Introduction stratigraphy

Stratigraphy, a branch of geology, studies rock layers and layering (stratification). Stratigraphy, from Latin stratum + Greek graphia, is the description of all rock bodies forming the Earth's crust and their organization into distinctive, useful, mappable units based on their inherent properties or attributes in order to establish their distribution and relationship in space and their succession in time, and to interpret geologic history. Stratum (plural=strata) is layer of rock characterized by particular lithologic properties and attributes that distinguish it from adjacent layers.

History of stratigraphy begin by Avicenna (Ibn Sina) with studied rock layer and wrote The Book of Healing in 1027. He was the first to outline the law of superposition of strata:^[1] "It is also possible that the sea may have happened to flow little by little over the land consisting of both plain and mountain, and then have ebbed away from it. ... It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that some mountains appear to have been piled up layer by layer, and it is therefore likely that the clay from which they were formed was itself at one time arranged in layers. One layer was formed first, then at a different period, a further was formed and piled, upon the first, and so on. Over each layer there spread a substance of differenti material, which formed a partition between it and the next layer; but when petrification took place something occurred to the partition which caused it to break up and disintegrate from between the layers (possibly referring to unconformity). ... As to the beginning of the sea, its clay is either sedimentary or primeval, the latter not being sedimentary. It is probable that the sedimantary clay was formed by the disintegration of the strata of mountains. Such is the formation of mountains."

The theoretical basis for the subject was established by Nicholas Steno who re-introduced the law of superposition and introduced the principle of original horizontality and principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment.

The first practical large scale application of stratigraphy was by William Smith in the 1790s and early 1800s. Smith, known as the Father of English Geology, created the first geologic map of England, and first recognized the significance of strata or rock layering, and the importance of fossil markers for correlating strata. Another influential application of stratigraphy in the early 1800s was a study by Georges Cuvier and Alexandre Brongniart of the geology of the region around Paris.

In the stratigraphy you can find term of

- Stratigraphic classification. The systematic organization of the Earth's rock bodies, as they are found in their original relationships, into units based on any of the properties or attributes that may be useful in stratigraphic work.

- Stratigraphic unit. A body of rock established as a distinct entity in the classification of the Earth's rocks, based on any of the properties or attributes or combinations thereof that rocks possess. Stratigraphic units based on one property will not necessarily coincide with those based on another.

- Stratigraphic terminology. The total of unit-terms used in stratigraphic classification.It may be either formal or informal.

- Stratigraphic nomenclature. The system of proper names given to specific stratigraphic units.

- Zone.Minor body of rock in many different categories of stratigraphic classification. The type of zone indicated is made clear by a prefix, e.g., lithozone, biozone, chronozone.

- Horizon. An interface indicative of a particular position in a stratigraphic sequence. The type of horizon is indicated by a prefix, e.g., lithohorizon, biohorizon, chronohorizon.

- Correlation. A demonstration of correspondence in character and/or stratigraphic position. The type of correlation is indicated by a prefix, e.g., lithocorrelation, biocorrelation, chronocorrelation.

- Geochronology. The science of dating and determining the time sequence of the events in the history of the Earth.

- Geochronologic unit. A subdivision of geologic time.

- Geochronometry. A branch of geochronology that deals with the quantitative (numerical)measurement of geologic time. The abbreviations ka for thousand (103), Ma for million (106), and Ga for billion (milliard of thousand million, 109) years are used.

- Facies. The term "facies" originally meant the lateral change in lithologic aspect of a stratigraphic unit. Its meaning has been broadened to express a wide range of geologic concepts: environment of deposition, lithologic composition, geographic, climatic or tectonic association, etc.

- Caution against preempting general terms for special meanings. The preempting of general terms for special restricted meanings has been a source of much confusion.

SEISMIC HAZARD ASSESSMENT:In the Case Study of Minesite Area-Central Kalimantan

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Dec 2004, Bandung

SEISMIC HAZARD ASSESSMENT:In the Case Study of Minesite Area-Central Kalimantan

Engkon K.Kertapati

Geological Research and Development Centre

Abstract

The low-seismicity Central Kalimantan has never experienced any earthquake damage. Thus, earthquake-resistant design has not been specifically required in the building codes. However, it has been realized that urban and mine areas located rather distantly from earthquake sources may also be affected by tremors. The key is basically determined by how well seismic hazards derived from seismic potency can be estimated. In this paper, the potential ground motion in terms of the peak ground accelerations ( PGAs) due to long – distance East Kalimantan and West Sulawesi earthquakes ( far field earthquake ) is investigate, following a probabilistic seismic hazard assessment approach. Earthquakes that have occurred in radius of 500 km ( far field ) in the last 50 year are used. Based on the PGAs of more than 50 % East Kalimantan and West Sulawesi earthquakes recorded in Central Kalimantan, the attenuation relationship of Fukushima and Tanaka ( 1992 ) is found to correlate well with the high-rate attenuation characteristic of the region. The predicted design basis PGA for Tailings Dam , i.e. PGA with 10 % probability of being exceeded in a 50-year exposure time, on rock out-crops site is 0.041 g ( g = gravity value ), or 0.103 g on soft soil. And 0.105 g with 10 % probability of being exceeded in a 1000 year exposure time on rock out-crops or 0.261 g for soft soil. However, the increasing number of felt tremors in recent years demonstrates such as: Muarateweh Earthquake, which occurred on July 05, 1996, that although no significant damage was report, the earthquake was strongly felt.

Keywords: ground acceleration, ground-motion, attenuation function, earthquake- resistant design

LANDSLIDE IN KEBUMEN TERITORY SOUTH PART CENTRAL JAVA

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

LANDSLIDE IN KEBUMEN TERITORY
SOUTH PART CENTRAL JAVA

Eko Soebowo, Herryal Z. Anwar, Dwikorita Karnawati

Pusat Penelitian Geoteknologi – LIPI

Abstract

Kebumen Region and others Southern Part of Central Java have a long history on landslide hazard occurrences. Landslides in this area are influenced by the litological condition, morphology, structure, hidrology, rainfall and others factor. Therefore, landslides potential area information is primarily important to design the effective mitigation system. Engineering geological study which has been done in this area indicate that landslides distribution concentrate mainly at Ayah-Karangbolong-Alihan-Rowokele area, at litological unit of weathered volcanic breccia with structures zone at this area, and at contact zone between this rocks and sedimentary rock. Whereas at Tugu, Panusupan, Sambeng, North Karangsambung at litology marly clay and tuffaceous sandstone and phyllite. The landslide tipical is generally debris flow, slump and creeping. The result of this study are useful to design the mitigation strategy of landslide hazard and also may be used for land conservation requirement, particularly to develop a Master Plan of this area.

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Dec 2004, Bandung

ICHNOLOGICAL CHARACTERISTICS IN THE MODERN MAHAKAM DELTA, EAST KALIMANTAN

Ery Arifullah ¹⁾, Andang Bachtiar ²⁾ , Djuhaeni 3)

1 Master Student, Department of Geology, ITB
²GDA Consultant Jakarta
³Department of Geology, ITB

earifullah@plasa.com

Abstract

Detailed analysis of Modern Mahakam Delta sediments concentrated on identifying ichnological and sedimentological characteristics of four deltaic environments. These include: 1) distributary channel, which are typically low diversity and bioturbation index with displaying Psilonichnus, Skolithos, Ophiomorpha, Monocraterion, Teichichnus Arenicolites, Planolites, Thallasinoides, escaping traces, and Glossifungites ichnofacies; 2) estuarine tidal bar which are typically balanced diversity and biotu rbation index with displaying Psilonichnus, Ophiomorpha, Arenicolites, Skolithos, Siponichnus, Monocraterion, Paleophycus, Helminthopsis, Teichichnus, Planolites, Chondrites, Paleodictyon, crawling traces, and vertebrate track; 3) interdistributary area which are typically medium diversity and high biotu rbation index with displaying dominated Arenicolites, Ophiomorpha, Conichnus, Skolithos, Scaubcylindrichnus, Diplocraterion, Rosselia, Teichichnus, Chondrites; 4) mouth bar sediments are displaying Ophiomorpha, Planolites, grazing traces, crawling traces, fecal casting, and abundance dwelling tubes Skolithos like.

Ichnological research in the Modern Mahakam Delta potentially improves our understanding of deltaic facies sedimentology. Our findings suggest that sedimentological processes, substrate types and salinity control ichnological characteristics.

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Dec 2004, Bandung

THE GEOLOGY OF LADIA GALASKA ROAD PROVINCE NANGGROE ACEH DARUSSALAM GEOLOGI RUAS JALAN LADIA GALASKA PROPINSI NANGGROE ACEH
DARUSSALAM

Eko Seobowo, Adrin Tohari dan Hery Haryono

Pusat Penelitian Geoteknologi - LIPI
Jl. Sangkuriang, Kompleks LIPI, Bandung.40135
Tlp. 022-2503654, 2507771, Fax. 022-2504593

Abstract

In the development plan of a new and old road infrastructures, the understanding of lithology distribution aspect and fault structures are the most crucial factors on the road establishment. Geological aspects is the first thing to predict the geological hazard to prevent the negative impact on the environment, need to be evaluate.

According to the geological interpretation and field assesment along the lane of Ladia Galaska road are metamorf (sciss, phillite, quarzite) dominated and some sediment (intercalation sandstone-clay), intrusion rock (diorite) and vulcanic sediments. Presented fault structure along the road of Ladia Galaska is related to the active “Sesar Besar Sumatra” (west part) and some earth quake were occured in Blangkejeren (1997) as well. The fault structures orientation along the road are crossed and pararelled. The road lanes of Lhok Seumot – Beutong Ateuh – Ceulala and Uring – Pepela are crossed by the fault which has a local landslide problem. The road which are pararelled to the Takengon – Isaq, Ise-ise – Blangkajeren dan Pinding – Lokop fault has a tendency to the local landslide especially on the lane of the road. This research result can be use for the classification of the geological hazard and to prevent the unstable condition of the road on the future.

INDONESIAN COAL RESOURCES AND RESERVES Problems in Calculation

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Dec 2004, Bandung

INDONESIAN COAL RESOURCES AND RESERVES Problems in Calculation

F a t i m a h

Directorate of Mineral Resources Inventory

Abstract

Indonesia coal resources have been updated annually. The most recent data (2003 publication) shows that the total Indonesian coal resource is 57,847.74 million ton. This number can be classified as 12,466.42 million ton measured resources, 20,533.56 million ton indicated resources, 24,314.96 million ton inferred resources, and 532.80 million ton hypothetical resources.

Data for coal resources calculation derived from government inventory reports as well as private company reports. The main problem appears in coal resources compilation is there is no standard format in reporting Reserves and Resources of coal in their concession area. Although the government has already published the National Standard (Amendment 1 - SNI 13-5014-1998) for Coal Resources and Reserves Classification, most of private companies have not applied the standard yet. Therefore, there is no certainty for classified coal resources. Moreover, most of the coal companies (both private and BUMN) never reported the total reserve of their exploration areas. This would affect the compilation on Indonesia coal resources.

It is suggested that the government should make guidance for reporting the coal Resources and Reserves. The government also should insist coal companies to follow this guidance. Regarding resources and reserves classification, the government should strongly socialize the standard for coal resources and reserves to coal business sector (private companies, institution, as well as universities).