GEOLOGI DASAR: LIMA HUKUM DASAR GEOLOGI - Video Kuliah Pembelajaran Daring Kolaboratif

Summary

In this educational lecture, the fundamental laws of geology are explored, crucial for understanding geological processes. These laws include the Principle of Uniformitarianism, which posits that current geological processes are key to understanding the past, the Law of Original Horizontality, suggesting that rock layers were initially flat, and the Law of Superposition, indicating that the oldest rocks are at the bottom. Also discussed are the Principle of Crosscutting Relationships, which helps determine the relative ages of rock layers, and the Principle of Faunal Succession, which uses fossils for correlation. These laws are essential for studying the Earth's history and predicting future geological events.

Takeaways

• 📚 The fundamental laws of geology are crucial for understanding geological processes and the formation of rocks over time.
• 🔍 The Law of Uniformitarianism suggests that the geological processes active today were also active in the past, allowing us to predict future geological changes based on past events.
• 🌊 The Law of Original Horizontality posits that rock layers were originally deposited horizontally, with exceptions due to tectonic forces or erosion.
• 📈 The Law of Superposition states that in an undisturbed sequence of rock layers, the oldest layers are at the bottom and the youngest at the top.
• ✂️ The Principle of Crosscutting Relationships indicates that a geological feature that cuts across other layers is younger than the layers it cuts through.
• 🐚 The Principle of Faunal Succession, introduced by William Smith, uses the presence of fossils in rock layers to correlate and date geological strata across different regions.
• 🏔️ The script discusses how the discovery of coral fossils in the Himalayas suggests that the region was once an ocean floor, illustrating the application of the Law of Uniformitarianism.
• 🌐 The concept of continental drift is mentioned, with the idea that continents were once joined and may come together again in the future, reflecting geological changes over time.
• 🏞️ The Grand Canyon is used as an example to illustrate how rock layers that were initially horizontal can be tilted or deformed due to tectonic forces.
• 🌋 The script also touches on the idea that geological processes like erosion and intrusion can alter the original position and appearance of rock layers.

Q & A

What is the significance of basic geological laws in the study of geology?

Basic geological laws are fundamental for understanding the formation, arrangement, and relationships between rocks in both space and time. They provide the foundation for studying geological processes and interpreting Earth's history.

What is the Law of Uniformitarianism in geology?

The Law of Uniformitarianism states that the geological processes occurring today are the same as those that happened in the past. This principle, summarized as 'the present is the key to the past,' helps geologists predict future geological events by studying past occurrences.

Can you provide an example of the Law of Uniformitarianism?

An example is the presence of coral limestone found at the summit of the Himalayas, indicating that this area was once underwater in the distant past, similar to how coral reefs form in modern oceans.

What does the Law of Original Horizontality state?

The Law of Original Horizontality states that layers of sediment are originally deposited horizontally. If rock layers are found tilted or folded, it indicates that tectonic forces deformed them after their deposition.

What does the Law of Superposition describe?

The Law of Superposition explains that in an undisturbed sequence of rock layers, the oldest layers are at the bottom, while the youngest layers are at the top.

How can the Law of Superposition help in determining the age of rocks?

By examining the order of rock layers, geologists can identify which layers are older and which are younger, helping them build a chronological sequence of geological events.

What is the Principle of Crosscutting Relationships?

The Principle of Crosscutting Relationships states that if one geological feature cuts across another, the feature that has been cut is older. The cutting feature is always younger than the rock it intrudes.

Can you provide an example of the Principle of Crosscutting Relationships?

If a fault or igneous intrusion cuts through several rock layers, the fault or intrusion is younger than the layers it disrupts. For example, an igneous intrusion within sedimentary layers would be younger than the layers it penetrates.

What is the Principle of Faunal Succession in geology?

The Principle of Faunal Succession states that fossils within rock layers follow a specific, predictable order. This allows geologists to correlate rock layers across different regions based on the fossils they contain.

How does the Principle of Faunal Succession assist in geological correlation?

By comparing fossil content across different rock outcrops, geologists can establish a correlation between them, determining that they were formed during the same geological time period based on shared fossil species.

Outlines

00:00

📚 Basic Principles of Geology

This paragraph introduces the fundamental laws of geology, which serve as the cornerstone for understanding geological processes. It discusses the importance of these principles in interpreting the arrangement, order, and relationships of rock formations in space and time. The laws covered include the Law of Uniformitarianism, which posits that present geological processes are the key to understanding past geological events, thereby allowing predictions about future geological changes. The paragraph also mentions the Law of Original Horizontality, which states that the initial position of rock layers is horizontal unless influenced by tectonic forces that cause deformation. Examples such as the formation of coral reefs at the base of the Himalayas are used to illustrate these principles.

05:03

🗺️ Principles of Superposition and Crosscutting Relationships

This paragraph delves into the Law of Superposition, which states that in an undisturbed sequence of rock layers, the oldest rocks are at the bottom and the youngest at the top. It uses visual examples to demonstrate how rock layers can be identified and ordered based on their position relative to one another. The principle of crosscutting relationships is also explained, which states that any rock formation that cuts across other layers must be younger than the layers it intersects. The paragraph provides examples of how these principles can be observed in nature, such as intrusions and folding that disrupt the original horizontal alignment of rock layers. It emphasizes the importance of these principles in reconstructing geological history and understanding the relative ages of rock formations.

🐚 Faunal Succession and Geological Correlation

The final paragraph focuses on the principle of faunal succession, which is based on the observation that certain fossils appear in specific sequences within rock layers. This principle, attributed to William Smith, allows for the correlation of rock layers across different areas based on the presence of identical fossil assemblages. The paragraph explains how the presence of similar fossils in different rock formations can be used to infer a correlation, indicating that these rocks were formed during the same time period. Examples are given to illustrate how the identification of specific fossils, such as gastropods, crinoids, and ammonites, can be used to correlate rock layers and build a more comprehensive understanding of geological history.

Keywords

💡Geology

Geology is the scientific study of the Earth's physical structure, substances, history, and the processes that act on it. In the video, geology serves as the overarching field of study, where fundamental laws about the formation and interaction of rocks over time and space are discussed.

💡Law of Uniformitarianism

This law states that the present is the key to the past, meaning that geological processes happening today, like erosion or sedimentation, also occurred in the past in the same way. It helps predict future geological changes by studying past events. In the video, the example of coral limestone found on the Himalayas is used to explain how these mountains were once seabeds.

💡Law of Original Horizontality

This law states that layers of sediment are originally deposited horizontally under the action of gravity. It explains that if rock layers are found tilted or folded, they have been disturbed after their formation. The video uses a diagram of rock layers to show how they are laid flat initially but can be deformed by tectonic forces.

💡Law of Superposition

This principle asserts that in any undisturbed sequence of rock layers, the oldest layer is at the bottom, and the youngest is at the top. The video illustrates this law by showing different colored rock layers, with the oldest being at the base and the youngest at the top.

💡Principle of Crosscutting Relationships

This principle states that any geological feature that cuts through another is younger than the feature it cuts. The video gives an example of a rock intrusion cutting through other layers, making the intrusion younger than the rocks it disrupts.

💡Principle of Faunal Succession

This principle states that layers of sedimentary rock contain fossilized flora and fauna, and these fossils succeed one another vertically in a specific, reliable order that can be used to identify the relative age of the layers. The video discusses how fossils in different layers can be used to correlate rock formations between different regions.

💡Tectonic Deformation

Tectonic deformation refers to the bending, breaking, and movement of Earth’s crust due to tectonic forces, leading to features like faults and folds. In the video, the speaker mentions how horizontal rock layers can be tilted or folded due to tectonic deformation.

💡Intrusion

An intrusion is when molten rock from beneath the Earth's surface forces its way into existing rock layers, creating a new formation. The video shows intrusions as younger features that cut through older rock layers, following the principle of crosscutting relationships.

💡Fossil Correlation

Fossil correlation involves using the fossils in different rock layers to establish a relative timeline and connect geographically distant rock formations. The video provides examples of how identical fossils found in different regions indicate that those layers were formed during the same geological period.

💡Pangea

Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, before breaking apart into the continents we know today. The video briefly mentions how the Earth’s landmasses, which were once part of Pangea, continue to move apart due to tectonic activity.

Highlights

Basic geological laws are fundamental in understanding the science of geology.

The concept of spatial and temporal relationships among rock formations is crucial.

Law of Uniformitarianism suggests that present processes are the key to understanding past geological events.

The principle 'the present is the key to the past' implies that future geological events can be predicted by studying past ones.

Example of Uniformitarianism: Coral reefs found at the base of the Himalayas indicate a past oceanic environment.

Law of Original Horizontality states that the initial position of rock layers is horizontal unless deformed.

Deformation of rock layers, such as tilting, is due to tectonic forces.

Law of Superposition indicates that the oldest rocks are at the bottom and the youngest at the top in undisturbed sequences.

Principle of Crosscutting Relationships states that an intrusion that cuts across rock layers is younger than the layers it cuts.

Fossil evidence is used to correlate rock layers across different areas.

Principle of Faunal Succession, proposed by William Smith, uses the presence of fossils to determine the relative age of rock layers.

Fossils provide a record of evolution and can be used to correlate rock layers across different regions.

Geological laws help predict the future geological events based on the understanding of past events.

The concept of Pangea and its breakup is explained through the geological time scale.

The Grand Canyon serves as an example of rock layers that were originally horizontal but have been tilted due to tectonic forces.

The importance of understanding the original position of rock layers and their deformation is emphasized.

The sequence of rock layers in the geological column is used to determine the relative age of rocks.

The practical application of geological laws in understanding the Earth's history and predicting future geological changes.

Transcripts

[Musik]

[Musik]

halo sampai jumpa lagi dalam Kuliah 5

hukum dasar geologi yang akan dibahas

pada hari ini

ya Nah dalam ilmu geologi huk hhukum

dasar geologi sangatlah penting dan

merupakan dasar dalam mempelajari ilmu

geologi nah hukum geologi ini menjadi

acuan dan dalami antara lain adalah

konsep tentang susunan aturan dan

hubungan antar batuan dalam ruang dan

waktu sedangkan pengertian ruang dalam

geologi ini adalah tempat di mana batuan

itu terbentuk dan pengertian waktu

adalah waktu pembentukan batuan dalam

skala geologi nah hukum dasar teologi

yang kita pelajari di sini ada lima

yaitu Law of

uniformitarianism Law of original

horizontality kemudian Law of

superposition kemudian yang keempat

principle of crosscutting relationship

dan yang kelima adalah principle of

faunal

succession nah hukum yang pertama Law of

UN formitarianism atau hukum

uniformitarianisme adalah hukum yang

menyatakan bahwa keadaan sekarang ini

adalah kunci ya Bagi keadaan masa lalu

sehingga disebut dengan the present is

the to the past artinya apa

proses-proses geologi yang terjadi saat

ini juga terjadi pada masa

lampau maka dari itu sebenarnya masa

depan dapat diprediksi dengan melihat

apa yang terjadi pada masa lampau itu

sendiri

contohnya pada saat ini dasar laut

tumbuh batu gamping Koral Jadi kalau

pada saat ini puncak pegunungan Himalaya

itu dijumpai batu gamping Koral maka di

sini dapat disimpulkan bahwa pada zaman

yang lalu di daerah pegunungan Himalaya

itu juga merupakan dasar laut nah hal

ini dicetuskan oleh Jameson dan juga

dipopulerkan oleh Charles l dalam

bukunya princip of Geologi ya ini bisa

kita lihat pada zaman pem Itu posisinya

benua pangeanya penuh tapi di zaman

Trias ini sudah mulai terpecah-pecah ya

kemudian di zaman Yura maka benua ini

juga pecahnya makin lebar dan pada saat

zaman

ee kapur ini juga sangat besar dan yang

terjadi pada saat ini semua benua hampir

berjauh nah suatu saat kemungkinan ee

itu benowa Pangea akan bersatu kembali

gitu ya Nah yang kedua hukum original

horizontality di mana hukum ini

menyatakan kalau kedudukan awal dari

satu pengendapan lapisan batuan itu

adalah horizontal karena apa wadahnya

dasarnya adalah horizontal kecuali kalau

pada tepi cekungan yang memiliki sudut

miring ya toh kemiringannya asli atau

inisal Dep maka dia memang nanti

bentuknya akan cekung karena dasar

cekungannya memang menyudut Nah kalau

kalian bisa lihat gambar ini ya

pertama-tama itu ini datar datar

datardatar karena adalah horizontal

tetapi karena tempat mangkoknya ini eh

cekup maka bagian tepi ini akan

mengikuti wadahnya gitu ya Nah kalau

sekarang dijumpah BATAN dengan kedudukan

lapisan miring berarti batuan tersebut

sudah dipengaruhi oleh deformasi gaya

tektonik nah ini kita bisa lihat ini

awalnya mendatar kemudian dia miring

karena wadahnya memang miring seperti

ini Kalaupun dia suatu saat tererosi

maka kemiringan ini masih

sama kemudian ini juga contoh di Grand

Canyon ini awalnya adalah horizontal

tetapi saudara bisa melihat di

sampingnya ini ini sudah eh miring ya

atau menyudut seperti ini ya sampai di

sini jelas ya oke kemudian yang

ketiga Law of superposition atau hukum

superposisi hukum ini diusulkan oleh

steno dan James hton dengan bunyi pada

sekuen lapisan yang belum terganggu ya

batuan yang tertua atau yang terendapkan

paling awal akan berada paling bawah

jelas ya Jadi yang awal itu ya baw bawah

gitu ya dan batuan yang termuda atau

yang terendapkan paling akhir itu akan

berada di paling atas atau the lower is

the older the upper is The younger Nah

saudara bisa melihat di sini ada gambar

yang merah ini adalah batuan yang tertua

karena dia diendapkan paling awal

sedangkan yang kuning ini adalah yang

paling muda gitu ya

Oke ini adalah jimen zaman lamp

bisa kita lihat

ee beliaunya cukup profesional ganteng

ya Nah ini contohnya juga hukum

superposisi ini di sini kalau saudara

bisa lihat eh lapisan yang pertama ini

paling tua kemudian eh di time kedua

yang kedua ini time ketiga seperti ini

time keempat seperti ini ya yang time

kelima maka yang lima atau warna apa ini

abu-abu atau ungu ya ini adalah yang

termuda demikian juga kalau satu batuan

suatu saat dia mengalami lipatan atau

ada gaya tektonik maka dia akan bisa

tertekan atau bahkan eh berputar itu

jangan lupa nanti tetap harus kita

mendeskripnya secara superposisi

kemudian hukum yang keempat adalah

principle of crosscutting relationship

apabila terdapat penyebaran lapisan

batuan atau satuan lapisan batuan di

mana salah satu dari lapisan tersebut

memotong lapisan yang lain maka satuan

batuan yang memotong ini umurnya relatif

lebih muda daripada satuan batuan yang

dipotong jadi jelas ya yang memotong itu

kan pasti sudah ada yang dipotong gitu

ya jadi yang memotong itu pasti lebih

mudan ini contohnya Ini nomor satu yang

merah ini tua kemudian diendapkan hijau

diindapkan abu-abu kemudian ada intrusi

ya yang nomor empat ini kemudian baru

nanti yang paling mudah adalah lma atau

ini gambar yang di sebelah ini ada

lapisan 1 2 3 4 kemudian dia diintrusi

maka inilah yang paling mudah jelas ya

sampai di sini ini contoh ada lapisan

batuan kemudian di ada sesar maka sesar

ini adalah yang muda kemudian ini ada

juga contohnya lagi ini e yang paling

bawah c yang kemudian hitam kemudian

diendapkan yang B atau kuning kemudian

ada intrusi ya D kemudian baru

diendapkan a ini yang paling muda adalah

yang a ya yang paling tua adalah e nah a

dengan D ini yang tua adalah D ya karena

dia eh

setelahelakukan intrusi maka dia

terendahkan a gitu ya oke kemudian hukum

yang terakhir atau yang kelima itu

adalah prinsip

di sini Bapak William Smith atau

bapakarah mengamati lapisan Batan yang

dapat diinenasi dengan fosil yang

terkandung ya disebutkan karena adanya

evoluasi berbagai fosil yang terawetkan

di dalam satu sekuen batuan penampakan

fisiknya bisa berubah karena waktu bisa

juga digunakan untuk melakukan korelasi

antar daera ini bisa lihat kita lihat

ada singkapan yang pertama ini adalah

singkapan yang kedua maka kita temukan

fosil yang sama maka dapat ditarik

kesimpulan korelasi Oke ini contoh yang

kedua kita lihat fosilnya yang sama ini

juga akan kita tarik sebagai korelasi

kemudian ini eh di singkapan yang ada 1

2 3 ini juga sama kita akan bisa melihat

Apakah ditemukan gastropoda Apakah

krinoid apa Koral apa amonit maka

Saudara akan bisa menarik sebagai

korelasi demikian apa yang saya

sampaikan lima hukum dasar geologi bisa

dipakai sebagai tambahan ilmu untuk

kilobi dasar Terima kasih selamat siang

asalamualaikum warahmatullahi

wabarakatuh