biostratigraphy

The Nokia 8800 Sirocco Edition Exclusive Luxcury Mobile Phone – Luxcellphone

2010-11-18T06:19:00.001-08:00

Inspired by the forces of nature and the sculptural beauty of the body, Nokia nowadays unveiled its latest premium mobile phone, the Nokia 8800 Sirocco Edition. Sensual by nature, intuitively beautiful by design, the Sirocco Edition’s signature feature is a thumbprint, which perfectly matches the human hand. The soundtrack of the Nokia Sirocco Gold Edition was composed by the avant-garde musical pioneer Brian Eno, considered the “father of ambient music.”

The Nokia 8800 Sirocco Edition draws its study from the powerful desert-born wind that originates in the abandon when a warm, dry air masses collides with the cooler, maritime air of the Mediterrean. The striking biological shape of the Nokia 8800 Sirocco Edition references the inherent strength of the human form, a concept further implied by stainless steel polished surfaces and a scratch-resistant glass display window. Like its namesake, the Nokia 8800 Sirocco Edition consists of two variants – light and dark, the light inspired by the hot, dry air mass, the dark by the cooler, humid one.

And as it blows, the powerful sirocco makes its own one-of-a-kind sound – a composition from nature caused by two air masses colliding. With nature as his inspiration, Brian Eno, the world renowned music composer and ambient music innovator, has created a one-of-a-kind ‘sonic texture’ that is organic, calm and highly evolved. It has an otherworldly feel – comprised of notes created by instruments that Eno has selected and ‘synthesized’ himself.

The stainless steel case of the Sirocco Edition is treated in such a way as to give the device a one-of-a-kind sensual feel, which humanizes this natural masterpiece. Impeccable functionality is created through superlative craftsmanship, using techniques drawn from master watchmakers and jewellers. From the sapphire coating of the 262,000 colour display to the distinctive slide mechanism which reveals its 2 mega-pixel camera, or even its extended battery life, apiece seemingly minor detail of the Nokia 8800 Sirocco Edition, unlike Nokia 8820 is honed to perfection. The ergonomic keypad undulates like the glimmering dunes of the night desert, whilst the jewel-like navigation key shines like the brightest star in the darkest night. The Nokia 8800 Sirocco Edition truly is unique, created out of the inherent beauty and chaos of nature and distilled into a contemporary form that is graceful, sympathetic and spare.

The Nokia 8800 Sirocco Edition also features a complementary Bluetooth headset. This diminutive but distinctive wireless phone is also composed of stainless steel, and perfectly matches the nature-inspired Nokia 8800 Sapphire Arte Edition.

About Nokia

Nokia is a world leader in mobile communications, driving the growth and sustainability of the broader mobility industry. Nokia connects people to apiece other and the information that things to them with easy-to-use and innovative products like mobile phones, devices and solutions for imaging, games, media and businesses. Nokia provides equipment, solutions and services for network operators and corporations.

“Structural Study of a Gold Prospect using Core Orientation Techniques - Case Study of Bundulipu Gold Prospect, Gorontalo, Indonesia”

2010-11-14T21:01:00.001-08:00

Abstract
In mineral exploration, collection of structural data is important in order to understand the
intricate interplay of structures and their impact on the mineralisation. Valuable
structural information can be gained from drill cores and it is important to extract all these
information. The best way to maximise the structural data from drill core is through core
orientation. Various methods are currently available for core orientation including:
Spear, Ezy Mark®, Ball Mark®, and Ace Core Tool®. The current study used simple
Spear-method utilising Chinagraph pencil. A procedure was developed in-house in
marking, preserving marks, drawing bottom of hole lines, and alpha and beta readings of
structures. Processing and analysis of alpha and beta readings is facilitated through
GeoCalc and GeoOrient softwares.
The core orientation procedure was applied in the definition drilling of the Bundulipu
Gold prospect in Avocet’s Totopo Project, Gorontalo, Indonesia. Combined with logging
of vein mineralogy, vein textures and cross-cutting relationships, Avocet geologists were
able to come-up with a feasible interpretation of the structural paragenesis and its impact
on the gold mineralisation.
The Bundulipu prospect is characterised by epithermal quartz-sulphide veins hosted by
Pliocene dacitic to rhyolithic pyroclastic rocks. It was originally interpreted that these
veins were developed within a pair of NW-SE trending sinistral faults forming a small
pull-apart basin. Mineralised quartz-sulphide veins form within this pull-apart basin.
Structural measurements in drill cores showed that mineralised veins occur as moderate
to steep, northwest dipping veins trending ENE-WSW to NE-SW. Unmineralised veins,
on the other hand, have gentle to moderate dips to the north-northeast and west. The
structural readings of these veins and their spatial distribution confirmed the regional
structural interpretation of a dominant E-W stress field and the development of veins in a
small pull-apart basin. Vein paragenesis and fault readings indicate that this stress field
has a protracted history that outlived the mineralisation event. This interpretation helped
significantly in the delineation of the vein system at Bundulipu.

By: Eddy Da Costa/ Boyet Bautista
PT. Avocet Bolaang Mongondow
Jl. Kol Sugiono no 24 – Kotabangon
Kotamubagu – Sulawesi Utara
Phone : 0434 – 2628776
Fax : 0434 – 22965

Fluvial-Dominated Deltas

2010-11-14T15:18:00.001-08:00

Fluvial-Dominated Deltas
Fluvially-dominated deltas are primarily controlled by the water density difference between the inflowing river water and the standing water on the basin.
Different flow types that determine the distribution of sedimentand sedimentary structures formed in the delta are homopycnalflow, hyperpycnalflow, and hypopycnalflow
Homopycnalflowoccurs when the density of the river water is equal to the density of the standing water in the basin..
Hyperpycnalflowis produced when the density of the river water entering the basin is greater than the density of the standing water in the ocean basin. This higher density river water will flow below the standing water in the basin because ofthe difference in density.
Hypopycnalflowis associated with a lower river water density entering a higher density standing water in the basin. Under these conditions, the river water will flow out over the standing water, gradually depositing the suspended clay portion of the sediment load on the prodelta.

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2010-11-11T14:19:00.001-08:00

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Marshes and mangrove swamps

2009-12-10T02:25:00.000-08:00

This article from foraminifera site

Marshes and mangrove swamps

Tidal marshes and mangrove swamps represent transitional regions between marine/brackish water and terrestrial environments. Tidl marshes occur in temperate areas, whereas the mangrove swamp is characteristic for tropics

Murray (1972) lists the following characteristics of these environments :

It is developed in the upper part of the intertidal zone
During much of each tidal cycle it is exposed to the atmosphere
It spends a smaller part of the tidal cycle submerged beneath sea or estuarine water
It is subject to the more dramatic fluctuations in temperature of the atmosphere
Fresh water is periodically introduced from rain showers
There is usually high organic productivity by the marsh plants and microflora
The fauna comprises few permanent indigenous species although migratory terrestrial animals are sometimes common

Tidal marshes can be subdivided in three groups according to salinity;

Hyposalina marshes
Normal marine marshes
Hypersaline marshes

Species diversity is highest in hyposaline marshes, although the general diversity is low.

The hyposaline marshes are characterized by the predominance of arenaceous species (Miliammina sp., Ammotium sp., Trochammina inflate) and rotaliids ( Elphidium spp.) and the absence of miliolids

Normal marine marshes are inhabited by dominantly arenaceous species with minor miliolieds and rotaliids.

In hypersaline marshes the percentage of arenaceous species, miliolids and rotaliids is about equal.

Typical cosmopolitan marsh species are:

- Ammotium salsum

- Arenoparrella Mexicana

- Miliammina fusca

- Taclammina macrescens

Interpreting an ancient marsh environment may be difficult. Due to reducing conditions calcareous test are easily destroyed after death. After complete solution of calcareous species, it is impossible to distinguish between the various marsh environments. Only the low diversity and an assemblage consisting of small arenaceous species such as Trochammina sp.. Haplophragmoides sp., Ammobaculites sp. points to a marsh origin. If Miliammina sp is present in this assemblage, a hyposaline lagoon could also be indicated.

Introduction Tectonics

2009-02-03T23:47:00.001-08:00

Tectonics

From Wikipedia, the free encyclopedia

Tectonics, (from the Greek for "builder", tekton), is a field of study within geology concerned generally with the structures within the crust of the Earth (or other planets) and particularly with the forces and movements that have operated in a region to create these structures.

Tectonics is concerned with the orogenies and tectonic development of cratons and tectonic terranes as well as the earthquake and volcanic belts which directly affect much of the global population. Tectonic studies are also important for understanding erosion patterns in geomorphology and as guides for the economic geologist searching for petroleum and metallic ores.

A subfield of tectonics that deals with tectonic phenomena in the geologically recent period is called neotectonics

Tectonic studies have application to lunar and planetary studies, whether or not those bodies have active tectonic plate systems.

Since the 1960s, plate tectonics has become by far the dominant theory to explain the origin and forces responsible for the tectonic features of the continents and ocean basins.

There are three main types of tectonic regime

Extensional tectonics
Thrust (Contractional) tectonics
Strike-slip tectonics

Extensional tectonics is concerned with the structures formed, and the tectonic processes associated with, the stretching of the crust or lithosphere.

Areas of extensional tectonics are typically associated with:

The development of continental rifts, with or without the effects of mantle upwelling
The gravitational spreading of zones of thickened crust formed during continent-continent collision
Tensional flexures along strike-slip faults
On passive margins where an effective basal detachment layer is present at the upper end of a linked system

Extensional structures

The main structures formed in areas of extensional tectonics are normal faults and graben structures.

Prominent examples include:

The East African Rift, a major continental rift system
The Basin and Range province of western North America
The global mid-ocean ridge system
The Dead Sea basin formed at a releasing bend along a continental transform boundary

Thrust tectonics is concerned with the structures formed, and the tectonic processes associated with, the shortening of the crust or lithosphere.

Areas of thrust tectonics are typically associated with:

The collision of two continents or a continent and an island arc at a destructive plate boundary
Restraining bends on strike-slip faults
On passive margins, balancing up-dip extension, where an effective detachment layer is present

Strike-slip tectonics is concerned with the structures formed by, and the tectonic processes associated with, zones of lateral displacement within the crust or lithosphere.

Areas of strike-slip tectonics are associated with

Continental transform (conservative) plate boundaries
Lateral ramps in areas of extensional or contractional tectonics accommodating lateral offsets between major extensional or thrust faults
Zones of oblique continent-continent collision
The deforming foreland of a zone of continent-continent collision, a process sometimes known as escape tectonics

Introduction geology

2009-02-03T19:12:00.001-08:00

From Wikipedia, the free encyclopedia

Geology (from Greek: γη, gê, "earth"; and λόγος, logos, "speech" lit. to talk about the earth) is the science and study of the solid matter that constitutes the Earth. Encompassing such things as rocks, soil, and gemstones, geology studies the composition, structure, physical properties, history, and the processes that shape Earth's components. It is one of the Earth sciences. Geologists have established the age of the Earth at about 4.6 billion (4.6x10⁹) years, and have determined that the Earth's lithosphere, which includes the crust, is fragmented into tectonic plates that move over a rheic upper mantle (asthenosphere) via processes that are collectively referred to as plate tectonics. Geologists help locate and manage the Earth's natural resources, such as petroleum and coal, as well as metals such as iron, copper, and uranium. Additional economic interests include gemstones and many minerals such as asbestos, perlite, mica, phosphates, zeolites, clay, pumice, quartz, and silica, as well as elements such as sulfur, chlorine, and helium. Geology is also of great importance in the applied fields of civil engineering, soil mechanics, hydrology, environmental engineering and geohazards.

Planetary geology (sometimes known as Astrogeology) refers to the application of geologic principles to other bodies of the solar system. Specialised terms such as selenology (studies of the moon), areology (of Mars), etc., are also in use. Colloquially, geology is most often used with another noun when indicating extra-Earth bodies (e.g. "the geology of Mars").

The word "geology" was first used by Jean-André Deluc in the year 1778 and introduced as a fixed term by Horace-Bénédict de Saussure in the year 1779. The science was not included in Encyclopædia Britannica's third edition completed in 1797, but had a lengthy entry in the fourth edition completed by 1809.An older meaning of the word was first used by Richard de Bury to distinguish between earthly and theological jurisprudence.

About larger foraminifera

2008-10-22T20:55:00.001-07:00

Larger foraminifera is the term applied to those benthonic foraminifera which in general are relatively large and of which only the internal structure can be used for determination. Thus tests must be sectioned.

The rapid evolution of most taxa makes larger foraminifera a valuable group for relative age determination. However, for a variety of reasons they probably are the most difficult to use for biostratigraphy :

All larger foraminifera have a very limited facies range, and thus first appearance and last appearance more often reflect facies changes than real first appearance and extinction levels.
All foraminiferal taxa have a certain variability. Being rather complicated the larger foraminifera have many characters in which they can vary. This has lead to unwarranted splitting into numerous species most of which can not be recognized and have no stratigraphic value.
Existence of homeomorph. There are several independent evolutionary series which lead to virtually identical forms. These may be identical developments at different times (e.g. the evolution from Heterostegina to Spiroclypeus happened at least twice, once in the Upper Oligocene and once in the Upper Eocene) or similar developments from deferent ancestors leading to similar forms (e.g. Lepidocyclina/Lepidorbitoides).

Larger foraminifera are mostly found in carbonate deposits and often cannot be separated from the rock. They are therefore studied in thin section which permits identification to genus level only. Section rich in larger foraminifera are dated using the Indo-Pacific Letter Stage System of Classification.

This system was introduced as a simple but effective way of dividing up the tertiary.

The Indonesian Letter Stages were originally proposed by Van der Vlerk and Umbgrove (1927) to replace the European Tertiary Stages, which could not be applied in Indonesia. However, although, this zonation originated in Indonesia, Adams (1970) makes it clear that the zonation is an applicable to much larger area.

Many authors refer to the units of the letter classification as stages and use the letter units as chronostratigraphic units. However, the concept involved is wholly biostratigraphical. According to Article 46 of the Stratigraphic Code of Indonesia, the Letter Stages Classification is "a geochronologic concepts, essentially derived from biostratigraphic classification based upon a number of concurrent range zones of larger foraminifera". However, the letter stages are really only very broad stratigraphic units. Larger foraminifera are useful in correlation of shallow water marine carbonate sediments of Eocene - Late Miocene Age. The Letter Stage originally consisted of eight major units, designated "Tertiary a" to "Tertiary h". These are usually written Ta, Tb etc. Ta is the oldest division, Th the youngest. Some of these units are further subdivided into numbered divisions e.g. Tf1, Tf2, Tf3.

About foraminifera

2008-10-22T20:54:00.001-07:00

Planktonic foraminifera are everywhere used as a tool for biostratigraphic purposes, but in some cases due to the unfavourable conditions they are not always present. Moreover these planktonic foraminifera are not always well preserved, oftenly indeterminable and undiagnostic. Thus another biostratigraphic tool is wise to be exposed.

Many investigations indicated that the benthonic foraminifera very useful in dating the sediment locally, beside the major use in the recognition of paleoenvironments. The ability to accurately determine environment is of fundamental importance in the oil industry since both hydrocarbon source rocks and reservoir rocks accumulate under rather restricted environmental condition.

Bandung Basin

2008-05-23T02:17:00.000-07:00

Abstract
Environmental problems occurring in the Bandung Basin are resulted from improper management pertaining to land and spatial planning, including landuse policy and control. Arising environmental problems are covering disturbance of watershed hydrological function, surface and groundwater quality and quantity, solid waste, and air quality. Environmental studies in the Bandung Basin have been implemented by landuse change interpretation, surface water regime measurements, water quality, solid waste management, and air quality. Landuse change has occurred where some vegetation areas, such as forests and paddy fields, have decreased for 54% in one hand, and developed area has increased into 223% in the other hand. Watershed degradation is indicated by run off coefficient increasing from 0.3 in 1950 to 0.55 in 1998. Flow regime has also changed by presence of a maximum extreme discharge increasing tendency from 217.9 m3/sec in 1951 to 285.8 m3/sec in 1998, and minimum extreme discharge decreasing tendency from 6.35 m3/sec in 1951 to 5.7 m3/sec in 1998. Groundwater productivity index continued decreasing from 0.1 million m3/unit in 1900 to 0.0188 million m3/unit in 2002. Environmental problem has also occurred in a solid waste management sector where an average level of service is only 43.7%, and air pollution by motor vehicle and industrial emission, such as PM10, NOx, CO2, SO2, Pb, and acid rain phenomena have also occurred. Fresh water supply level of service in the Bandung Basin only covers 43% of the total needs. Watershed degradation occurring in the Basin needs a management system recovery, administrative based-management that shifted to ecological based integrated watershed management.
Effort and strategy required include the policy and institutional reassembling, pollution control, land rehabilitation and conservation, and community empowerment.Keywords: land use, watershed, run off coefficient, environmental strategy

Hidrotermal Taran Area

2008-05-23T02:16:00.000-07:00

Abstract
Taran area is occupied predominantly by piroclastic rocks and locally intercalations of lenticular claystones and sandstones. The pyroclastic rocks are intruded by diorite, dacite and andesite, leading alteration and mineralization within the host rocks. Mineralization occurs as a vein type and is associated with a number of pervasive alteration types named respectively: quartz-illite-montmorillonite-kaolinite ± pyrite, quartz-illite ± pyrite, quartz-illite-chlorite ± pyrite and quartz-kaolinite-illite ± pyrite. On the other hand, a propylitic alteration also occurs within the andesite intrusion composed of calcite-epidote-chlorite-sericite-quartz ± pyrite. The mineralization is characterized by several zones of quartz stockwork containing gold and associated ore minerals of chalcopyrite, sphalerite, galena, pyrite and argentite. The quartz veins occurs as fillings of structural openings in the form of milky quartz and amethyst with textures of sugary, comb, and dogteeth.
Evaluation work on results of microscopic (petrography and mineragraphy), X-Ray Diffraction (XRD), and fluid inclusion studies, and chemical analysis of entirely altered rock/quartz vein samples shows that the alteration and mineralization process were closely related to a change of hydrothermal fluids, from near neutral into acid conditions at a temperature range of >290o – 100oC. The appearances of quartz variation indicate a relationship with repeated episodes of boiling in an epithermal system, as ground water mixed with hot vapor originated from a remained post-magmatic solution. Corresponding to a salinity of average 1,388 equiv.wt.% NaCl, it indicates that the ore minerals bearing quartz veins were deposited at a depth range of 640 – 1020 m beneath paleosurface.
Keywords: Hydrothermal alteration, gold mineralization, epithermal

Anak Krakatau Volcano

2008-05-23T02:15:00.000-07:00

Abstract
Since its appearance in 1929, Anak Krakatau Volcano has been growing fastly. The elevation of Anak Krakatau Volcano from 1930 to 2005, within 75 years, has reached 315 m high. The growth rate is approximated to be four meters per year in average. Based on calculation, the volume of the body from the sea floor since 1927 until 1981 was 2.35 km3, and then in 1983 was 2.87 km3 and then in 1990 it reached 3.25 km3. The latest volume measurement in 2000, was 5.52 km3. Between 1992 up to 2001, within nine years, the eruption of Anak Krakatau took place almost every day, and it had caused its elevation to increase more than 100 m, and its area extent to become 378,527 m2. If the increase in height and the increase in volume are consistent, it is expected that in 2020, the volume of Anak Krakatau’s edifice will proceed the volume of Rakata Volcano, Danan Volcano, and Perbuwatan Volcano (11.01 km3) shortly before catastrophic eruption in 1883. Since this volcano appeared above the sea level, the succession of vegetation never came up to a climax, except some of the species, such as Saccharum sp. and Casuarina sp. those are growing faster after the eruption stopped. The growth of coral reef on the lava flows that entered the sea about ten years ago, was much slower than those which are growing around the Rakata, Panjang and Sertung Islands. This case is probably due to the slow rate of cooling process of the lava flows, although the lava surfaces are blocky.

Keywords: growth of volcano, succession of vegetation

volcanic merapi

2008-05-23T02:13:00.000-07:00

Abstract
The Merapi Volcanic debris flow, which is familiarly known as lahar, is formed from pyroclastic deposits that is slided by high rain water. Now, the pyroclastic deposits are produced from a collapsing lava dome. The suspension flows downhill in a high speed, to produce a turbulent flow. That flow are usually developed within areas of a different morphology having high to lower slope gradient, known as a slope fold of a foot hill. The study is based on the measurement and identification of large fragments of the surface deposits. Analysis includes imbrication direction, grain shape, and grain size of the fragments. The result of the study shows the model of a flow direction of large fragments of upper part of debris that form “frog back model” or “elephant back model”. The head of the frog or elephant explains the flow direction. The result of the research confirms that the model is valid for fragments having a range size of diameter of 90 cm or larger. In the studied area, the fragment of 90 cm in diameter has reached a distance up to 22 km from the source. Therefore the result of this research is able to be used as a model in determining the paleo-debris flows of unknown source.
Keywords: lahar, fragment, imbrication, model, flow

Geology of Jakarta Basin

2008-05-23T01:38:00.000-07:00

Abstract
Geologically the Batuceper and Benda Sub-Regencies belongs to the western part of the Jakarta Basin. The area is covered by coastal alluvial and delta deposits, and volcanic product. Understanding the distribution and groundwater pattern, either in the shallow part or the deep part, are of the basic thing for a geometric model and its groundwater flow in identifying the groundwater conservation.
The result of the aquifer distribution, either in the shallow or the depth parts, was approached by the geoelectrical and hydrogeological surveys in the field and well data that has resulted in aquifer distribution, either in the shallow or the deep parts. In general, the shallow aquifer developed downward becomes semi confined and confined aquifers. Groundwater flow pattern indicated local cones depression of groundwater level, especially around the city. Depression of groundwater level is considered to be related to the natural shape of aquifer as lences. However, it was possible to be caused by over pumping in this zone.
Keywords: Jakarta Basin, groundwater, flow pattern, aquifer, groundwater conservation

PROCEDURE IN PALEONTOLOGICAL EXAMINATION OF SUBSURFACE SECTIONS

2008-05-14T21:33:00.000-07:00

PROCEDURE IN PALEONTOLOGICAL EXAMINATION OF SUBSURFACE SECTIONS

Depositional environments of subsurface geologic sections of interest are interpreted primarily from occurrence of species and assemblages of foraminifera. Criteria for interpretation begin with studies of Recent foraminifera obtained from plankton tows and bottom samples collected from sea floor traverses and supplemented by similar studies in the other areas. This method permits correlation of species to environment of deposition, and information on water depths, salinities, temperatures and other significant factors may be obtained. Many Recent foraminifera are either closely related or identical to Tertiary forms; thus, knowledge of depositional environment of modern species may be used to reconstruct ancient environments from occurrences of fossil foraminiferal species. However, associated stratigraphic factors, such as lithology, indicate that some fossil species in the geologic section occurred at shallower water depths than to their modern counterparts in the Recent. This emphasizes the fact that all available stratifgraphic information must be used in making paleoecologic interpretation. By this method, information has been accumulated to show that each environment, from the up-dip transitional to the abyssal zone of the ocean deeps, has characteristic species and assemblages of foraminifera. Only few genera and species are actually restricted to one environment. However, the over-all association or assemblage, together with relative abundance or scarcity of significant genera and species, will usually permit sufficiently accurate interpretation of the representative environment. For paleontological purposes, the species with the greatest tolerance for many different environments and uniform extinction makes the best “time correlation” marker fossil, but it obviously a poor paleontologic indicator. Despite these reservations, in Gulf Coast paleontology studies, collections of Recent species in Gulf Mexico are closely related to fossil species and of most use. As pointed out by Tipsward et al., (1966), excerpted from Crouch (1955), world-wide species distribution data are not applicable to all local stratigraphic problems, and widely scattered ecology data may be confusing.
Paleoecological studies of well sections are usually made simultaneously with paleontological determinations. For paleontological purpose, species of foraminifera and their relative abundance in each sample of drill cuttings are recorded, along with lithologic description and notation of other fossil. After the complete set of samples has been examined from the top to bottom, the detailed record of fossil occurrences and lithology is reviewed and a paleoecological summary is prepared. This summary gives the depositional environment represented according to depth, the approximate location with respect to the ancient shoreline, the cyclic nature of the section (transgressive or regressive), a brief lithologic description, and the geologic age.
The paleoecology may then be plotted on electriclogs and incorporated in cross section and maps to assist exploration as previously described (Tipsward et al., 1966).

ECOLOGY OF RECENT ORAMINIFERA

2008-05-14T21:32:00.000-07:00

ECOLOGY OF RECENT ORAMINIFERA

The distribution of foraminiferal taxa is influenced by many different factors. Although many authors consider water depth the most significant one, water depth specifically is not the main variable, the controlling factor being the various physical and chemical conditions associated with depth. Typical factors are temperature and temperature variability, light availability, sedimentation rate, bottom characters, energy conditions and pressure.
Studies of recent foraminiferal ecology have provided numerous distinct criteria by which many depositional environments can be characterized and which can be applied to fossil assemblages from sedimentary rocks. Some the main variables can be summarized as follows:
1. The total number of species and of individual increases away from the shoreline, and with increasing depth of water, to maximum values on the outer shelf and in the upper bathyal zone.
2. Porcellaneous forms show their present diversity in shallow, nearshore environment.
3. Arenaceous foraminifera with simple interior wall structure become dominant in shallow waters or in intertidal areas. The percentage occurrence of these arenaceous forms reaches a maximum near the effluence of rivers.
4. Calcareous foraminiferal tests become smaller and thinner near sources of fresh water. In carbonate rich environments, tests may reach a large size and be very robust
5. The percentage occurrence of the most common species in a foraminiferal population relates to the variability of the environment. As marginal marine conditions are approached, environmental parameters become more pronounced resulting in a tendency towards single species dominance in the most unfavorable environment.
6. Planktonic forms occur most abundantly within the outer neritic and deeper waters. Under ideal sedimentation conditions, especially in clastic deposits, planktonic foraminifera can show a more or less regular increase in abundance in depth.
7. Arenaceous taxa with labyrinthic wall structures occur most abundantly in bathyal or deeper waters. In sediments deposited below the calcium carbonate compensation depth (CCD) these forms may become dominant since the calcareous shells of other foraminifera are dissolved.

APPLICATION TO ANCIENT ENVIRONMENTS

2008-05-14T21:28:00.000-07:00

APPLICATION TO ANCIENT ENVIRONMENTS

The study of paleoenvironments is based on the concept of uniformitarianism i.e. “The present is the key to the past”.
Care must be taken. Within young Tertiary rocks there is very close correspondence between fossil and recent foraminiferal assemblages. But in older sediments, of Early Tertiary to Mesozoic age, gross differences may occur as in these periods certain groups of foraminifera common in modern environments had not appeared and other group existed which have no modern counterparts. Examples are the rotaliids, which are essentially a tertiary development, and Cretaceous Globotruncana which are thought to have had similar, but not identical, requirements to modern planktonics. The ecology of extinct groups can be determined by carefull study of sedimentology and analysis of large numbers of fossil assemblages.
Additional complications may be added since many foraminifeal tests may be transported vast distances before actually becoming incorporated into a sediment, thus two assemblages : biocoenosis (living assemblage) and thanatocoenosis (dead assemblage). For example of transportation which may result in mixtures of faunas are as follows :
1. Reworking of foraminifera into younger
rocks.
2. Contemporaneous transport :
· as suspended load; the empty shells of dead foraminifera can be transported hundreds of kilometers offshore, resulting in the presence shallow water forms in deep water deposits.
· by currents; this may be reflected by the presence of size sorted or species sorted assemblages.
· by turbidity currents or slides; resulting again in the presence of shallow water forms in deep water environments.
· wind; empty shells of dead foraminifera may blown land wards.
Diagenesis may also seriously effect to fossil assemblages; solution of the calcareous tests or calcareous cement of arenaceous forms may result in the complete absence of a fossil fauna.
When material from well sections is studied and cuttings are examined, contamination may occur from higher in a well section in the form of caving. Caving may be recognized by differences in preservation, color of the degree of abrasion of foraminifera. Often, however, it may not be at all clear whether foraminifera are in situ, or caved. Analysis of carefully selected core material or sidewall cores from a sequence in question would provide an indication of the true in situ assemblage.

benthic marine environment

2008-05-14T21:27:00.000-07:00

The benthic marine environment compiled from Hedgpeth (1957) and INGLE (1980) :

Non-marine (supralittoral) – top delta, alluvial plain etc.
Lorenz (1863) proposed supra-littoral for the term above extreme high water (Hedgepeth, 1957). This zone include top delta, alluvial plain etc.

Transitional zone (littoral) - brackish water, bay, marsh, lagoon, estuaries, deltas, beaches, tidal flats.
The term littoral has been used to mean the region between high-tide and low-tide level (Forbes and Hanley, 1853). Brakish water, bay, marsh, lagoon, estuaries, deltas (except top delta) are grouped into the transitional zone.

Neritic zone (0 to 100 m)
The region between the low-water line and the edge of the continental shelf, or betweeen shore and extends downwards to about 20 to 50 fathoms (about 36.54 – 91.35 m) is continental shelf. The term for the aquatic environment overlaying this region, the water over the continental shelves, is “neritic”, proposed by Haeckel to complement “oceanic”, the environment of the “blue water”. But paleontologist, working with the remains of the benthic organism of shallow seas, have applied the term “neritic” to the environment of the bottom itself (Hedgpeth, 1957).

Inner neritic - shallowest open marine (inner shelf or shallow inner sub-littoral) environment between 0 to 20m (approx. 0 to 66 feet)
Effective fair weather wave base at about 10m to 15m (Figure 3 of Ingle, 1980).
The lower boundary of this depth zone is roughly equivalent to the maximum effective weather wave base.

Middle neritic - intermediate open marine (middle shelf or deep inner sublittoral) environment - 20 to 100m (approx. 66 to 328 feet).
The region between water and the maximum depth of large attached algae or of reef-coral growth is called as middle neritic (Hedgepeth, 1957). Everage lower boundary of photic zone at tropic marine at about 100m to -120m depth.
The lower boundary of this depth zone is roughly equivalent to the lower boundary of photic zone at tropic marine, or to the maximum depth of large attached algae or of reef-coral growth.
Everage lower boundary of reefal ecologic is 50m. There are the moderate to abundant large foraminiferes associate to the reef. Bellow of this depth, they are very rare (Ingle, 1980). So that, we divided the middle neritic zone into two zones, shallow middle neritic (20m-50m) and deep middle neritic (50m-100m).

Outer neritic zone - deeper open marine (outer shelf or outer sublittoral) environment - 100 to 200m (approx. 328 to 656 feet).
Average maximum depth of continental shelf is 200m depth (Ingle, 1980). The term outer shelf (outer neritic or outer sublittoral) applied to the region between the maximum depth of large attached algae or of reef-coral growth to the average maximum depth of continental shelf.

Upper bathyal zone, -200 to -500m (approx. 656 to 1640 feet).
Bathyal have frequently been applied to the environment of the continental slope down to 2000m, but its usage has not gone much beyond the diagrams in the textbooks.

Middle bathyal zone, -500 to -2000m

Upper middle bathyal zone (500-1500m)
The upper middle bathyal zone is effectively coincides with the oxygen minimum zone (500 to 1500m) (Ingle, 1980), a parcel of water containing only marginal amounts of dissolved oxygen (0.1-0.5 ml/l) due to the oxidation of the organic debris derived from high productivity in the overlying photic zone (Richad, 1957 in Ingle ,1980).

Lower middle bathyal zone (1500-2000m)
Continental slope and bathyal have been applied to the environment of the continental slope down to maximum 2000m (Hedgpath, 1957).

Lower bathyal zone, -2000m to -4000
Bellow 2000m (roughly between 2000m and 3000m, and extends downward to about 6000 m) the temperature is never above 4oC, (Hedgpeth, 1957). The base of lower bathyal zone is delimited by the top of the CCD in mid-latitude oceanic areas today (Ingle,1980)

Abyssal zone, -4000m to 6000m.
Critical deeper boundaries include the lysohaline (LCD) and the calcium carbonate compensation depth (CCD) at 3000 to 4000m (Berger, 1970, 1974); top of the abbysal zone (4000m) is essentially coincide with the top of the CCD in mid-latitude oceanic areas today (Ingle, 1980). Below 4000m, the living and presence of foraminifera was under the influence of CCD. The calcareous foraminiferal tests are dissolved (Berggren, in Haq and Boersma, 1980; Ingle, 1980).
The temperature of the water body at roughly between 2000 and 3000meters and extends downward to about 6000 meters is never above 4oC (Hedgpeth, 1980).

Hadal zone, more than –6000m.
The distinct characteristic of the fauna of the deep trenches suggest that Hedgpeth is dealing with another environment region, for which Bruun has proposed the term “hadal” (from Hades). The term for the region bellow 6000m depth.

2008-05-13T19:00:00.000-07:00

GONDWANAN PALYNOMORPHS FROM THE PALEOGENE SEDIMENTS
OF EAST JAVA: ?THE EVIDENCE OF EARLIER ARRIVAL

BY EKO BUDI LELONO*)

*) R&D Center for Oil and Gas Technology “LEMIGAS”, Jakarta

ABSTRACT
The palynological investigation of the Paleogene sediments is based on cutting samples collected from the exploration wells which are drilled in East Java area. The occurrence of pollen Meyeripollis naharkotensis and spore Cicatricosisporites dorogensis in the upper well sections suggests the pollen zone of Meyeripollis naharkotensis which is equivalent to Oligocene age. Meanwhile, the occurrence of pollen Proxapertites operculatus and spore Cicatricosisporites eocenicus below Meyeripollis naharkotensis zone indicates the appearance of Proxapertites operculatus zone within the lower sections which is equivalent to Eocene. In addition, foraminiferal and nannoplankton analyses confirm the Oligocene-Eocene age by identifying the occurrence of letter stage of Te4-Tb and nanno zone of NP20-NP25. The appearance of the Gondwanan/ Australian elements including Dacrydium and Casuarina with common and regular occurrences throughout the studied sections are controversial as these pollen are recorded in the younger sediments (Early Miocene) of other areas such Java sea, South Sumatra and Natuna sea following the collision of the Australian plate and the Sundaland in the latest Oligocene. Further more, the absence of these palynomorphs within the Paleogene sediments of Central Java and South Sulawesi strengthens the above assumption. Therefore, in regard to East Java, the appearance of Dacrydium and Casuarina may indicate earlier arrival of the Gondwanan/ Australian fragment in this area compared to that in other areas of Indonesia.