1.3. Structural Forms of Lava

Like now what you see here is a kind of lava where we talk about the ‘Aa’ which is the basaltic lava which is characterized by a rough or a rubbly surface and these lava blocks also we actually extract the clinker from this kind of rough and rubbly surface lava is called ‘Aa’.

The 'Aa' lava is a type of basaltic lava known for its rough and jagged surface. This rough texture indicates that the lava cooled relatively quickly, trapping gas bubbles that create a blocky surface. When we talk about clinker, we refer to fragments of this tough, sharp lava that can be found in this type of flow. Understanding 'Aa' is crucial as it helps geologists study volcanic activity and the nature of lava flows.

Imagine walking on a gravel road; the stones and dirt are uneven and jagged just like 'Aa' lava. If you were to touch a freshly broken piece of an 'Aa' lava flow, it would feel very rough, similar to how walking on gravel feels under your feet.

This is a very smooth surface which is unbroken lava is also a basaltic lava that has a very smooth, billowy, undulating or a ropy surface and this is called a Pahoehoe and this is a Hawaiian meaning which is called smooth and unbroken lava.

Pahoehoe lava is another type of basaltic lava and is distinguished by its smooth and ropy surface. This texture forms when the lava flows slowly and retains its fluidity longer, allowing it to create waves and folds as it cools. The Hawaiian term 'Pahoehoe' reflects its origins in the Hawaiian Islands, where such lava is commonly found. This type of lava is significant in understanding the behavior of molten rock during an eruption.

Think of pouring warm syrup on a stack of pancakes. As the syrup flows, it creates smooth, wavy patterns. Similarly, Pahoehoe lava flows smoothly, creating its signature ropy appearance, which is both beautiful and scientifically intriguing.

When these kind of molten lava gets cooled up that is where it develops the structural forms whether structural joints are developed and some hollow spaces are also developed and this is where the hollow spaces becomes eventually man have made his shelters.

As molten lava cools, it solidifies and can develop structural features such as cracks or joints. These can create small hollow spaces within the rock, which are significant for both geological studies and human use. For example, these cavities can serve as natural shelters or areas for micro-ecosystems to thrive. Understanding how lava cools and structures itself helps scientists learn about volcanic landscapes and the environment.

Consider how ice cubes form in a tray. As water freezes, it solidifies and can develop cracks or air pockets. Similarly, as lava cools, it forms solid rock and can create cracks or holes, much like the patterns found in your ice cubes.

Now, what we can see is the layers of the horizontal layers of one over the another. So, these layers also talks about these beds which are talking about, so a set of lava have come down and gradually another set of lava and the by the time it cools down the another set came, another set came. So, this is how this horizontal layer started developing one over the another.

The concept of layered lava flows illustrates how successive eruptions deposit new layers of lava on top of older ones. Each layer represents a different flow event that solidified when it cooled, contributing to the geological history of a volcano. By studying these layers, geologists can infer the timing and characteristics of past eruptions.

Think of a birthday cake where each layer represents a different flavor. Just as you stack layers of cake on top of one another, layers of lava accumulate after each volcanic eruption. Each layer tells a story of the eruption that created it.

And this Tacheletic Basalt which is not a conducive rock for cave excavation as its chemical properties react sharply with moisture and disintegrate into pieces. The moment you are making an excavation process, it gradually brokes into small wedge-shaped pieces you know, that is one of the important aspect in the excavation challenges and excavation challenge especially with this kind of material.

Tacheletic Basalt poses significant challenges for excavation due to its properties. When exposed to moisture, this rock becomes unstable and breaks apart easily, complicating the excavation process. This is important for archaeologists and geologists as they may lose valuable structures or evidence during digs in areas with this type of basalt.

Imagine trying to dig in a wet sandcastle; as soon as water hits the sand, it crumbles and falls apart, making it difficult to shape anything new. Similarly, when working with Tacheletic Basalt, any moisture can cause the rock to disintegrate, making it challenging for excavation.

And you can see also as time passes on the spheroidal weathering takes place because this layers on the top layers keeps coming like a chip by chip and this is again in a spheroidal manner, this is called spheroidal weathering.

Spheroidal weathering refers to a geological process where rock layers undergo weathering in such a way that they become rounded over time. This occurs due to the gradual breakdown of the rock by environmental elements, creating a smooth, spherical surface. This process plays a vital role in shaping landscapes and can affect how rocks erode over time.

Imagine a piece of fruit, like an apple, that you leave outside over time. The apple's skin may start to soften and the edges become less sharp, ultimately leading it to a rounder shape. Similarly, rocks undergo spheroidal weathering, leading to smoother and more rounded surfaces.

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