and-forth analysis of the greater or lesser duration of so-called creation.Leonardo, Steno, Hutton, the Count of Buffon, Humboldt, Werner, Lyell, Darwin, Lord Kelvin, and many others outlined their points of agreement and disagreement regarding the depth of geological time. Today, everyone agrees that this—the concept of deep time—was geology’s greatest contribution to universal science. The discovery of radioactivity, in which Rutherford, Becquerel, and the Curies played leading roles, revealed that certain chemical elements had unstable isotopes and that these transformed over time at a fixed rate independent of physical or environmental conditions. A simple example is uranium transforming into lead (or potassium into argon, or rubidium into strontium), and that transformation time is measurable and convertible into calendar years. The baton was then taken up by the English geologist Arthur Holmes. This gentleman set out to search for rocks of different types and relative ages based on their spatial distribution in order to date them, as is generally the case from the heart of the mountains toward the periphery. Thanks to this, he began to develop a geological time scale by identifying rocks from the Proterozoic, Paleozoic, Mesozoic, and Cenozoic periods to assign them radiometric dates.
Based on this important work, it became possible to assign absolute ages to fossil-bearing rocks for which only relative ages had previously been available. The evolution of life, from the Precambrian to the present day, left behind records that were preserved as spatiotemporal singularities and constitute true milestones in geological time. From those primitive stromatolites, through the Ediacaran plasmodial globes, trilobites, and dinosaurs, to mammals and finally humans.
Nature has bequeathed to us some treasures and useful guides preserved as “frozen time capsules,” such as zircons, a common and abundant mineral composed of a zirconium and hafnium silicate; some of these, found in Australia, have been dated to between 4.2 and 4.4 billion years old. Or the meteorites from the original solar nebula that established the age of the Earth’s formation at 4.566 billion years. Just as when we observe a simple piece of amber, 20 or 30 million years old, that perfectly preserves a mosquito, a fly, a spider, or some other small organism inside it, as if it were encased in a piece of ice; although in this case it is a transparent, citrine-yellow fossil resin derived from ancient trees. Thanks to isotopics, revolutionary advances are being made in understanding the origin and evolution of planet Earth. Ancient climates are being reconstructed, as are the times when deeply buried rocks were exposed, and the way in which the crust and mantle liquefied and fused through plate tectonics or plume tectonics, among countless other scientific advances.In this regard, it is worth noting that a state-of-the-art laboratory equipped with cutting-edge technology was established in Vaqueros (Salta) as a joint venture between a private firm (Geomap) and CONICET. The company in question is Late Andes S.A., which specializes in the study of zircon and apatite crystals, which are irradiated in Ezeiza and used to obtain data on the heating and cooling of crustal rocks, particularly regarding the formation of orogenic structures, among which the Andean system is a world-class example. The techniques applied are important in the oil industry for determining the age of hydrocarbon-bearing source rocks, as well as in geothermal energy, mining, and other related sciences. According to geologists Roberto Hernández and Raúl Becchio, a vital part of the productive, scientific, and technological process involves the neutron irradiation of samples in the RA3 nuclear reactor at the Ezeiza Atomic Center (CAE), National Atomic Energy Commission (CNEA).
Fluid inclusions preserved in certain minerals are also fossilized samples that provide insight into the composition of the fluids that formed them, particularly their age, temperature, and pressure at formation, among other highly relevant data.
At the Late Andes SA laboratory, the composition of fluid inclusions is studied and determined using Raman spectrometry.
On another note, a mammoth preserved in the “eternal” ice of the Russian Arctic, in the Siberian permafrost, can be dated using carbon-14, opening up a vast array of opportunities to study its blood, semen, DNA, tissues, and so on. It is one of the most valuable time capsules bequeathed by nature. Another priceless record of time frozen in time is the fossilized footprints of long-extinct animals. One example is the dinosaur tracks widely distributed across the world’s Mesozoic terrains and very common in northern Argentina. They are like a snapshot captured on what were once ancient seashores and preserved forever in hard, solid rock. It is no different from an animal leaving its footprints on fresh pavement. These dinosaur tracks, or the bipedal, upright tracks of the Australopithecus proto-humans at Laetoli in Africa, allow us to observe and reconstruct the animal’s flexibility, agility, speed, height, weight, and other parameters through biometric calculations. Human time is a light-second between two nothingnesses. Time exists as long as the observer exists. The metaphor is that of time frozen in time: fossilized time—both the geological time preserved in rocks and the cosmological time frozen in dead stars. One can reflect on time in a thousand ways, one of them with feet on the Earth and eyes turned to the heavens. As the coat of arms of the National University of Tucumán states: Pedes in Terra ad Sidera visus.
Author: Dr. Ricardo Alonso
Publication date: April 9, 2017
Source: El Tribuno