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.

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

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

TUNGSTEN AND GOLD MINERALIZATION IN THE LATUPA AREA, LUWU DISTRICT, SOUTH SULAWESI

Bambang Nugroho Widi* ), Sudarsono**)

*) Direktorat Inventarisasi Sumber Daya Mineral, Bandung
**)Puslitabang Geo-Teknologi LIPI, Bandung

Abstract

Tungsten mineralization occurrences in the Suguntu area, Latupa form an unique mineralization to study, particularly in the Indonesia Archipelago geological setting. It is usually occurred commonly in the continental or cratonic environment granitic rock. The presence of gold and a number of other sulfide- oxide minerals such as arsenopyrite, chalcopyrite and mangan as mineral association make the mineralization become more interesting and important in this region. Mineralization in this area is indicated by the presence of tungsten mineral (wolframite) bearing quartz vein intruding the granitic and metasediment host rocks. The vein trend is generally of about N 170 ° E to 190° with dip of about 70° to 90° with thickness from few centimeters to nearly 20 centimeters. Altered rocks type present in this area involve argil itization, propyl itization, seritization (phyll ic). Silicification found locally, particularly near to the vein. Based on the physical appearrence on the specimens, minerals association recognized are cahalcopyrite, pyrite, magnetite, hematiti and mangan. It seem mineralization formed in the mesothermal environment, at depth lower than epithermal zone (more than 500 meters below the paleosurface) with temperature formation > 300°. However, in order to ensure this suggestion, study on geochemistry, ore microscopy, fluid inclusion, petrography, pima, etc, are hughly needed to obtain an imagination clearly in connection to know the relationship between tungsten (wolfram) and gold mineralization.

MINERAL RESOURCE ASSESSMENT OF PORPHYRY COPPER DEPOSITS IN INDONESIA USING THE USGS 3-PART ASSESSMENT

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

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

MINERAL RESOURCE ASSESSMENT OF PORPHYRY COPPER DEPOSITS IN INDONESIA USING THE USGS 3-PART ASSESSMENT

METHOD

Bambang Tjahjono Setiabudi

Directorate of Mineral Resources Inventory
E-mail: BTSetiabudi@hotmail.com

ABSTRACT

Mineral Resource Assessment is a field of research and application of quantitative appraisal methods to evaluate potential mineral resources. Principally it describes mineral deposits, measures their grade and tonnage, estimate the occurrence of the undiscovered deposits and estimates mineral resources in the permissive tracts. The main objectives are to outline the principal areas in Indonesia that have potential for selected undiscovered mineral resources and to estimate the probable amounts of those mineral resources to a depth of 1 km below the earth's surface. The assessment is carried out using the USGS 3-Part Quantitative Mineral Resource Assessment Method. The 3-part method consists of firstly, delineating tracts for commodities and porphyry Cu deposit types based on the geology of the ore deposits, secondly, estimating the amount of resources contained in the undiscovered deposits using appropriate ore characteristics and metal contents based on grade and tonnage models and thirdly, estimating number of undiscovered deposits of each type for each delineated area. Overview of porphyry copper resources in Indonesia as the results of mineral assessment includes standardized database for known mineral deposits and occurrences, digital regional-scale maps of tracts permissive for current known deposits as well as undiscovered mineral resources, and estimates of undiscovered mineral resources within permissive tracts for copper (copper-gold).

ORGANIC PETROLOGY OF SELECTED TERTIARY KALIMANTAN COALS

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

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

ORGANIC PETROLOGY OF SELECTED TERTIARY
KALIMANTAN COALS

By :

Binarko Santoso and Bukin Daulay

R and D Centre for Mineral and Coal Technology
Jalan Jenderal Sudirman 623 Bandung 40211
Ph. 022-6030483, fax. 022-6003373, email binarkos@tekmira.esdm.go.id

ABSTRACT

Study on organic petrology was carried out on both East and South Kalimantan Palaeogene and Neogene coals. West and Central Kalimantan coals are ignored in the study, because their geological conditions are not favourable and the seams are usually thin and generally rich in argillaceous or arenaceous mineral matter.

Similarities and differences in type and rank characteristics in the coals reflect their geological setting. Rank and type variation of the coals were assessed by petrographic examination of 40 samples. The coals are dominated by vitrinite, common exinite and rare inertinite and mineral matter. The type differences reflect climatic influence and differences in peat conditions.

Rank of the coals depends largely on the geological age and the level of temperature under confining pressure (burial depth). Increased depth of burial and increased temperature and pressure over a period of time, consequently result in higher rank. Reflectance measurements on the coals indicate that there is a substantial difference in rank between Palaeogene and Neogene coals. The Palaeogene coals are sub-bituminous to high volatile bituminous rank (R_vmax of 0.53- 0.67%), whereas Neogene coals are brown to sub-bituminous rank (R_vmax of 0.30-0.57%), according to the Australian classification.

FROM NON-ECONOMIC INTO PRODUCING FIELD, A CASE STUDY IN KETALING BARAT FIELD, INDONESIA

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

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

FROM NON-ECONOMIC INTO PRODUCING FIELD, A CASE STUDY IN KETALING BARAT FIELD, INDONESIA

Bob W.H. Adibrata⁽¹⁾, Y. Hirosiadi⁽²⁾, E. Septama⁽³⁾, A. Rachmanto⁽⁴⁾

¹bobwikan@pertamina.com, ²yosihiro@pertamina. com, Geology Section, Technology Support Division,
Pertamina Upstream, Kwarnas Bld 15^th Fl, Jl. Medan Merdeka Timur No. 6, Jakarta 10110 INDONESIA
³erlangga@pertamina-sumbagteng.com, Exploitation Section, Pertamina DOH Sumbagteng, Bajubang, Jambi
36611, INDONESIA
⁴ambar@pertamina-dohsbs. com, Recent address: Exploitation Section, Pertamina DOH Sumbagsel, Prabumulih,
Sumatera Selatan, INDONESIA

Abstract

Focus of this study is re-activity of a non-economic field into production by combining old vintage 2D seismic data with current 3D seismic data, supporting with archival, conventional log data and limited sidewall core and thin section analysis. The reservoir consists of bioclastic wackestone overlying by coral bindstone in the Upper Miocene Equivalent of Baturaja Formation, at Ketaling Barat field, Jambi, Indonesia. The objective of this study is to evaluate and test a multiple attribute analysis whereby carbonate facies can be determined and to characterize the distribution of potential carbonate reservoir.