Praktikum Geomorfologi 2021 Acara 4 - Bentuklahan Asal Proses Struktural

Summary

This geomorphology practical session focuses on structural landforms and their formation processes. The session explains the distinction between primary and secondary structures, highlighting the role of endogenous forces like tectonic movements in shaping the Earth’s surface. Key concepts include the formation of faults, folds, and various geological structures such as mesas, buttes, and mountains. Students are taught how to identify and classify structural landforms from spatial data, interpret geological maps, and understand their morphological characteristics. The practical includes identifying landform types such as anticlinals, synclinals, and fault-induced features, fostering a deeper understanding of Earth’s structural processes.

Takeaways

• 😀 Structural landforms are created by endogenous forces from within the Earth, which cause pressure on the Earth's crust, resulting in deformations like folding and faulting.
• 😀 There are two main types of geological structures: primary structures (formed during rock formation) and secondary structures (which form after the primary structures and influence Earth's surface morphology).
• 😀 Endogenous forces, such as plate movements, lead to stress in the Earth's crust, which can cause folding or faulting, depending on the type of stress applied (compression, tension, or shearing).
• 😀 Structural landforms can be classified into folds (formed by compression) and faults (formed by tension or shearing).
• 😀 Structural landforms are often characterized by a distinct resistance to erosion, which creates prominent features like ridges, valleys, and mountains.
• 😀 There are three main types of faulting: strike-slip faults (horizontal displacement), normal faults (vertical displacement due to tension), and reverse faults (caused by compression).
• 😀 Erosion plays a key role in transforming structural landforms over time, creating remnants like mesas, buttes, and isolated hills.
• 😀 The practical exercise involves identifying and mapping structural landforms based on topographic maps and images, paying attention to features like ridges, faults, and erosion patterns.
• 😀 Common examples of structural landforms in practice include grabens (caused by faults), and features like anticlinal and synclinal folds found in mountain ranges like the Zagros Mountains.
• 😀 The practical session requires students to create two tables: one for interpreting maps and images, and another to describe the characteristics of at least five structural landforms, including their relief, processes, and identifying features.

Q & A

What is the primary objective of this geomorphology practical session?

The primary objective is for students to understand and identify structural landforms formed by tectonic processes, and to explain their geomorphological features using spatial data.

What are structural landforms and how are they formed?

Structural landforms are landforms created by endogenic forces (internal Earth forces) that cause pressure on the Earth's crust, leading to folding or faulting of rocks. These processes are primarily due to tectonic forces.

What are primary and secondary structures in geomorphology?

Primary structures are formed during the rock formation process (such as sedimentation or magma cooling). Secondary structures occur after rock formation and include the geological features that influence the surface's morphology, such as faults and folds.

What is the difference between compression, tension, and shear forces?

Compression forces push rocks together, causing folding. Tension forces pull rocks apart, leading to faulting. Shear forces cause horizontal movement, which also results in faulting.

What are the different types of faults discussed in the session?

The types of faults include strike-slip faults (horizontal displacement), normal faults (due to tension or pulling apart), and reverse faults (due to compression or pushing together).

What is the significance of folds in the Earth's crust?

Folds are bends in the Earth's crust caused by compressive forces. They include anticlines (upward folds) and synclines (downward folds). These structures are crucial in understanding tectonic processes.

Can you explain what a 'graben' is?

A graben is a depression formed between two fault blocks, often resulting from tectonic forces that pull the Earth's crust apart. It is typically seen in regions experiencing active faulting.

How do erosion and tectonic processes interact to shape the landscape?

Erosion, combined with tectonic processes, transforms structural landforms over time. Tectonic processes like folding and faulting create initial landforms, which are then modified by erosion to create residual forms such as mesas and buttes.

What are the key characteristics used to identify structural landforms in maps and satellite images?

Key characteristics include sharp relief features, patterns in contour lines (such as straight or closely spaced lines), differences in rock resistance to erosion, and alignment of geological features like faults or folds.

What is the purpose of the two tables in the practical session?

The first table is for interpreting maps and satellite images to identify and label structural features, while the second table is for describing the characteristics of identified landforms, including their geological processes and structural features.