Mafic and felsic are terms used to describe the composition of igneous rocks. Mafic refers to rocks that are rich in magnesium and iron, while felsic refers to rocks that are rich in feldspar and silica. These two terms helps geologists classify and understand the different types of igneous rocks that exist. Mafic rocks are typically dark in color and have a high density. They are formed from magma that is rich in magnesium and iron, which gives them their characteristic dark color. Examples of mafic rocks include basalt and gabbro.
How does it relate to crystallisation and melting temperatures? Take a look at these two diagrams:
Melting this rock would result at first in melting of all three minerals together at 1270 C, even though their melting temperatures in isolation vary by around 500 C. This magma would first crystallise only forsterite, then it will crystallise forsterite and diopside together and eventually it will crystallise all three minerals together, until there is no more liquid.
Examples of mafic rocks include basalt and gabbro. On the other hand, felsic rocks are typically light in color and have a low density. They are formed from magma that is rich in feldspar and silica, which gives them their light color.
Mafic and loss
Mafic explosive eruptions of volatile-rich (arc) magmas are commonly characterized by pyroclasts that exhibit a much wider range in density and groundmass crystallinity than observed in silicic eruptions. This textural variation reflects the ability of low viscosity mafic melts to record syn-eruptive changes in conditions of gas loss and magma ascent. For this reason, textural studies of mafic pyroclasts may offer insight into conditions of magma ascent that are not recorded by silicic pyroclasts. However, such studies also raise important questions about eruption conditions of mafic magmas. First, variations in clast crystallinity within and between individual eruptive units suggest that these eruptions may involve magma withdrawal from complex magma storage systems Second, classification of mafic eruptions is often difficult because the deposit characteristics commonly record high (Plinian) intensities for modest (subPlinian) erupted volumes. Third, the fine ash component of many mafic explosive eruptions is poorly preserved, so that volume estimates are hindered by uncertainties about appropriate techniques for extrapolating beyond field exposures. Finally, many mafic pyroclasts are poorly to moderately vesicular, and most have bubble wall thicknesses that are anomalously large relative to silicic magmas, indicating that bubble-bubble interaction was not the primary cause of magma fragmentation. Additionally, clast morphologies that often include both fluidal and brittle forms suggest multiple simultaneous fragmentation mechanisms. Together these observations demonstrate that fragmentation of mafic magma is not easily explained by existing end member fragmentation models (brittle vs. ductile). More importantly, the low to moderate vesicularity of many mafic pyroclasts suggests rapid syn-eruptive gas segregation, which raises fundamental questions about the driving force for explosive mafic eruptions. This problem is most acute (and most puzzling) in rare mafic ignimbrites, such as the 30 km3 Villa Senni ignimbrite from Colli Albani, Italy. One possible explanation for protracted explosive eruption of low to moderate viscosity mafic magma lies in the role of deep-derived CO2, which may provide an additional external volatile propellant for magma acceleration and fragmentation.
Publication:
AGU Fall Meeting Abstracts
- 8428 VOLCANOLOGY / Explosive volcanism;
- 8434 VOLCANOLOGY / Magma migration and fragmentation;
- 8488 VOLCANOLOGY / Volcanic hazards and risks
Some examples of mafic rocks include:
Examples of felsic rocks include granite and rhyolite. The differences in composition between mafic and felsic rocks have important implications for their physical properties. For example, mafic rocks are generally more dense and have a higher melting point compared to felsic rocks. This means that mafic rocks are often found in the lower layers of the Earth's crust and are more resistant to melting during tectonic processes. Mafic and felsic rocks also have different mineral compositions. Mafic rocks typically contain minerals such as pyroxene, amphibole, and olivine, while felsic rocks contain minerals such as quartz and potassium feldspar. These differences in mineral composition can affect the hardness, durability, and chemical properties of the rocks. Understanding the differences between mafic and felsic rocks is important for geologists because it allows them to interpret the processes that formed these rocks and to reconstruct the geological history of an area. By studying the composition, texture, and distribution of mafic and felsic rocks, geologists can gain insights into the conditions that existed during their formation and the tectonic processes that shaped the Earth's crust..
Reviews for "The Implications of Mafic and Loss Rock Composition on Soil Fertility"
1. Samantha - 2 stars - I was really excited to read "Mafic and Loss" based on all the hype surrounding it, but I was ultimately disappointed. The story felt disjointed and lacked coherence. The characters were underdeveloped and it was hard to connect with them on any meaningful level. The pacing was also off, with certain parts dragging on while others felt rushed. Overall, I found it to be a confusing and unsatisfying read.
2. Jason - 2 stars - I had high expectations for "Mafic and Loss" after seeing all the positive reviews, but it just didn't live up to the hype for me. The writing style was overly descriptive and verbose, making it difficult to stay engaged with the story. Additionally, I found the plot to be predictable and lacking originality. The dialogue felt forced and unnatural, making it hard to believe in the characters and their interactions. Overall, this book fell short of my expectations and I wouldn't recommend it to others.
3. Emily - 1 star - I found "Mafic and Loss" to be incredibly boring and uneventful. The story seemed to go nowhere and lacked any significant plot developments. The characters were one-dimensional and lacked depth, making it hard to care about their fates. The writing style was also dry and lacked any sort of spark or excitement. I found myself forcing myself to finish the book, and even then, I was left unsatisfied. Overall, I would not recommend "Mafic and Loss" to anyone looking for an engaging and compelling read.