A Methodology for Sensitivity Analysis Based on Regression: Applications to Handle Uncertainty in Natural Resources Characterization     

Yevgeniy Zagayevskiy  Clayton V. Deutsch 《Natural Resources Research》2015,24(3):239-274

  相似文献   

A Hybrid Estimation Technique Using Elliptical Radial Basis Neural Networks and Cokriging     

Samson  Matthew  Deutsch  Clayton V. 《Mathematical Geosciences》2022,54(3):573-591

Mathematical Geosciences - Mineral resource estimation is an integral part of making informed decisions while evaluating a mining operation’s feasibility. Geostatistical tools estimate...  相似文献   

Implementation of the Iterative Proportion Fitting Algorithm for Geostatistical Facies Modeling     

Yupeng Li  Clayton V. Deutsch 《Natural Resources Research》2012,21(2):221-231

In geostatistics, most stochastic algorithm for simulation of categorical variables such as facies or rock types require a conditional probability distribution. The multivariate probability distribution of all the grouped locations including the unsampled location permits calculation of the conditional probability directly based on its definition. In this article, the iterative proportion fitting (IPF) algorithm is implemented to infer this multivariate probability. Using the IPF algorithm, the multivariate probability is obtained by iterative modification to an initial estimated multivariate probability using lower order bivariate probabilities as constraints. The imposed bivariate marginal probabilities are inferred from profiles along drill holes or wells. In the IPF process, a sparse matrix is used to calculate the marginal probabilities from the multivariate probability, which makes the iterative fitting more tractable and practical. This algorithm can be extended to higher order marginal probability constraints as used in multiple point statistics. The theoretical framework is developed and illustrated with estimation and simulation example.  相似文献   

From Tethys to Eastern Paratethys: Oligocene depositional environments, paleoecology and paleobiogeography of the Thrace Basin (NW Turkey)     

Yeşim İslamoğlu  Mathias Harzhauser  Martin Gross  Gonzalo Jiménez-Moreno  Stjepan Coric  Andreas Kroh  Fred Rögl  Jan van der Made 《International Journal of Earth Sciences》2010,99(1):183-200

The Oligocene depositional history of the Thrace Basin documents a unique paleogeographic position at a junction between the Western Tethys and the Eastern Paratethys. As part of the Tethys, shallow marine carbonate platforms prevailed during the Eocene. Subsequently, a three-staged process of isolation started with the Oligocene. During the Early Rupelian, the Thrace Basin was still part of the Western Tethys, indicated by typical Western Tethyan marine assemblages. The isolation from the Tethys during the Early Oligocene is reflected by oolite formation and endemic Eastern Paratethyan faunas of the Solenovian stage. The third phase reflects an increasing continentalisation of the Thrace Basin with widespread coastal swamps during the Late Solenovian. The mollusc assemblages are predominated by mangrove dwelling taxa and the mangrove plant Avicennia is recorded in the pollen spectra. The final continentalisation is indicated by the replacement of the coastal swamps by pure freshwater swamps and fluvial plains during the Late Oligocene (mammal zone MP 26). This paleogeographic affiliation of the Thrace Basin with the Eastern Paratethys after ~32 Ma contrasts all currently used reconstructions which treat the basin as embayment of the Eastern Mediterranean basin.  相似文献   

Ice‐borne prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations     

Martin Grosjean  Peter J. Suter  Mathias Trachsel  Heinz Wanner 《第四纪科学杂志》2007,22(3):203-207

During the hot summer of 2003, reduction of an ice field in the Swiss Alps (Schnidejoch) uncovered spectacular archaeological hunting gear, fur, leather and woollen clothing and tools from four distinct windows of time: Neolithic Age (4900 to 4450 cal. yr BP), early Bronze Age (4100–3650 cal. yr BP), Roman Age (1st–3rd century AD), and Medieval times (8–9th century AD and 14–15th century AD). Transalpine routes connecting northern Italy with the northern Alps during these slots is consistent with late Holocene maximum glacier retreat. The age cohorts of the artefacts are separated which is indicative of glacier advances when the route was difficult and not used for transit. The preservation of Neolithic leather indicates permanent ice cover at that site from ca. 4900 cal. yr BP until AD 2003, implying that the ice cover was smaller in 2003 than at any time during the last 5000 years. Current glacier retreat is unprecedented since at least that time. This is highly significant regarding the interpretation of the recent warming and the rapid loss of ice in the Alps. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Two Artifacts of Probability Field Simulation   总被引：1，自引：0，他引：1  

Michael J. Pyrcz  Clayton V. Deutsch 《Mathematical Geology》2001,33(7):775-799

Probability field simulation is being used increasingly to simulate geostatistical realizations. The method can be faster than conventional simulation algorithms and it is well suited to integrate prior soft information in the form of local probability distributions. The theoretical basis of probability field simulation has been established when there are no conditioning data; however, no such basis has been established in presence of conditioning data. Realizations generated by probability field simulation show two severe artifacts near conditioning data. We document these artifacts and show theoretically why they exist. The two artifacts that have been investigated are (1) local conditioning data appear as local minima or maxima of the simulated values, and (2) the variogram model in range of conditioning data is not honored; the simulated values have significantly greater continuity than they are supposed to. These two artifacts are predicted by theory. An example flow simulation study is presented to illustrate that they affect more than the visual appearance of the simulated realizations. Notwithstanding the flexibility of the probability field simulation method, these two artifacts suggest that it be used with caution in presence of conditioning data. Future research may overcome these limitations.  相似文献   

Kriging with strings of data   总被引：1，自引：0，他引：1  

Clayton V. Deutsch 《Mathematical Geology》1994,26(5):623-638

The concept of a random function and, consequently, the application of kriging cells for the implicit assumption that the data locations are embedded within an infinite domain. An implication of this assumption is that, all else being equal, outlying data locations will receive greater weight because they are seen as less redundant, hence, more informative of the infinite domain. A two- step kriging procedure is proposed for correcting this siring effect. The first step is to establish the total kriging weight attributable to each string. The distribution of that total weight to the samples in the string is accomplished by a second stage of kriging. In the second stage, a spatial redundancy measure r_(n) is used in place of the covariance measure in the data-data kriging matrix. This measure is constructed such that each datum has the same redundancy with the (n)data of the string to which it belongs. This paper documents the problem of kriging with strings of data, develops the redundancy measure r_(n),and presents a number of examples.  相似文献   

A new precambrian paleomagnetic pole for northern Europe     

G.S. Murthy  E.R. Deutsch 《Physics of the Earth and Planetary Interiors》1975,11(2):91-96

A paleomagnetic study was made of the granitic rock farsundite, exposed in southern Norway. An objective was to test the contemporaneity of this body with the neighbouring Egersund anorthosite of presumed age about 900 m.y. Two of the nine sites sampled were rejected, as the magnetization was dominantly unstable. At the seven other sites, this unstable component was either absent or it could be equally well removed by AF or thermal demagnetization: after AF treatment, all samples from these sites were left with a very stable remanence, directed steeply upwards. This magnetization was probably acquired at the time of either emplacement or recrystallization of the farsundite. A magnetic test for anisotropy indicated that the stable remanence is misaligned with the ancient Earth's field direction by about 3°, apparently due to layering of the rock fabric. After correction for this anisotropy, the mean direction from the seven sites is D = 341°, I = 82.2°, k = 142, α = 5.0°, corresponding to a paleomagnetic north pole at 43.3°S, 166.0°W, dp = 9.3°, dm = 9.7°, which lies on Spall's European polar wandering curve. The farsundite pole is not significantly different from a pole position based on the Egersund anorthosite, which supports the supposition that the two rock formations are cogenetic.  相似文献   

On the complex magnetic behaviour of titanomagnetites     

C. Radhakrishnamurty  S. D. Likhite  E. R. Deutsch  G. S. Murthy 《Physics of the Earth and Planetary Interiors》1982,30(4):281-290

The bulk magnetic properties, including Curie temperature, susceptibility and hysteresis at various temperatures, and the Mössbauer spectra of coarse synthetic members of the titanomagnetite series are compared as a function of titanium content, using some previously reported and some new results. It has been noted previously that the titanium-rich members fail to show the expected “true multidomain” behaviour observed in pure magnetite. One possible explanation is that the behaviour observed may be due to a tendency to inhibit domain wall formation in some titanomagnetites. In this paper we discuss some other possible mechanisms to account for the magnetic properties of such titanomagnetites observable even when domain-wall-related structures do form in them. These mechanisms suggest that magnetocrystalline anisotropy and its temperature dependence in titanomagnetites may be related to local magnetic inhomogeneities, and do not depend only on crystal structure as in the case of classical ferromagnetic materials.  相似文献   

Reservoir Characterization of McMurray Formation by 2D Geostatistical Modeling     

Weishan Ren  Jason A. Mclennan  Oy Leuangthong  Clayton V. Deutsch 《Natural Resources Research》2006,15(2):111-117

There is a need to estimate reserve uncertainty for large lease areas. Detailed 3D models of heterogeneity are not necessarily required, but there is a need to integrate all available data into an in-situ reserve estimate with uncertainty. A 2D mapping approach is presented to appraise reserves accounting for multiple variables, multiple data sources, and uncertainty. The approach can be considered in three primary steps: (1) Bayesian updating is used to determine local distributions of uncertainty for each primary variable while integrating multiple secondary information, (2) matrix simulation is employed to jointly and simultaneously simulate multiple collocated variables to determine a derived variable such as OOIP, and (3) probability field simulation then is applied to permit joint simulation of multiple locations. This methodology permits local and global uncertainty assessment while integrating multiple sources of information. An application to the McMurray Formation in Alberta, Canada is demonstrated.  相似文献