Geochemistry Assignment

Geochemistry Assignment






Geochemistry Assignment

  1. Definition of terms

Stellar Ignition refers to heat from the infant sun melting and mixes with other elements and produce crystals that symbolize scores of new minerals. It is the early stage of mineral evolution where a mixture of elements like sulfides, iron-nickel and silicates are produced (Hazen, 2010).

Chondritic meteorites refer to complex aggregations of calcium-aluminum-rich inclusions, chondrules and amoeboid olivine aggregates as well as other refractory objects with a fine-grainedd matrix dust and of mineral grains (Hazen et al., 2008).

ur-minerals is a dozen species that is the starting point of any mineral evolution where it marks a variety of bond types like the metallic bonds, covalent bonds and ionic bonds interactions. Moreover, they include structural motifs such as magnesium polyhedral coordination, aluminium and silicon which are common to many to rock forming phases (Hazen et al., 2008).

Theia is a smaller Mars-sized body named after Greek goddess of the moons’ mother. It is formed after big planetesimals swallow the smaller ones until only two remains, one of which is Theia and proto-Earth (Hazen, 2010).

Mineral evolution suggests that moons mineralogy and terrestrial planets evolves due to different physical, biological and chemical processes that led to the formation of new mineral types (Hazen et al., 2008).

  1. What processes over earth’s history lead to mixing and redistribution of the elements on earth?

According to Hazen et al. (2008), the various processes that lead to the redistribution and mixing of the earth’s elements include such as the pre-stellar “dense” molecular clouds. This process involved the basis of mineral evolution as it resulted in particles with some oxides, nitrides, silicates and carbides. Another process involved repeated chemical and physical processing of elements in the upper and crust-mantle. The other process that accounts for mineral evolution involves geo-biosphere co-evolution and biological activity.


  1. Why would you expect there to be fewer varieties of minerals on Mercury or the moon? Are those two the same?

There are fewer varieties of minerals on Mercury and the Moon due to the igneous events which represent the mineral evolution of relatively small volatile poor terrestrial bodies. The near surface mineralogy of Mercury and moon is essentially frozen which is caused by the bombardment by the micrometeorites and the effects of solar wind particles. The two are not the same but are formed from the same process of crystallization of igneous rocks,(Hazen et al. 2008) p. 1699


  1. The author refers to Black Earth, Red Earth, White Earth, and Green Earth – how do these differ? What critical processes or settings define each of these? Which minerals came into being in each of these?

According to Hazen et al. (2008), the various earth types differ by the time they appeared on the earth surface and what they had to cover the earth with. Black earth appeared 4.4 billion years ago and covered the earth with black basalt-a rock formed from molten magma and lava and is characterized by partial melting of rocks. Some of the minerals found in black earth include such as boron, tantalum, cesium, lithium and uranium. Red earth appeared 2 billion years ago and covered the earth with photosynthetic living organisms. The red earth is characterized by the great oxidation event due to alteration of chemical action by oxygen added by the organisms mentioned above. It comprises of minerals such as calcium carbonate, turquoise, and rhodonite. White Earth appeared 700 million years ago and covered the earth surface with climate change with ice for many years. The white earth is characterized by cap carbonate that resulted from volcanic activities. It comprises of minerals such as kaolinite.Lastly, Green Earth appeared 400 million years ago, and the earth was full of multicellular organisms and plants. The green earth comprises of minerals such as calcite, hazenites, and aragonite

  1. This – and other papers – refer to the “co-evolution of the geo- and biospheres”. Explain what this means and why it is important to mineral evolution.


Co-evolution of the geo- and biospheres refers to the reciprocal change in abundance, composition and diversity between the organisms present and their fossils and the type of minerals that are found in a specific region. Moreover, geo-biosphere co-evolution refers to the change of geologic composition due to changes in adaptation mechanisms of animals such as the development of shells. According to Hazen et al. (2008), the importance of geo-biosphere co-evolution is that microorganisms can result in the formation of new as well as alteration of composition of existing minerals to form new ones.


  1. The two papers are written for different audiences. Find a piece of information included in both papers and compare the language, wording, and detail. Here is a rare occasion when you can copy the exact words – just be sure to include them in quotes with a proper citation. An example citation………. Hazen et al. (2008) p. 1703.   Please write a few sentences comparing the styles of the journals and their likely audiences.


The introduction of the journal by Hazen and colleagues is aimed at expert audiences who have more than the basic knowledge of mineralogy. This inference follows from the wording of the journal that uses professional terminology such as mineralogical diversity, micro- and macroscopic solid phases and crustal depths. The following section gives the introduction of this journal:

“Earth today boasts about 4300 known species of minerals, with as many as 50 new types being identified each year (e.g., Yet the mineralogical diversity now found at or near Earth’s surface, defined here as micro- or macroscopic solid phases (>1 µm diameter) at crustal depths less than about 3 km…” (Hazen et al., 2008, p. 1693).

On the contrary, the following section is the introduction by Hazen:

“Once 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 fi rst supernovas, were all the other chemical elements synthesized…” (2010, p. 58)

This section indicates that Hazen was targeting an audience who are not informed in the matters of mineralogy. This inference follows from the introduction in which Hazen starts by familiarizing the audience with the genesis of minerals in the form of a story and the use of “giant stars” in his explanation.




Hazen, R. M. (2010). Evolution of minerals. Scientific American302(3), 58-65.

Hazen, R. M., Papineau, D., Bleeker, W., Downs, R. T., Ferry, J. M., McCoy, T. J., … & Yang, H. (2008). Review Paper. Mineral evolution.American Mineralogist93(11-12), 1693-1720.

Looking for this or a Similar Assignment? Click below to Place your Order Instantly!