bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical appraisal of the Whittle 3-D open-pit mine optimization software package
Authors: Costelloe D. J. 
Published: April 2008

Abstract
In 1965 Lerch & Grossman produced a paper describing a 3-D algorithm based on graph theory which could be specifically applied to the optimization of open-pit mine designs. At the time, most computers were incapable of performing the large quantities of iterative calculations required by the method. A 2-D algorithm was also described which, though effective on sections, lost its optimized quality when sections were combined. The 3-D algorithm therefore remained the preferred option.
In 1986 the Whittle 3-D open-pit optimization package was launched by Whittle Programming Ltd. This package utilized the Lerch-Grossman algorithm for the first time in a commercial software application. Since then the package has undergone a number of changes and improvements.
The purpose of an optimization package is to produce the most cost effective and most profitable open-pit design from a block model of an orebody. It must be capable of rapidly analysing alternatives accurately; it must be able to carry out sensitivity analyses of different components to assess financial risk; it must allow frequent updates to take into account changes in costs etc. and it must allow the production of interim designs. In today’s mining world, a hastily produced or non-rigorous design is financially unacceptable as the design determines the potential for profit or loss. To develop this further it is essential not just to make a profit but to maximize the return on investment.
This paper appraises the ability of the Whittle 3-D package to satisfy this objective.
Grade control for Australian open pit gold mines
Authors: Davis J. G. 
Published: April 2008

Abstract
The deposits exploited in Australian open pit gold mines are often small and of low grade with highly variable gold distributions. Consequently, they require detailed grade control. The nature of these grade control programmes is outlined together with a description of the various computational methods used. Particular attention is given to geological input into the various stages of the grade control program so as to ensure the reliability of sampling; to aid the production of bench extraction outlines; and to predict and minimize dilution and ore loss. The application of geostatistical techniques in this respect is also critically examined.
Ore reserve estimation in Los Pelambres, A Chilean porphyry copper
Authors: Faunes A. , Forkes J. , O’Leary J. 
Published: April 2008

Abstract
Los Pelambres is a world-class Chilean porphyry copper orebody located in the Andes Range adjacent to the border with Argentina at an elevation of 3100 m. It is characterized by a stock-size Tertiary granodiorite complex intruding a lower Cretaceous volcano-sedimentary sequence. Several multi-episodic stages of hypogene alteration and mineralization related to late porphyries and hydrothermal breccias occur, as well as secondary enrichment, generating a well defined orebody with bornite-chalcopyrite-chalcocite as the main copper minerals with minor molybdenite. Additionally, some gold and silver values are present. Grade zoning and kriging methods have been used to evaluate the richest east portion of Los Pelambres.
Faunal and floral indicators of ocean coastal upwelling (NW African and Peruvian Continental Margins)
Authors: Thiede J. , Jünger B. 
Published: April 2008

Abstract

Sediments under coastal upwelling regimes contain pelagic fossil assemblages that differ from those of non-upwelling coastal areas and of the open ocean. In this paper we describe the composition and biogeographical distribution of skeletal material of living planktic and benthic organisms in two of the most important coastal upwelling regions. Particular attention is paid to planktic foraminifers and pelagic gastropods off NW Africa and off NW South America. In both regions, near-surface water masses covering coastal waters of the upwelling region
per se
, of the coastal regions to the North and South of the upwelling centres as well as of the adjacent open ocean, were sampled during 1971 and 1977. The upwelled water masses were characterized by very high concentrations of radiolarians, planktic foraminifers, pteropods and small fish bones (the latter off NW South America only).

The biogeographical distribution of planktic foraminifers and pelagic gastropods can be related particularly well to upwelling. Off NW South America,
Globigerinoides ruber, Globigerina bulloides
and
Globoquadrina dutertrei
are found in high abundances near the coast. A region of high concentrations of these species extends from the areas of maximum occurrence towards the west and south into the open Pacific Ocean. Analogous biogeographical patterns can be observed off NW Africa. Concentrations of pelagic gastropods also are high in both coastal upwelling regions. Typical upwelling species are
Limacina inflata, L. trochiformis
and
Creseis acicula a.
. The biogeography of pelagic fossil groups is therefore particularly well suited to delimit the spatial extent of coastal upwelling regions.
Planktonic foraminiferal faunal and stable isotopic indices of upwelling: a sediment trap study in the San Pedro Basin, Southern California Bight
Authors: Thunell Robert , Sautter Leslie Reynolds 
Published: April 2008

Abstract

A planktonic foraminiferal faunal and stable isotopic study has been carried out on sediment trap samples collected in 1988 from the San Pedro Basin (Southern California Bight) in order to examine the response of this group of plankton to coastal upwelling. Hydrographic monitoring indicates that a period of upwelling occurred in the basin from late April to early June, with a brief spring bloom of planktonic foraminifera occurring prior to upwelling. The onset of upwelling resulted in a significant increase in total foraminiferal shell flux; the upwelling assemblage was initially dominated by
Globigerina quinqueloba
, with
Globigerina bulloides
dominating the latter half of upwelling. Following upwelling, the upper water column became thermally stratified and
Neogloboquadrina dutertrei
dominated the fauna. The observed pattern of faunal succession may be partly related to changes in food availability.

Stable isotope analyses (δ
18
O and δ
13
C) of
Neogloboquadrina pachyderma, N. dutertrei
and
G. bulloides
indicate that all three species adjust their depth habitats in response to upwelling.
Globigerina bulloides
migrates from below the thermocline to the surface at the onset of upwelling. Both
N. pachyderma
and
N. dutertrei
appear to adjust their depth habitats in order to remain within specific temperature ranges.
Oxygen and carbon isotopes in planktonic foraminifera as indicators of upwelling intensity and upwelling-induced high productivity in sediments from the northwestern Arabian Sea
Authors: Steens Tineke N. F. , Ganssen Gerald , Kroon Dick 
Published: April 2008

Abstract

Oxygen and carbon isotopes in the tests of
Globigerina bulloides
and
Neogloboquadrina dutertrei
from the Indian Ocean provide indicators for the intensity of upwelling and upwelling-related high productivity. The difference in δ
18
O between the surface dwelling
G. bulloides
and the thermocline dwelling
N. dutertrei
reflects the mixing of the water column during upwelling situations, and hence the intensity of upwelling. The difference in δ
13
C isotope distribution between the two species is smallest within upwelling areas, indicating that upwelling induced the high productivity. The two parameters are applied to Hole 728A (ODP 117), in the Arabian Sea on the continental margin of Oman. Both upwelling indicators show that from isotopic stage 2 till stage 11 upwelling was stronger during interglacial periods, and that upwelling intensified down core for the same period. In older sediments, stages 12 and 13, the signal from the upwelling indicators is reversed, showing stronger upwelling during glacials.
Physical upwelling processes, upper ocean environment and the sediment record of the southwest monsoon
Authors: Anderson David M. , Brock John C. , Prell Warren L. 
Published: April 2008

Abstract
We used a one-dimensional model of upwelling driven by the surface windfield to examine the relationship between wind-driven physical upwelling processes, changes in the plankton environment and modern (coretop) sediments in the northwest Arabian Sea. The model resolves the vertical upwelling velocity into a coastal component related to transport away from a solid boundary and a second component related to the curl in the wind stress. The coastal component is an order of magnitude larger than the curl component but restricted to <100 km offshore. In offshore waters (>100 km), upwelling is directly related to the curl in the wind stress. Model-derived upwelling is in reasonable agreement with estimates of the vertical velocity off Oman, and correlated with the cool waters and thin mixed layer found along the coast of Oman. The response of the biota to these environmental changes is observed in remotely sensed images of phytoplankton biomass during the Southwest Monsoon, and in distinct foraminifer species distributions in modern (coretop) sediments.
A lamina-scale geochemical and sedimentological study of sediments from the Peru Margin (Site 680, ODP Leg 112)
Authors: Aplin A. C. , Bishop A. N. , Clayton C. J. , Kearsley A. T. , Mossmann J.-R. , Patience R. L. , Rees A. W. G. , Rowland S. J. 
Published: April 2008

Abstract
Individual laminae (mm-cm) were isolated from late Pliocene-Holocene sediments cored at Site 680 during ODP Leg 112 (Peru upwelling region). At all depths, individual laminae alternate between (1) pale, high porosity, clay-poor, diatom ‘framework’ oozes containing a high proportion of complete, well preserved diatom frustules and (2) dark, low porosity diatomaceous muds containing abundant diatom debris and foraminifer tests. In some instances, detrital-rich laminae with low amounts of diatom debris were also observed.
Hydrogen-rich organic matter is finely disseminated throughout the sediments, perhaps occurring as coatings on detrital and biogenic grains. Both carbon isotopic and pyrolysis-GCMS analyses suggest that the organic matter is derived mainly from a marine algal and/or bacterial input. Py-GCMS further shows that, even in the sediments from 4.91 mbsf, the organic matter is significantly altered from the composition of living organisms. Only in two organic-lean Pliocene samples was there any sign of a significant input of terrestrial organic matter. Relative to laminae deposited during the Pleistocene-Holocene, late Pliocene laminae are depleted in TOC. This may reflect variations in primary productivity. TOC contents also vary between adjacent diatomaceous mud laminae in Pleistocene-Holocene sediments. In these laminae, TOC is inversely proportional to diatom abundance (which is believed to be related to productivity) but correlates positively with detrital content. Variations in the TOC content of closely spaced laminae is apparently not controlled by variations in productivity or preservation, but probably by variations in the TOC content of particulate matter reaching the sediment-water interface.

Some parameters (organic S/C; δ
34
S) vary on a lamina scale — no larger scale trends are apparent. These variations are presumably the result of short-term, local changes in diagenetic conditions and are hard to quantify. In these H
2
S-rich sediments, differential uptake of sulphur into organic matter may be caused by variations in the availability of specific, reactive inorganic sulphur species, perhaps polysulphides.

This study shows that conventional geochemical analysis of bulk, or of widely spaced samples can hide significant variations in sediment composition and inferred palaeoceanographical conditions. Although bulk samples may be used to determine the gross characteristics of a sedimentary sequence, fine-scale sampling is needed to define the processes which determined those characteristics.
The spatial distribution and seasonal succession of planktonic foraminifera in the California Current off Oregon, September 1987 – September 1988
Authors: Ortiz Joseph D. , Mix Alan C. 
Published: April 2008

Abstract

Preliminary results are presented from the September 1987 to September 1988 deployment of the Multitracers Project, a moored sediment trap experiment in the California Current. Three sediment trap moorings were deployed on a transect off Cape Blanco at 130, 280, and 650 km offshore. The seasonal distribution of foraminifers in the California Current at 42°N reflect variations in the temperatures and water masses present at each site. The winter assemblage of foraminifers at the sites 130 and 280 km offshore comprise mainly the subarctic/transitional species:
N. pachyderma
(right),
N. dutertrei, G. bulloides, G. quinqueloba
and
G. glutinata
. From late June to September 1988 at the site 130 km offshore,
G. bulloides, G. falconensis, N. pachyderma
(left) and the P-D intergrade category record high fluxes, apparently in response to upwelling conditions. The subtropical species
O. universa, G. ruber
and
T. humilis
are most important at the site 650 km offshore. The foraminiferal communities present from September 1987 to September 1988 off Cape Blanco seem to be more diverse but less productive than assemblages from the Alaskan Gyre at Station P (45°N, 150°W) as described in the literature.
The palynological expressions of post-Palaeogene upwelling: a review
Authors: Powell A. James , Lewis Jane , Dodge John D. 
Published: April 2008

Abstract
This paper reviews the known palynological expressions of post-Palaeogene upwelling, and changes in upwelling. In Plio-Pleistocene upwelling regimes, levels of amorphogen tend to swamp other palynoclasts present; the application of transmission electron microscopy has great potential for elucidating the origins of amorphogen. The recovery of foraminiferal test linings may be controlled by their progressive microbial destruction; the more juvenile stages in the ontogenetic record stand the greatest chance of preservation. The study of dinoflagellate cyst biofacies offers the greatest potential for palynological characterization and interpretation of post-Palaeogene upwelling systems. Cysts of heterotrophic peridiniacean dinoflagellates (P-cysts) tend to dominate cysts of autotrophic gonyaulacacean forms (G-cysts). The ratio of P-cysts to G-cysts (P/G ratio) is therefore considered to be a useful indicator of variable upwelling strength in these settings, reflecting the degree of water column turbulence. It is uncertain to what degree alynological patterns recognizable in one system are representative of other contemporaneous upwelling regimes. Nevertheless, palynological studies of upwelling systems should be used to interpret geochemical data and thereby provide a tangible link between cause (palaeobiological) and effect (geochemical).
Variations in the content and composition of organic matter in sediments underlying active upwelling regimes: a study from ODP Legs 108, 112, and 117
Authors: Ten Haven H. L. , Eglinton G. , Farrimond P. , Kohnen M. E. L. , Poynter J. G. , Rullkötter J. , Welte D. H. 
Published: April 2008

Abstract

An overview is presented of organic geochemical studies on sediments underlying the active upwelling cells off Northwest Africa (ODP Leg 108; Site 658), off Peru (Leg 112; Sites 679, 681, 684, 686) and off Oman (Leg 117; Sites 723, 725, 728). The investigated sediments are all characterized by high organic carbon contents (0.5–9% C
org
), being the sedimentary expression of an increased primary bioproductivity induced by upwelling currents of deep nutrient-rich waters. The organic matter is predominantly of marine origin with variable admixtures of a terrigenous component; the highest relative contribution is found at Site 658. The extractable lipids are composed of a wide variety of compounds, of which the most characteristic and abundant compounds were quantified. Long-chain unsaturated ketones usually dominate. Steroids, alkanediols and their corresponding keto-ols are also present in high concentrations, although strong variations in their abundances were noted. In addition, organic sulphur compounds are omnipresent and reveal strong variations in their distribution, but do not make a major contribution to the total amount of extractable lipids.
Carbon/sulphur/iron relationships in upwelling sediments
Authors: Morse John W. , Emeis Kay C. 
Published: April 2008

Abstract
Carbon/sulphur/iron relationships in sediments from beneath three upwelling areas (Benguela, Peru and Oman) were investigated using DSDP and ODP cores. The three areas displayed markedly different C/S/Fe characteristics. Metabolizable organic matter appears to limit production of reduced sulphur in the Benguela upwelling area sediments, as evidenced by incomplete reduction of dissolved sulphate. On the Peru shelf infusion of a sulphate-containing brine at depth has a major influence on diagenesis.
Weight ratios of organic carbon to reduced inorganic sulphur are generally higher in sediments from upwelling areas than in normal marine sediments. C/S ratios generally increase with increasing organic carbon concentration in upwelling sediments. This does not appear to be the result of limited availability of reactive iron. Both carbon and reduced sulphur accumulation rates are well correlated with sediment accumulation rates, but are higher than in non-upwelling sediments having similar accumulation rates.
Strong deglacial minimum in the δ
13
C record from planktonic foraminifera in the Benguela upwelling region: palaeoceanographic signal or early diagenetic imprint?
Authors: Schneider R. , Dahmke A. , Kölling A. , Müller P. J. , Schulz H. D. , Wefer G. 
Published: April 2008

Abstract

A strong deglacial decrease in the δ
13
C values of the planktonic foraminifera
G. inflata
and
G. bulloides
, spanning a 1000-year period, was measured in a core from the Benguela upwelling region. The deglacial δ
13
C minimum exceeds background values by more than −1‰, and is between −1.6 to −2.0‰ below Holocene values. The unusual low δ
13
C values could reflect a change in the isotopic composition of the upwelled South Atlantic Central Water (SACW) and/or changes in the stratification of the surface waters in the Benguela coastal upwelling region. The observed δ
13
C decrease correlates with a proposed zone of authigenic CaCO
3
precipitation at 6 m depth in the anaerobic sediments. This raises the question whether the δ
13
C minimum was caused by diagenetic alteration of the δ
13
C record or not. Calculations based on estimated interstitial water δ
13
C
TCO2
values and flux rates of Ca predict a 5% authigenic CaCO
3
precipitation additional to the primary CaCO
3
content in the sediment, which could account for an average diagenetic imprint of −1.0‰ δ
13
C
CaCO3
if precipitated on foraminiferal tests. However, missing visual evidence (SEM) for authigenic CaCO
3
phases greatly weakens the case for diagenetic causes for the negative δ
13
C spike. The deglacial negative δ
13
C spike is therefore assumed to be a primary palaeoceanographic signal.
Calcareous nannofossils of Plio-Pleistocene sediments from the northwestern margin of tropical Africa
Authors: Pujos Annick 
Published: April 2008

Abstract
Coccoliths are skeletal remains of organisms living in the uppermost part of the oceans, so they reflect the climatological and hydrological variations of the uppermost water layers. The main goal of the present study is to use their fossil remains (calcareous nannofossils) to capture information about the environment where they lived for the last 700 000 years. The work is based on a study of sediment from Site 658, ODP Leg 108 located in a major upwelling area in the northeastern tropical Atlantic, close to the African continent. The hydrological and atmospherical conditions of the area are complex: seasonally windy and alternatively humid and arid. Downcore the effects of these changes are complicated by the presence of climatic stages including various glacial/interglacial alternations.

The interpretation of Plio-Pleistocene climatic history at Site 658 is based on analysis of abundance matrices (calcareous nannofossils as well as other <25 μm organic and inorganic elements) and of two nannofossil-based transfer functions (giving estimates for summer-winter temperatures, summer-winter salinities and productivity). The nannofossils most useful for paleoecological interpretation proved to be
Rhabdosphaera
(related to increased temperature and decreased productivity),
Coccolithus pelagicus
(related to sharp decreases in temperature and inversely to salinity),
Syracosphaera
(related to increased salinity) and
Helicopontosphaera
(related to sharp decreases in salinity and increased productivity).

A tentative paleoenvironmental and paleoecological model is given for a typical glacial/interglacial alternation. During
glacial
periods the African continent was arid, with seasonal winds blowing towards the ocean, and the uppermost oceanic waters showing increased salinity. At first oceanic temperatures were low, and organic matter linked with fecal pellets was abundant due to wind-induced upwelling; temperature then increased slightly, before decreasing at the end of the glacial period under the influence of northern ice sheets. At the
glacial/interglacial boundary
, rainy monsoons caused strong and sudden increased runoff, which lowered salinity;
interglacial
time was characterized by low salinity surface waters. As interglacials began, fluvial outflows supplied abundant inorganic and organic matter, while the Canary Current brought cooler waters south from northern latitudes, and there was a short record of upwelling. Then, temperature increased slowly, as the area became dominated by tropical waters.
Miocene intensification of upwelling along the California margin as recorded in siliceous facies of the Monterey Formation and offshore DSDP sites
Authors: White Lisa D. , Garrison Robert E. , Barron John A. 
Published: April 2008

AbstractDiatomaceous sediments and their diagenetic equivalents in the Monterey Formation record a variable history of upwelling along the California margin. Distrinctive dark opal-CT and quartz chertz found in distal basins of the Monterey Formation are the result of burial diagenesis of pure biosiliceous oozes (biosiliceous oozes without significant admixtures of clay) and are therefore evidence of intensified coastal upwelling during the early middle Miocene. Dating of six sections of the Monterey Formation, largely by diatom biostratigraphy, suggests that at the Point Reyes and Point Año Nuevo sections in north-central California, the age of the earliest chert intervals is between 13.8 and 15.0 Ma, and 14.3 and 14.8 Ma, respectively. In south-central California, ages from the Shell Beach, Mussel Rock, and Lions Head sections imply that the age of the base of the chert intervals is between 12.7 and 13.3 Ma. Both ages correlate to an early middle Miocene high latitude cooling step that resulted in more vigorous surface water circulation, upwelling of nutrient-rich waters, and increased biosiliceous sedimentation in the North Pacific. The north-south difference in age of the base of the chert interval probably reflects a progressive intensification of the California Current from 15.0 to 12.7 Ma.The age of the onset of biosiliceous sedimentation at DSDP sites of the northeastern Pacific is also generally younger at the more southern sites; however, these particular DSDP sites were located some distance from the centres of coastal upwelling and are not as reliable indicators of the intensification of upwelling along the California margin.