Geochem Assignment # 2 Mineral Evolution Article

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i have this article that need to be summarized based on specific criteria, reading it and understanding the subject of the article to focus on the important points in order to write a good summary, please follow the pdf attached exactly the same and cover every procedure. thanks

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Assignment #2 Mineral Evolution Intro Geochem Spring 2019 Due Tuesday 2/5 - START OF CLASS (no late assignments) Hazen, Robert M (2010) Evolution of Minerals. Scientific American, March 2010, 58-65 You will turn in your assignment at the beginning of class on discussion day. Bring an extra hard copy of your completed assignment – and of the paper - to class that day to help with the discussion. Note – It is critical that you avoid plagiarism while working on this. You should not be just pulling information from the paper, but you should understand it and turn it into your own thoughts. That may take more than 1 reading of the paper. 1. For each of the major time periods in Hazen (2010), summarize the following information in the table at the end of this assignment. Do NOT copy the information from the paper*, but summarize it in bullets or another abbreviated format. 2. To show how well you truly understand the different phases, write one tweet for each time period (for a total of 5) that summarizes the main point for that time period. For this assignment, limit yourself to the “classic” twitter rule of 140 characters. 3. The article discusses the processes that lead to redistribution of elements on the earth. In your own words, explain why that is important in this context. 4. The definition of a mineral requires that it be “inorganic”. Discuss that requirement in the context of this paper. Do you agree? Not agree? Your answer should be a well-constructed, thoughtful paragraph that illustrates both your opinion and some detail from the paper. 5. Put the paper into context by creating a conceptual timeline of these stages. You need to include the major time periods and how they are distinguished. You can do this by hand (it must be legible!) or using a computer. This is an opportunity to explore creative ways of explaining scientific concepts. This will be graded on originality, creativity, completeness & detail, and your ability to clearly communicate the concept. * That would be considered plagiarism, but you all know how to avoid that! Making Earth Why is it called this? Most important processes and/or events Example minerals Corresponding geologic time period(s) Black Earth Red Earth White Earth Green Earth GEOLOGY Evolution of Minerals BY ROBERT M. HA ZEN O KEY CONCEPTS ■ Only a dozen minerals (crystalline compounds) are known to have existed among the ingredients that formed the solar system 4.6 billion years ago, but today Earth has more than 4,400 mineral species. ■ Earth’s diverse mineralogy developed over the eons, as new mineral-generating processes came into play. ■ Remarkably, more than half of the mineral species on Earth owe their existence to life, which began transforming the planet’s geology more than two billion years ago. —The 58 Editors SCIENTIFIC AMERICAN nce upon a time there were no minerals anywhere in the cosmos. No solids of any kind could have formed, much less survived, in the superheated maelstrom following the big bang. It took half a million years before the first atoms— hydrogen, helium and a bit of lithium— emerged from the cauldron of creation. Millions more years passed while gravity coaxed these primordial gases into the first nebulas and then collapsed the nebulas into the first hot, dense, incandescent stars. Only then, when some giant stars exploded to become the first supernovas, were all the other chemical elements synthesized and blasted into space. Only then, in the expanding, cooling gaseous stellar envelopes, could the fi rst solid pieces of minerals have formed. But even then, most of the elements and their compounds were too rare and dispersed, or too volatile, to exist as anything but sporadic atoms and molecules among the newly minted gas and dust. By not forming crystals, with distinct chemical compositions and atoms organized in an orderly array of repeating units, such disordered material fails to qualify as minerals. Microscopic crystals of diamond and graph- ite, both pure forms of the abundant element carbon, were likely the first minerals. They were soon joined by a dozen or so other hardy microcrystals, including moissanite (silicon carbide), osbornite (titanium nitride), and some oxides and silicates. For perhaps tens of millions of years, these earliest few species —“ur-minerals”— were the only crystals in the universe. Earth today, in contrast, boasts more than 4,400 known mineral species, with many more yet to be discovered. What caused that remarkable diversification, from a mere dozen to thousands of crystalline forms? Seven colleagues and I recently presented a new framework of “mineral evolution” for answering that question. Mineral evolution differs from the more traditional, centuries-old approach to mineralogy, which treats minerals as valued objects with distinctive chemical and physical properties, but curiously unrelated to time — the critical fourth dimension of geology. Instead our approach uses Earth’s history as a frame for understanding minerals and the processes that created them. We quickly realized that the story of mineral evolution began with the emergence of rocky planets, because planets are the engines of minM a r c h 2 0 10 HOLLY LINDEM Looking at the mineral kingdom through the lens of deep time leads to a startling conclusion: most mineral species owe their existence to life w w w. S c i e n t i f i c A m e r i c a n . c o m SCIENTIFIC AMERICAN 59 [TIMELINE] Snapshots of Mineral Genesis I [THE AUTHOR] Robert M. Hazen, senior staff scientist at the Carnegie Institution’s Geophysical Laboratory and Clarence Robinson Professor of Earth Science at George Mason University, received his Ph.D. in earth science at Harvard University in 1975. He is author of 350 scientific articles and 20 books, including Genesis: The Scientific Quest for Life’s Origin, and he frequently presents science to nonscientists through radio, television, public lectures and video courses. Hazen’s recent research focuses on the role of minerals in the origin of life. The mineral hazenite, which is precipitated by microbes in the highly alkaline Mono Lake in California, is named after him. 60 SCIENTIFIC AMERICAN Making Earth 4.6 BILLION YEARS AGO: Millions of planetesimals form in the disk of dust and gas that W Zircon remains around the recently ignited sun (in background) and collide to form Earth (glowing planet). More than 200 minerals, including olivine and zircon, develop in the planetesimals, thanks to melting of their material, shocks from collisions, and reactions with water. Many of these minerals are found in ancient chondritic meteorites. W Olivine crystals in pallasite (meteorite) eral formation. We saw that over the past four and a half billion years Earth has passed through a series of stages, with novel phenomena emerging at each stage to dramatically alter and enrich the mineralogy of our planet’s surface. Some details of this story are matters of intense debate and will doubtless change with future discoveries, but the overall sweep of mineral evolution is well-established science. My colleagues and I are not presenting controversial new data or radical new theories about what occurred at each stage of Earth’s history. We are, rather, recasting the larger story of that history in the light of mineral evolution as a guiding concept. I do, however, want to emphasize one intriguing insight: most of Earth’s thousands of minerals owe their existence to the development of life on the planet. If you think of all the nonliving world as a stage on which life plays out its evolutionary drama, think again. The actors renovated their theater along the way. This observation also has implications for the quest to fi nd signs of life on other worlds. Sturdy minerals rather than fragile organic remains may provide the most robust and lasting signs of biology. Making Earth Planets form in stellar nebulas that have been seeded with matter from supernovas. Most of a nebula’s mass rapidly falls inward, producing the central star, but remnant material forms a X Chondrite ndrite (meteorite) vast rotating disk around the star. These hese leftovers progressively clump into larger ger and larger bits: sand-, pebble- and fi st-size t-size fluff balls of primordial dust harboring ring a limited repertoire of a dozen or so urminerals, along with other miscellaaneous atoms and molecules. Dramatic changes occur when the nascent star ignites and bathess the nearby concentrations of dust and gas with a refi ning fire. In our own solar system, stellar ignition occurred almost 4.6 billion years ago. Pulses of heat coming from the infant sun melted and remixed elements and produced crystals representing scores of new minerals. Among the crystalline novelties of this earliest stage of mineral evolution were the fi rst iron-nickel alloys, sulfides, phosphides, and a host of oxides and silicates. Many of these minerals are found in the most primitive meteorites as “chondrules”: chilled droplets of once molten rock. (These ancient chondritic meteorites also provide the evidence for the ur-minerals that predated chondrules. Mineralogists find the ur-minerals in the form of nanoscopic and microscopic grains in the meteorites.) In the ancient solar nebula, chondrules quickly clumped into planetesimals, some of which grew to more than 100 miles in diameter— large enough to partially melt and differentiate into onionlike layers of distinctive minerals, includM a r c h 2 0 10 COURTESY OF THE TEACHING COMPANY (Hazen); RON MILLER (illustrations); NATURAL HISTORY MUSEUM, LONDON (pallasite); ite); SCIENTIFICA Getty Images (zircon); MASSIMO BREGA Photo Researchers, Inc. (chondrite) n the 4.6 billion years since the solar system formed, the suite of minerals present has evolved from modest beginnings — about a dozen minerals in the presolar nebula — to better than 4,400 minerals found on Earth today. The planet has passed through a series of stages, represented at the right and in the following pages by five snapshots, involving a variety of mineral-forming processes. Some of these processes generated completely new minerals, whereas others transformed the face of the planet by turning former rarities into the commonplace. Black Earth BIOPHOTO ASSOCIATES Photo Researchers, Inc. (lepidolite); SCIENTIFICA Getty Images (beryl); JACANA Photo Researchers, Inc. (tourmaline) 4.4 BILLION YEARS AGO: The surface of lifeless Hadean Earth is largely black basalt, a rock formed from molten magma and lava. The next two billion years see about 1,500 minerals produced. Repeated partial melting of rock concentrates scarce, dispersed elements such as lithium (found in lepidolite), beryllium (in beryl) and boron (in tourmaline). Chemical reactions and weathering by the early oceans and the anoxic atmosphere also contribute. Minerals formed under high pressure, such as jadeite, are brought to the surface by plate tectonics. ing a dense, metal-rich core. Frequent collisions in the crowded solar suburbs introduced intense shocks and additional heat, further altering the minerals in the largest planetesimals. Water also played a role; it had been around from the beginning, as ice particles in the presolar nebula, and in the planetesimals these melted and aggregated in cracks and fissures. Chemical reactions with the resulting water generated new minerals. Perhaps 250 different mineral species arose as a consequence of these dynamic planet-forming processes. Those 250 minerals are the raw materials from which every rocky planet must form, and all of them are still found today in the diverse suites of meteorites that fall to Earth. W Tourmaline Black Earth Primordial Earth grew ever larger. Big planetesimals swallowed smaller ones by the thousands until only two major rivals remained in our orbital zip code, the proto-Earth and a much smaller Mars-size body sometimes known as Theia, after the mother of the Greek goddess of the moon. In a final paroxysm of unimaginable violence, Theia sideswiped the proto-Earth, vaporizing its outer layers and blasting 100 million trillion tons of incandescent rock vapors into space to become the moon. This scenario explains the high angular momentum of the Earth-moon system and many unusual features of the moon, including why its bulk composition matches that of Earth’s w w w. S c i e n t i f i c A m e r i c a n . c o m Repeated partial melting of granites concentrated rare “incompatible” elements. S Lepidolite X Beryll mantle (the nearly 2,000-mile-thick layer that extends from Earth’s iron-nickel core to the three- to 30-mile-thick crust at Earth’s surface). Following this moon-spawning collision about 4.5 billion years ago, the molten Earth began the cooling that continues to this day. Although Earth’s primitive surface included dozens of rare elements— uranium, beryllium, gold, arsenic, lead and many more— that were capable of forming a diverse assortment of minerals, Theia’s impact had served as a cosmic “reset.” It left Earth’s outer layers thoroughly mixed, with these less common elements far too dispersed to form separate crystals. Our planet was a desolate, hostile world, incessantly bombarded by nebular debris and largely covered by a veneer of black basalt, a kind of rock that is formed even in modern times when lava solidifies. Earth’s mineralogical diversity gradually increased through the aptly named Hadean eon (prior to about four billion years ago), primarily from repeated melting and solidifying of the rocky crust, as well as from weathering reactions with the early oceans and atmosphere. Over countless cycles, this partial melting and resolidifying of volumes of rock, and interactions between rock and water such as the dissolution of selected compounds, gradually concentrated uncommon elements enough to form new generations of exotic minerals. Not every planet possesses this great mineralSCIENTIFIC AMERICAN 61 Red Earth T Rhodonite In a geologic instant, photosynthesis by new kinds of algae brought about the Great Oxidation Event. 62 SCIENTIFIC AMERICAN forming formin potential. Tiny, dehydrated Mercury and Ea Earth’s equally dry moon became frozen before much melting could occur. Consequently, m we estimate that no more than about 350 differest ent mineral species will be found on those en worlds. Mars, with a modest water budget, w might have fared a little better as a result of m hydrous species such as clays and evaporite hyd minerals that form when oceans dry up. We esmine timate that NASA probes might eventually identify as many as 500 different minerals on the Red Planet. Pl Earth Ear is bigger, hotter and wetter and thus has other mineral-forming tricks to play. All the a few o rocky planets experienced volcanism that poured basalt across their surfaces, but Earth (and maybe Venus, which is about equal in size) had enough Venus inner heat to remelt some of that basalt to form a suite of igneous rocks called granitoids, including the familiar tan and gray granites of curbstones and countertops. Granites are coarse-grained blends of minerals, including quartz (the most ubiquitous grains of sand at the beach), feldspar (the commonest of all minerals in Earth’s crust), and mica (which forms shiny, sheetlike mineral layers). All these minerals were produced earlier in very small quantities in large planetesimals, but they first appear in great abundance in Earth’s geologic record thanks to the planet’s graniteforming processes. On Earth, repeated partial melting of gran- W Fossil stromatolite cross section X Turq Turquoise ise ites concentrated rare “incompatible” elements that are unable to find a comfortable crystallographic home in common minerals. The resulting rocks feature more than 500 distinctive minerals, including giant crystals of species rich in lithium, beryllium, boron, cesium, tantalum, uranium, and a dozen other rare elements. It takes time — some scientists estimate more than a billion years — for these elements to achieve mineral-forming concentrations. Earth’s planetary twin, Venus, may have been sufficiently active for long enough to progress this far, but neither Mars nor Mercury has yet revealed significant surface signs of granitization. Earth gained even more mineral diversity through the planetary-scale process of plate tectonics, which generates fresh crust along chains of volcanoes, while old crust is swallowed up in subduction zones, where one plate slips under another and is returned to the mantle. Immense quantities of wet, chemically diverse rocks subducted from the crust were partially melted, causing further concentration of scarce elements. Hundreds of new minerals were produced in massive sulfide deposits, which today provide some of Earth’s richest bodies of metal ore. Hundreds more mineral species first appeared at Earth’s surface when tectonic forces uplifted and exposed deep rock domains with their hoard of distinctive minerals that form under high presM a r c h 2 0 10 RON MILLER (illustrations); SCIENTIFICA Getty Images (rhodonite); TED KINSMAN Photo Researchers, Inc. (stromatolite); E. R. DEGGINGER Photo Researchers, Inc. (turquoise) 2 BILLION YEARS AGO: Photosynthetic living organisms have given Earth’s atmosphere a small percentage of oxygen, dramatically altering its chemical action. Ferrous (Fe2+) iron minerals common in black basalt are oxidized to rust-red ferric (Fe3+) compounds. This “Great Oxidation Event” paves the way for more than 2,500 new minerals, including rhodonite (found in manganese mines) and turquoise. Microorganisms (green) lay down sheets of material called stromatolites, made of minerals such as calcium carbonate. White Earth COURTESY OF ALAN JAY KAUFMAN (cap carbonate); TED KINSMAN Photo Researchers, Inc. (kaolinite); SCIENCE SOURCE Photo Researchers, Inc. (snow crystal) 700 MILLION YEARS AGO: Climate change covers the entire planet surface with one e mineral — ice — for millions of years. Eventually carbon dioxide from volcanoes triggers runaway global warming, and the planet cycles between hothouse and snowball. In the hothouse phases, weathering adds large quantities of fi negrained clay minerals such as kaolinite to the landscape. Distinctive “cap carbon-ate” layers deposited in shallow, warming oceans include crystals six feet tall. sure, such as jadeite (one of two minerals better known as the gemstone jade). All told, perhaps 1,500 different minerals found on or near Earth’s surface might have been generated by dynamic crust and mantle processes during Earth’s first two billion years. But mineralogists have catalogued more than 4,400 different mineral species. What happened to triple Earth’s mineralogical diversity? Red Earth The answer is life. The biosphere distinguishes Earth from all other known planets and moons, and it has irrevocably transformed the nearsurface environment— most conspicuously the oceans and atmosphere but also the rocks and the minerals. Life’s earliest manifestations— primitive single-celled organisms that “fed” on the chemical energy of rocks — cannot have had much effect on Earth’s mineralogical diversity. To be sure, geologists have found biologically mediated rock formations dating back to 3.5 billion years ago, including reefs made of calcium carbonate and so-called banded iron formations (in which iron oxides apparently lock away the fi rst oxygen produced by life). But the land was still barren, the atmosphere at large still lacked oxygen, surface weathering was slow, and the earliest life contributed almost nothing to alter the number of minerals present or their distribution. w w w. S c i e n t i f i c A m e r i c a n . c o m S Cap carbonate S Kaolinite X Ice That situation changed d iin a geologic l i iinstant with the rapid ri ...
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The mineral revolution
Students Name
University Affiliation



Making Earth

Why is it
called this?

➢ It is the

Black Earth

➢ The earth is


Red Earth

➢ The earth is

White Earth

Green E

➢ The earth is

➢ The

process of the

covered in black

red due to

covered in


formation of

basaltic rock





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