Datum Planes Research Articles

Experimental evaluation of terrestrial LiDAR-based surface roughness estimates

The rapid proliferation of portable, ground-based light detection and ranging (LiDAR) instruments suggests the need for additional quantitative tools complementary to the commonly invoked digital terrain model (DTM). One such metric is surface roughness, which is a measure of local-scale topographic variability and has been shown to be effective for mapping discrete morphometric features, i.e., fractures in outcrop, landslide scarps, and alluvial fan deposits, to name a few. Several surface roughness models have been proposed, the most common of which is based on the standard deviation of point distances from a reference datum, e.g., DTM panels or best-fit planes. In the present work, we evaluate the accuracy of these types of surface roughness models experimentally by constructing a surface of known roughness, acquiring terrestrial LiDAR scans of the surface at 25 dual-axis rotations, and comparing surface roughness estimates for each rotation calculated by three surface roughness models. Results indicate that a recently proposed surface roughness model based on orthogonal distance regression (ODR) planes and orthogonal point-to-plane distance measurements is generally preferred on the basis of minimum error surface roughness estimates. In addition, the effects of terrestrial LiDAR sampling errors are discussed with respect to this ODR-based surface roughness model, and several practical suggestions are made for minimizing these effects. These include (1) positioning the laser scanner at the largest reasonable distance from the scanned surface, (2) maintaining half-angles for individual scans at less than 22.5°, and (3) minimizing occlusion (shadowing) errors by using multiple, merged scans with the least possible overlap.

Upper Campanian-lower Maastrichtian planktonic foraminifers and biostratigraphy of the Moni Formation, southern Cyprus

The first data on the taxonomic composition and stratigraphic range of the late Campanian planktonic foraminifers encountered in the middle and upper parts of the Moni Formation, southern Cyprus, are reported. Finds of planktonic foraminifers are associated with the bentonitic clay that composes the matrix of the Moni Formation. The planktonic foraminiferal assemblages revealed are very similar to those from the Kannaviou Formation, western Cyprus, but they are more diverse and yield several key species missing in the Kannaviou sediments. The planktonic foraminiferal assemblages discussed are referred to the Globotruncana aegyptiaca Zone and to the lowermost Gansserina gansseri Zone of the upper upper Campanian of the standard scale. The intraregional correlation of the Moni sections, depth of erosion of the upper part of the formation, and its relationship with the Kannaviou Formation have been refined. When subdividing the upper Campanian sediments based on planktonic foraminifers it is suggested that additional datum planes are used, such as the FADs of Globotruncanella citae and Trinitella scotti. For tracing the Campanian-Maastrichtian boundary (GSSP), attention should be paid to the LADs of Globotruncana bulloides and Contusotruncana fornicata and the potential use of Globotruncanita (Elevatotruncana) eolita sp. nov. should be assessed. It is shown that subfamily Archaeoglobigerininae Salaj, 1987, emend. O. Korchagin is the older synonym of subfamily Archaeoglobigerininae Georgescu, 2005. Two poorly known and three new planktonic foraminiferal species are described.

Stratigraphic relationships between the last occurrence of Neogloboquadrina inglei and marine isotope stages in the northwest Pacific, D/V Chikyu Expedition 902, Hole C9001C

The stratigraphic relationships between the last occurrence (LO) of the planktic foraminiferan Neogloboquadrina inglei in the middle Pleistocene and established marine isotope stages (MIS) was investigated using a 365-m-long sediment core from a continental slope in the northwest Pacific near the Shimokita Peninsula, Japan. Two tephra layers (Shikotsu-Daiichi and Aso-4 tephras) and two nannofossil datum planes (first occurrence of Emiliania huxleyi and LO of Pseudoemiliania lacunosa) were used as age- control points, and the oxygen isotope stratigraphy of Hole C9001C was established by correlating the oxygen isotope values of the benthic foraminiferan Uvigerina akitaensis with the standard oxygen isotope curve LR04. Hole C9001C provides the first continuous, high-sedimentation-rate (20-90 cm/kyr) record from MIS 18 to present in the northwestern Pacific near Japan. The stratigraphic position of the LO of N. inglei is in late MIS 16 or near the MIS 16/15 boundary.

Stratigraphy and major paleoenvironmental changes in the Sea of Okhotsk during the last million years inferred from radiolarian data

The radiolarian distribution is studied in Core IMAGES MD01-2415(46-m-long) from the central Sea of Okhotsk. The obtained data made it possible to refine the regional biostratigraphy and document the major paleoenvironmental changes in the basin in the last million years. In total, 17 radiolarian datum planes are defined with 12 of them being new. Their number exceeds that previously established for different fossil groups in the Subarctic Pacific for this period. Radiolarian datum planes are usually confined to the main boundaries and Quaternary climatic events. The analysis of the radiolaria distribution reveals several major paleoenvironmental shifts in the sea that occurred 950, 700, and 420-280 ka ago and are correlative with regional and global phases of the Middle Pleistocene climatic revolution.

Setup planning for machining the features of prismatic parts

This paper focus on the development of a formalized procedure for automatic generation of feasible setups and then to select an optimal setup plan for machining the features of a given prismatic part. The proposed work simultaneously considers the basic concepts of setup planning from both machining and fixturing viewpoints in order to formulate feasible setup plans. The tasks that are performed are: (a) identifying groups of features that can be machined in a single setup, (b) determining a suitable work piece orientation, i.e. the suitable datum planes for each setup, (c) determining all the feasible setup plans to machine the given set of features of prismatic parts, and (d) evaluating the feasible setup plans on the basis of technological (available tolerance) and economical conditions (total setup time). For the proposed work the authors have introduced four new concepts namely, ‘surface fit for location’, ‘primary group’ ‘secondary group’, and ‘eligible group’. The first concept plays an important role in the identification of suitable faces of the part for positioning, clamping and supporting. The other three help in clustering of features, which can be converted in to candidate setups.

Preliminary study on the comparison and analysis of the digital maxillary alveolar casts

To develop a three-dimensional (3-D) comparison and measuring techniques to analyze changes in palatal forms of the serial maxillary alveolar cast and to evaluate the significance of the different reference change indexes. Following digitizing the casts with a 3-D laser scanner and using reverse engineering software Geomagic Studio 7.0 for a pair of 3-D digital maxillary alveolar cast of an infant of UCLP before and after cheiloplasty, a pair of cast surfaces were reconstructed. The reference points and the character lines were extracted. The model coordinate system and the datum planes were established on the basis of reference points extracted. The newly developed analysis technique completed 3-D comparison of palatal forms of UCLP infants before and after cheiloplasty. Distances and volumes changes between the surfaces were determined and expressed graphically. With establishing the model coordinate system and the datum plane, it is possible to visualize the comparison outcome of the reference change indexes longitudinally. The various reference change indexes may reflect the trend of the infant maxillary growth.

A web-based 3D virtual technologies for developing product information framework

Information technologies and the web are challenging, and changing theway industry works. It is believed that web-based 3D interface can be applied to strengthen the interactive visualization and manipulation of products. In this research, a web-based 3D virtual technologies for developing product information framework is applied in automotive electric system. It is very convenient to share with different partners (e.g., co-designers, manufacturers, customers, etc.) via the web for viewing the aesthetic functions, and verifying its related design functions. The overall procedures are listed: First, build CAD models of automotive electric system (including assemble parts and their components) through CAD system, then store them in a relational database. Second, transforming the CAD models users click into virtual reality modeling language (VRML) objects, it can be visualized graphically and animated interactively using a web browser with a VRML plug-in. Finally, operate the VRML objects by Java Language for the different purposes. Due to the technologies that are applied, many interactive modes are generated in cyberspace. Displaying the exploding process of 3D assemble part on the browser, assigning any component of assemble part through the mouse chick directly to display design details, e.g., dimensions, tolerances, datum planes, material, other references, etc. by retrieving the corresponding data from database, and building 2D projected views automatically follow the 3D viewpoint that users assign.

Surface roughness effects onmicroparticle adhesion

A new self-consistent model is developed to treat the static contact of a microparticle with a flat barrier in the presence of molecular adhesion and surface roughness. Separation between their mean datum planes is modeled considering the elastic deformation of the microparticle and surface. The contact pressure is computed from the Lennard-Jones law following the Derjaguin approximation. The elastic deflection of the mean datum plane is calculated from the effective pressure by the half-space elastic theory. Roughness is modeled by introducing a Gaussian distribution to the gap between the surfaces. An effective pressure is defined as the statistical average of the contact pressure over the roughness heights. A solution satisfying all of the above conditions gives a self-consistent method of modeling adhesion between the microparticle and the flat barrier. Using collocation methods the equations are discretized as a large system of nonlinear algebraic equations. A continuation method is used to find the multiple numerical solutions for the mean separation and the effective contact pressure. Finally, adhesive contacts of both smooth and rough surfaces are simulated in a comparative manner to elucidate the features of surface roughness in the presence of molecular adhesion. The standard deviation of the Gaussian distribution is used as a parameter to assess the effects of roughness on the pull-off force. It is shown that increasing surface roughness significantly reduces the pull-off force and decreases the tendency for the microsphere to snap-on and snap-off.

Injection moulding simulation of filling and post-filling stages based on a three-dimensional surface model

Filling and post-filling simulation packages of injection moulding have had success in predicting the behaviour of a polymer melt in extremely complicated geometries. Most of the current numerical solutions are based on a hybrid finite element-finite difference scheme and the middle-plane model. This middle-plane model leads to substantial defects during applications of the simulation tools. Instead of using the middle plane as the datum plane, the surfaces of the cavity are used as datum planes in this paper. Additional boundary conditions in the gapwise direction are employed to keep the flows in the surfaces at the same section coordinated. Also, comparisons with the experimental results obtained with instrumented test mould and C-Mold results show that this presented simulation is correct and reliable.

A numerical simulation of the filling stage in injection molding based on a surface model

AbstractComputer simulation packages have had success in predicting filling behavior in extremely complicated geometries. However, most of the current numerical implementation is based on a hybrid finite‐element/finite‐difference solution with the middle‐plane model. This kind of model leads to some inconvenience in applications. Instead of using the middle‐plane as the datum plane, the surfaces of the cavity are used as datum planes in this article. Additional boundary conditions in the gapwise direction are employed to keep the flows in the surfaces at the same section coordinative. Comparisons with experimental results obtained with an instrumented test mold and C‐Mold results show good agreement in terms of pressure traces and melt‐front advancement. It is demonstrated that the present formulation is well suited to handle cavities generated directly by current CAD systems. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 125–131, 2001

三国山地平標山に分布する第四紀末期のテフラ層

Sum of eleven tephras occur in Mount Tairappyo (36° 48' N, 138° 49' E, 1, 984 m asl) ofthe Mikuni Mountains, central Honshu Island, Japan. Although these tephras are thought to be useful for Quaternary studies in this area, they have not been described systematically. We investigated stratigraphy, lithofacies, petrographic properties, and refractive indices of volcanic glass shards and phenocrysts of these tephras in order to correlate them with the known ones. We also estimated the calendric ages of the tephras based on their stratigraphy and the radiocarbon ages in the previous references.The followings were identified : 1) the Haruna-Futatsudake-Ikaho as 1.44 ka, 2) the Haruna-Futatsudake-Shibukawa as 1.47 ka, 3) the Myoko-Otagirigawa as 4.7 ka, 4) the Asama-Tairappyosan 1 as 4.9 ka, 5) the Asama-Tairappyosan 2 as 6.3 ka, 6 and 7) the Myoko-Akakura and the Asama-Tairappyosan 3 as 6.6 ka, 8) the Asama-Tairappyosan 4 as 6.8 ka, 9) the Kikai-Akahoya as 7.2 ka, 10) the Asama-Tairappyosan 5 as 7.5 ka, and 11) the Asama-Kusatsu as 16 ka.Among them, the Myoko-Akakura and the Asama-Tairappyosan 3 are very unique. The former overlies the latter without intercalation of soil layers, and these two tephras form a thin layer. A set of the two can be correlated with the tephra X found from the Ozegahara bog about 60 km east of Tairappyo. Depositional conditions of these tephras imply that the eruption of Myoko volcano followed that of Asama without long interval, possibly less than few years, in the mid Holocene. A thin layer composed of the Myoko-Akakura and the Asama-Tairappyosan 3 is important as a key bed, as well as the Haruna-Futatsudake-Ikaho, the Kikai-Akahoya, and the Asama-Kusatsu all of which have been described as wide spread tephras. All the tephras provide Quaternary studies in this area with datum planes.

Upper Neogene and Quaternary stratigraphy in the Kakegawa district based on the calcareous nannofossil datum planes:With reference to the stratigraphic position of the Tamari Formation

Upper Neogene and Quaternary stratigraphy in the Kakegawa district based on the calcareous nannofossil datum planes:With reference to the stratigraphic position of the Tamari Formation

Forestepping-backstepping stacking pattern of volcaniclastic successions: Roccamonfina volcano, Italy

We use Unconformity Bounded Stratigraphic Units UBSU. to reconstruct the chronostratigraphy of volcaniclastic deposits of Roccamonfina Volcano southern Italy. Significant discontinuities of different hierarchical order in the stratigraphic succession of the volcano have allowed us to identify the UBSU supersynthems, synthems and subsynthems. The hierarchical order has been determined by the importance and duration of the discontinuities bounding such units and by their geographic distribution. Supersynthems are bounded by regional-scale unconformities that may correspond to important tectonic events, changes in the style of eruptive activity or volcano-tectonic collapses. Synthems are bounded by unconformities marked by paleosols that are representative of considerable hiatus and extended all over the synthem. They are composed of complex sequences of depositional units. At Roccamonfina the synthems reveal cyclical eruptive activity. Unconformities bounding the subsynthems have been recognized through a detailed facies analysis. More than 100 stratigraphic sections have been analyzed and correlated, restoring them to single successive datum planes. It has been possible to reconstruct the original stratigraphic relationships, the geometry of the units, and the effects of syn-eruptive tectonic activity. This procedure revealed that the unconformity surfaces bounding depositional units show different physical expression in the proximal, medial and distal areas: a. erosive surfaces may become amalgamation surfaces; b. amalgamation of several depositional units can locally produce a single lithostratigraphic unit. In this case the unconformity surfaces bounding the units can be identified by the presence of discontinuous pumice and lithic concentration zones; c. non-depositional surfaces in proximal areas bypassing surfaces. or in interfluve areas may correspond to downslope deposits; d. unconformity surfaces can bound different lithostratigraphic units that are the result of down-current facies variation. The pyroclastic units at Roccamonfina are organized as forestepping-backstepping sequences. We interpret this organization as resulting from waxing-waning processes associated with eruption and emplacement. In fact, the internal geometry of each synthem indicates a forestepping phase until the maximum eruption rate is achieved; as it later declines deposition occurs upslope backstepping. This mechanism is also reproduced at smaller scale within each subsynthem. The forestepping-backstepping organization of the deposits provides an explanation for the variability of physical, chemical and sedimentological parameters observed in the Roccamonfina volcaniclastic deposits.

Early Pleistocene chronology of the Vrica Section (Calabria, Italy)

Two alternative age models are presented for the Pleistocene part of the Pliocene‐Pleistocene boundary stratotype section at Vrica (Calabria, southern Italy). Both age models, or chronologies, are based on the correlation of the characteristic sapropel pattern to the summer insolation time series of astronomical solution La90. The first age model is based on the assumption that the succession is continuous, whereas a global near synchroneity of the base of large‐sized Gephyrocapsa in oxygen isotope stages 48–49 is assumed in the second model. This model implies that a major hiatus with exactly the same age and duration is present in both the Vrica and Singa sections. Cross‐spectral analysis between sea surface temperature and δ18O time series and the summer insolation target yields highly significant coherencies in the precession and obliquity frequency bands of the spectrum in cases where the continuous age model is applied but results in less significant coherencies in cases where the alternative age model is applied. According to the continuous model, the position of almost all calcareous plankton datum planes relative to the isotope stages is consistent with that found in the adjacent northern Atlantic. The only marked exception is the base of large Gephyrocapsa, which is found in stage 55 in the Mediterranean, whereas it occurs in stage 48 (or top 49) in the open ocean. The alternative age model solves the large Gephyrocapsa discrepancy but leads to significant discrepancies in the position of other calcareous plankton events. On the basis of these data sets, it is not justified to conclude which age model is correct, although most arguments are in favor of the continuous age model. This model is also supported by shipboard results from Ocean Drilling Program Legs 154 and 160 sites.

陸橋とヒトと生物の渡来 中期更新世の後半以降のナンノ化石と火山灰の連結層序 大阪湾泉州沖を例として

In the Quaternary stratigraphy, nannofossils serve superior transoceanic datum planes in open sea and fall tephra give the most reliable marker horizons in and around near shore area. Especially, island arcs in the western margin of the Pacific are suitable area to constract the combined stratigraphy which mediates both datum planes.In the Osaka bay area, a new airport plan was started in 1981. On the course of geological survey, some long cores were taken from the area. In the cores Brs. 56-9, 57-5, 57-9, 57-30 and H-6 are very interesting for the present study. Nakaseko et al. (1984 b) defined the late Pleistocene sequence of off Senshu as the Senshu-oki Group and devided it the lower, Senshu-oki and the upper, Kuhko-shima Formations. Then, they separated the Kuhko-shima Formation to eleven members based on their lithofacies and some kind of microfossil occurrences.Concerned to nannofossil biostratigraphy, three nannofossil events were detected in the sequence and they were the last occurrence (LO) of Pseudoemiliania lacunosa (Kamptner) Gartner, the first appearance (FA) of Emiliania huxleyi (Lohmann) Hay and Mohler and the start of acme stage (s.a.) of Emiliania huxleyi in ascending order. In the transoceanic correlation, LO of Pseudoemiliania lacunosa is estimated at 440 ka, FA of Emiliania huxleyi 270 ka and s.a. of Emiliania huxleyi 70 ka (Gartner, 1977).On the other hand six conspicuous marker tephra are defined in the Kuhko-shima Formation based on volcanic glass major chemical composition analyzed with an energy dispersive microspectrometry (EDS). They are Hatchoike, Sakura, Sugawara, V-7, AT and Ah in ascending order. These tephra are found as a volcanic glass-rich layers and spread widely in the core samples in and around the Osaka Bay. Hatchoike is in Ma5 and Sakura is in the lower part of Ma7 clay beds of the group. Both tephra are reliable markers in the Upper Formation of the group which were defined in land sequence of Kinki. The fall ages of Hatcho-ike and Sakura are estimated at ca. 500 ka and 400 ka respectively. Machida and Arai (1992) correlated V-7 to Ata which ejected in 90-110 ka from Ata caldera of southern Kyushu. Aira (AT) and Akahoya (Ah) are reported by many authors and their fall age are estimated at 24 ka and 6.3 ka respectively.In the present area, following nannofossil events and tephra falls are listed in ascending order : LO of Pseudoemiliania lacunosa, falls of V-15, Sakura, V-14, V-10, Sugawara, V-8, FA of Emiliania huxleyi, s.a. of Emiliania huxleyi, falls of AT and Ah. In general age estimation of these events are correspond with international correlation and established tephrostratigraphy in Japan.

Opening Address for the Symposium “High-Resolution Dating for Quaternary Research”

This symposium aims to give overview and prospect for the high-resolution age determinations for Quaternary research. In order to understand global environmental changes of the past, or to predict the changes expected in the near future, one would like to know a detailed history of environmental changes through the high-resolution dating. The papers presented in the symposium are to be divided into two categories: 1) non-radiometric age determination for the recent past such as chronology of tree ring, archaeological evidence, ice-core and laminated lake sediments, and palaeontological chronology. 2) radiometric age determinations including AMS radiocarbon dating, wiggle matching, calibration of radiocarbon dating, U series, TL, ESR, FT and K-Ar dating methods.The most important subject currently discussed is to give the high-resolution age for the datum planes that are commonly used in the Quaternary research. Of them, the problem of the Younger Dryas age arises a very interesting and valuable chance for improving up the dating technique of such methods as dendrochronology, ice-core chronology, varve chronology, radiocarbon method, etc. Recent advances in orbital time scale have given high-resolution age controls for both climatically induced marine isotope and geomagnetism, resulting in a stimulation of high-resolution radiometric age determinations.

Magnetostratigraphy of the Middle Jurassic Brent Group in the Oseberg oil field, northern North Sea

Magnetopolarity stratigraphy of the Brent Group and the uppermost part of the Dunlin Group has been established in two well cores from the Oseberg Field (well 30/6 - 7 and well 30/9-2), northern North Sea. Palaeomagnetic analysis of thermal demagnetization results defines a series of normal and reverse magnetozones in both wells. Remanent coercivity analysis of these Middle Jurassic clastic sediments indicates a magnetomineralogy independent of grain size interpreted to be of diagenetic origin, thus suggesting that the magnetization is of early post-depositional origin. Integration with the existing palynostratigraphic framework results in the establishment of several isochronous horizons, especially in the Ness Formation, which suggests lateral continuity of magnetostratigraphic datum planes between the two wells at the Oseberg Field. Although the exact dating of the magnetozones is not established, the combined application of magnetopolarity and biostratigraphy provides a stratigraphic framework of improved resolution for these rock formations.

Orbital cyclicities above and below the Cretaceous/Paleogene boundary at Zumaya (N Spain), Agost and Relleu (SE Spain)

The rhythmicity of hemipelagic limestone/marl successions covering the Cretaceous/Paleogene (K/Pg) boundary, is investigated and evidence of orbital control is presented. Three sections were surveyed and sampled in detail: two are located near Agost and Relleu in the province of Alicante, and one near Zumaya in the Basque country. The distance between Agost and Relleu is about 30 km, between Agost and Zumaya about 600 km. The carbonate content of 2779 samples was determined and used as a proxy to determine cyclicities. Lithologically, all three successions are very similar, although in the Maastrichtian of the Zumaya succession (63.7 m) 339 light-green siliciclastic turbidite layers, varying in thickness between 0.1 and 12 cm, intercalate with the calcisiltites. Conventional paleomagnetic and micropaleontologic datum planes are few and show the usual associated uncertainties. Power spectra based on the few reliable datum planes available are unstable. More datum planes were created in an unconventional way, i.e. by visual correlation of the local maxima and minima of the carbonate curves to those of the relevant part of the theoretical eccentricity curve. The validity of the method is based on the assumption that the eccentricity periods are considered practically stable throughout geologic time. The results support the hypothesis that the carbonate rhythmicity at Agost, Relleu and Zumaya, are orbitally controlled. Most likely, orbital forcing and random processes play a role in the frequency of occurrence and the thickness of turbidites in the Maastrichtian of Zumaya. The age of the K/Pg boundary is estimated at −64.56 ± 0.4 Ma.

High‐resolution correlations between Gotland and Estonia near the base of the Wenlock

The strata of the Ireviken Event can be correlated between Gotland, Sweden and the Viki core on Saaremaa, Estonia, with a high degree of precision. Most of the ten datum planes are found with a precision of better than 0.1 m in the Lower and upper Visby Beds on Gotland and high in the Mustjala Member of the Jaani Formation on Saaremaa. Five of the latest Llandovery–early Wenlock units defined by these datum planes are between c. 0.12 and 1.77 m thick on Gotland and 0.12 and 0.67 m in Estonia. The duration of each was between a few thousand and c. 31 000 years. The stratigraphic resolution achieved in the interval of the Ireviken Event is 10,000 years. Ultimate range ends are lacking within a preceding, slightly longer interval, but the pattern of intermittent presence of some taxa agrees well with an unchanged relative rate of sedimentation. Their coeval presence in different places indicates ecological, regional or more widespread changes.

Controversies on the Placement of Cretaceous-Paleogene Boundary and the K/P Mass Extinction of Planktonic Foraminifera

Examination of recently reported K/P boundary sections indicates that the placement of the K/P boundary is based on equivocal criteria and that the boundary as placed is not synchronous. The conclusion that the K/P boundary in several U.S. Gulf Coast sections is complete and within a condensed section is simply the artifact of delineating the K/P boundary on disparate paleontologic datum planes and preservational bias of the microfossil assemblages. The upper slope and outer shelf sections at El Kef, Gredero, and Agost as well as the DSDP Site 577 section are continuous. The non-separation of Zone P0 at some deep sea sites is due to very low sedimentation rates and the short time interval of Zone P0