Belt Settings Research Articles

Evaluating the quality of bed length and area balance in 2D structural restorations

The use of structural restorations as a tool to investigate structural evolution, fault and horizon relationships, and validity of interpretation has been widespread for more than four decades. The first efforts relied on hand-drafted bed-length measurements of commonly constant thickness stratigraphic units and were typically applied to fold-and-thrust belt settings. The advent of computer-assisted section construction and restoration software allowed for the assessment of more complicated structural interpretations by applying several new methods for forward and inverse strain transformation. Although quicker and more accurate than hand-drafted, the results of computer-aided structural modeling still need to be interrogated. We have reviewed the different strain transformation (restoration) methods available and their implications for bed length and area conservation: (1) fundamental simple shear and its two basic modes (flexural slip and inclined shear inversions), (2) fault-related folding techniques, and (3) the effects of mechanical stratigraphy and compaction. The assessment of the restoration methods was illustrated by examining two examples: the Mount Crandell Duplex Structure in southern Alberta and the Virgin River Extensional Basin in the southeast of Nevada. For both examples, we developed tables listing and confirming the deformed/restored state line lengths and areas. We believe that such tables should be provided for any strain transformation exercise, along with the restoration results as parameters for quality control, to prevent over- and underestimations that deviate more than 5% from the initial interpretation.

When was the Earth’s conveyor belt set in motion?

The start of plate tectonics on Earth is one of the most controversial issues in modern geology, with proposed timings covering almost the entire history of our planet. On page 2387 of this issue (vol. 100, 2015), Blichert-Toft and co-authors report Sm-Nd and Lu-Hf isotopic and lithophile trace element data for early Archean komatiites from the Barberton Greenstone Belt (GB) in South Africa, and argue for the onset of plate tectonics on Earth as early as 3.5 Ga. The studied komatiites show a large decoupling of the two isotopic systems and lithophile trace element signatures that are most consistent with deep-water, pelagic sediments being present in the lower-mantle source of these lavas. Their conclusions have far-reaching implications for advancing our understanding of how the Earth system operated in the distant geological past.

Matrix deformation in a basement-involved fold-and-thrust-belt: A case study in the central Andes, Malargüe (Argentina)

An analysis of the anisotropy of magnetic susceptibility (AMS) is used to investigate the matrix strain record of weakly deformed clastic rocks, including sandstones and shales, along a cross-section of the Malargüe fold-and-thrust belt (MFTB, Argentina). We collected 339 oriented cores from the Tres Esquinas Sandstones, the red beds of the Tordillo and Neuquén formations, as well as from Shales/Silts of the Mendoza Group. Overall, ~90% of the magnetic fabrics are well defined and are related to the strain imprint of the layer parallel shortening. Among the tectonic-related fabrics, 40% show the development of a magnetic lineation at right angle of the shortening (type II), 38% display an apparent loss of magnetic foliation (type III) and 21% develops a magnetic foliation at right angle of the shortening (type IV). There is no lithological control on magnetic fabric typology despite contrasting ferromagnetic mineralogy between the red sandstones and dark shales. Thin-section observations highlight the good match between the orientation of both the susceptibility ellipsoid and microstructure orientation, which enables us to infer the preferred orientations of the petrofabric (i.e. finite strain directions). In this way, two trends can be recognized in the study area: shortening directions trending N110 in the north and trending N80 in the south. In addition, the spatial distribution of magnetic fabric typology and burial data suggests an atypical pattern of deformation from the foreland to hinterland. Such a pattern contrasts with previous studies in fold thrust belt settings, suggesting that, at the matrix-scale, the deformation (even in a pre-folding setting) is compartmentalized and controlled by the occurrence of deep-seated thrusts localized along inherited structures. From the analysis of cross-sections, we can distinguish several domains, each of them reflecting distinct states of matrix deformation.

The long-term high-temperature history of the central Namaqua Metamorphic Complex: Evidence for a Mesoproterozoic continental back-arc in southern Africa

Reaction textures, equilibrium assemblage modelling and in situ U–Th–total Pb monazite and zircon U–Pb LA-ICP-MS dating of metapelitic rocks provide new insights to the tectono-metamorphic evolution of the Kakamas Terrane in the central Namaqua Metamorphic Complex (NMC). Staurolite inclusions in garnet porphyroblasts and patchy sillimanite intergrowths probably after kyanite record an amphibolite facies prograde stage of the Mesoproterozoic Kibran/Namaquan orogeny. The peak assemblages in metapelites are (i) osumilite, replaced by alkali feldspar+cordierite+orthopyroxene+quartz±plagioclase, (ii) spinel+quartz and (iii) corundum+quartz in the southwest of the study area and (iv) garnet+cordierite+quartz+sillimanite±alkali feldspar±plagioclase±biotite parageneses in the northeast. The spinel+quartz bearing metapelites in the highest-grade domains in the southwest of the study area equilibrated at 800–900°C at ∼5.0kbar. Osumilite may have formed at somewhat higher temperatures in excess of 900°C. In shallower crustal levels, exposed in the northeast of the study area, the metamorphism reached 640–680°C at 4.0–4.5kbar, followed by minor decompression to 3.5kbar. Isobaric cooling during retrogression in the highest-grade rocks forms biotite+sillimanite+quartz intergrowths replacing Fe–Mg peak and post-peak phases at 650–700°C. Minor re-heating overprints these textures forming a new garnet generation. P–T conditions lower than the middle/upper amphibolite facies conditions are not recorded in the study area.Two generations of zircon showing oscillatoric zonation document an early Kibaran stage of anatexis in metapelites at 1351–1299Ma, followed by a more commonly seen younger stage of partial melting at ∼1200Ma. The UHT peak metamorphism is either associated with the first anatexis at ≥1300Ma or, more likely, is an early stage of the widespread partial melting in the NMC at ∼1200Ma. The monazite data set shows, in addition to ∼1200Ma ages, two further age populations. The first of these, dated as 1090±9–1071±6Ma, is associated with the second garnet growth. Younger monazite rims, formed at ∼1000Ma in lower grade rocks, are not related to other mineral reactions or textures and are interpreted as forming in relation to late-orogenic fluid influx.The long-lasting high-temperature history (>650°C) between ∼1350 and <1100Ma, locally reaching UHT-conditions, with slow cooling and heating episodes at near-constant mid-crustal pressures is not well compatible with crustal thickening and continent-collision models that have been proposed in the existing literature. We interpret the Mesoproterozoic evolution of the high-temperature crust in the central NMC as related to long-lasting, steady heat transfer from the mantle into a thinned lithosphere in a continental back-arc mobile belt setting, reaching higher granulite facies and in places UHT conditions during the Mesoproterozoic Kibaran/Namaquan orogeny.

Influence of thrust belt geometry and shortening rate on thermochronometer cooling ages: Insights from thermokinematic and erosion modeling of the Bhutan Himalaya

Advancements in thermochronology and numerical modeling offer the potential to associate the age of thermochronometric samples to both exhumational and deformational processes. However, understanding how these components are related in compressional systems requires linking the geometry and magnitude of fault slip to the distribution and amount of erosion. To address this, we apply a 2-D thermokinematic model to a forward modeled balanced cross section to quantify the cooling history in fold-thrust belt settings. The restored cross section provides a kinematic path of rocks and structures necessary to reproduce the surface geology. By assigning ages to displacement amounts, we produced a range of potential velocity vectors used to calculate heat transport, erosion, and rock cooling. We test the predicted ages against a suite of previously published thermochronometric data from the Bhutan Himalaya to explore the utility of the data to constrain the timing, rate, and geometry of fault motion as well as variations in the exhumation rate. We evaluate the cooling history associated with a constant rate of shortening of 18 mm/yr, rates that are 2.0, 1.5, 0.75, and 0.5 times the constant rate, and rates that vary with time to determine which kinematic history best matches the measured cooling ages. The combination of relatively old apatite fission track and zircon (U-Th)/He measured ages and younger (15–9 Ma) 40Ar/39Ar ages from white mica is best matched with faster rates (relative to constant rates) between 11.5 and 8 Ma and slower than constant rates from 17 to 11.5 Ma and 8 Ma to present.

Some Evidence of South European Contacts of the Middle Volga and Kama in the Material Culture of Toretskoe Urban Settlement

The relevance of the article is determined by insufficient study of the late Middle Ages material culture in the Volga-Kama region and its inclusiveness in Eurasia’s culture development. The purpose of this article is to present a whole attribution and historical interpretation of the belt set and an accessories element or a detail of a musical instrument. A complex approach, consisting of comparative-typological and historical-geographical methods is used in the work. The alloy’s nature of the non-ferrous metal ware has been identified by a scanning electronic microscope/ X-ray diffraction. The material under consideration reveals a wide geography of similarities within Eurasia that in many cases is caused by the process of intercultural interaction in the late Middle Ages. The study presents technological characteristics of the ware, their origin and possible ways of entering the Volga-Kama region have been determined and the dating has been specified. This article should be of interest to archaeologists and historians of international relations and the late Middle Ages material culture during their research and educational process.

Alloy Composition in the Prestigious Silver Ware of the Old Turkic Period of Southern Siberia

A series of silver artifacts (ornaments, belt sets, horse equipment, and utensils) belonging to the most dynamically developing categories of the material culture of the Old Turkic period were examined using X-ray spectral analysis. The study of silver alloy compositions of various prestigious objects from representative archaeological complexes of southern Siberia (Kudyrge, Tuekta, Katanda, Bertek-34, Yustyd, and Ur-Bedary) made it possible to single out their main territorial groups: Altai, Kuznetsk, and Middle Yenisei. Four main kinds of silver alloys were identified: Ag-Cu, Ag-Cu-Su, Ag-Cu-Pb-Su, Ag-Cu-Zn. The highest silver content was found in the Old Turkic vessels of the first group. The belt decoration items and horse equipment parts demonstrate a variable alloy composition, mirroring cultural contacts between southwestern Siberian groups and those living in the adjacent regions in the second half of the 1st millennium AD.

Constraining South Atlantic growth with seafloor spreading data

Recent models of South Atlantic opening history focus on early plate divergence by incorporating intracontinental deformation, which is poorly constrained. Aiming to avoid the uncertainties in this approach, we model the entire divergence history with a joint inversion for seafloor spreading data. For this history, the pre-Campanian motion parameters are the first to feature formal uncertainty estimates. We date the onset of spreading at 138 Ma, with movement along intracontinental accommodation zones leading to the assembly of South America by 123 Ma and Africa by 106 Ma. Part of the ridge in the Agulhas Basin jumped westward soon afterward toward the Bouvet plume, initiating the motion of a short-lived Malvinas Plate. The NE Georgia and Maud rises and Agulhas Plateau formed as a large igneous province over the plume. Farther north, part of the ridge jumped eastward toward the Tristan plume around 94–93 Ma but seems not to have resulted in independent plate motion. Our results show that the South Atlantic grew by diachronous breakup of continents on just two plates. Cretaceous intracontinental deformation in South America and Africa can be interpreted in terms of the accommodation of stress associated with northward propagation of this process. The pattern of accommodation is usually envisaged as focusing all of the strain in narrow belts. With our rotations, a commonly used set of such belts accounts instead for just 42–67% of the implied total strain. We suggest that the remainder was accommodated at all scales within the continental interiors and the extended continental margins.

New Belt of the “Byzantine Circle” from the Medieval Bayanovsky Burial Ground in the Perm Territory

A precious belt of the “Byzantine circle,” belonging to a representative of the local social elite was discovered in a burial of the 10th century at the Bayanovsky burial ground (Perm Territory). The belt is dated to the mid-8th century. Individual elements of similar belts have been found relatively often over large areas, including the Perm Territory, however, complete belt sets are rare. The belt shows extensive parallels with Avar and Khazar antiquities, but is distinguished by its unique decor, including the themes of the “royal” feast and lovemaking. The length of time between the production of the belt and its placement in the burial poses some questions.

Detrital thermochronologic record of burial heating and sediment recycling in the Magallanes foreland basin, Patagonian Andes

AbstractThe Patagonian Magallanes retroarc foreland basin affords an excellent case study of sediment burial recycling within a thrust belt setting. We report combined detrital zircon U–Pb geochronology and (U–Th)/He thermochronology data and thermal modelling results that confirm delivery of both rapidly cooled, first‐cycle volcanogenic sediments from the Patagonian magmatic arc and recycled sediment from deeply buried and exhumed Cretaceous foredeep strata to the Cenozoic depocentre of the Patagonian Magallanes basin. We have quantified the magnitude of Eocene heating with thermal models that simultaneously forward model detrital zircon (U–Th)/He dates for best‐fit thermal histories. Our results indicate that 54–45 Ma burial of the Maastrichtian Dorotea Formation produced 164–180 °C conditions and heating to within the zircon He partial retention zone. Such deep burial is unusual for Andean foreland basins and may have resulted from combined effects of high basal heat flow and high sediment accumulation within a rapidly subsiding foredeep that was floored by basement weakened by previous Late Jurassic rifting. In this interpretation, Cenozoic thrust‐related deformation deeply eroded the Dorotea Formation fromca. 5 km burial depths and may be responsible for the development of a basin‐wide Palaeogene unconformity. Results from the Cenozoic Río Turbio and Santa Cruz formations confirm that they contain both Cenozoic first‐cycle zircon from the Patagonian magmatic arc and highly outgassed zircon recycled from older basin strata that experienced burial histories similar to those of the Dorotea Formation.

A Late Roman Military Burial from the Dyke Hills, Dorchester on Thames, Oxfordshire

AbstractDamage to part of the earthwork at Dyke Hills, Dorchester on Thames, provided the opportunity to recover the badly disturbed remains of a late Roman burial which had contained an elaborate belt set and an axe. This burial, of a type very unusual in Roman Britain, is argued to be of early fifth-century date and to be directly comparable with well-known burials recovered near by in 1874 which formed a starting point for the ‘soldiers and settlers’ debates of the 1960s and beyond. The Dorchester burials are seen here as those of late Roman military personnel, and their local and wider context is discussed.

Kurgans of the Yenisei Kyrgyz at the Chineta II Burial Ground in the Altai

This study focuses on the results of excavations of the Kyrgyz burial mounds at Chineta II, northwestern Altai. Local burials in this region are cremations accompanied by weapons, belt sets, and horse harness. They represent two stages of the local variant of the Kyrgyz culture – Yakonur (late 9th – early 10th centuries) and Ak-Tash (late 10th – 11th centuries). The findings demonstrate contact between the Kyrgyz immigrants and the Altai natives. At the Yakonur stage, they appeared to have coexisted peacefully, given that in the 9th–10th centuries Turks were allies of the Kyrgyz in their wars against the Uighurs. At the late stage, the nature of relationships changed, as evidenced by an intrusive Kyrgyz burial in a Srostki kurgan. This may be due to either hostility or to loss of knowledge about the ethnic attribution of the mound. If the latter is true, the Kyrgyz settlement of the Altai in the 11th century was not permanent.

Материалы сяньбийского времени погребаль-но-поминального комплекса Тыткескень-VI на Алтае

The article is devoted to the publication of the archaeological materials of the Bulan-Koby culture that was obtained during the field research of burial ground in Tytkesken-VI. There are six burial mounds and one layout which were discovered at this cemetery in the 1989. Also there were found individual items in the 1990, perhaps they have ritual purposes in the past, which were fixed in terrestrial constructions. The authors have carried out a comparative analysis of real sources, according to the given current state of knowledge on the archaeology of the Altai at the Xianbei-Zhuzhan Time as well as recent changes were adjusted to the periodization of archaeological cultures of nomads in North and Central Asia, at the II BC – the V century AD. The study focuses on the chronological attribution of weapons, buckles and belt set. Correlation of artifacts relating to the accompanying inventory led to the conclusion that the study refers to a group of burials Xianbei Time and can be dated at the end of II – in beginning of the III century AD. Artifacts from burial ground conventionally which called ritual objects №50 and №53 can be related with so called Belyj-Bom`s period of the Bulan-Koby culture (the II – the 1st half of the IV century AD). The aggregate of archaeological data has confirmed the relevance with the study on the chronology of the obsequies complexes from Altai region at the epoch of the Great Migration of peoples.

On-line versus off-line NIRS analysis of intact olives

Visible/near-infrared calibrations were developed for the determination of the quality parameters (fat content, moisture and free acidity) of intact olive fruits. The reflectance spectra were acquired in two different instruments (diode-array versus grating monochromator based instruments). The grating monochromator based instrument was used at the laboratory (off-line analysis), whereas the portable diode-array based device was placed on top of a conveyor belt set to simulate measurements in an olive oil mill plant (on-line analysis). Partial least squares (PLS) regression and least squares support vector machine (LS-SVM) were used for the development of the calibration models. A total of 174 samples were prepared for the calibration (N = 122) and validation (N = 52) sets. The root mean square error of prediction (RMSEP) and the residual predictive deviation (RPD) values were better using the diode-array instrument and applying the PLS regression method for the fat content parameter while for the free acidity and moisture content, the LS-SVM algorithm gave the best results. The results obtained seems to suggest the viability of the on-line system, instead of the off-line analysis, for the determination of physicochemical composition in intact olives.

Solutions to Non-Conforming Fire Compartment of an Exhibition Hall

Abstract With the rapid development of our economy and the prosperity of the market economy, large exhibition buildings have been built numerously. Because of their special functional requirements, the exhibition buildings are commonly facing the problem of over large scale areas, and the problem that fire zone division rarely meet the requirements of relevant national fire protection technical standards. At the same time, this kind of building always presents hazards of crowded people and high volume of combustible content, where fire would spread rapidly, evacuation and fire suppression are difficult to carry out, leading to severe property loss. In this paper, the problem of the fire partition of an exhibition hall is resolved by comprehensive use of fire belt set in exhibition hall and other supplementary fire fighting measures to solve.

Did They Exist? The Question of Elites in Western Lithuania in the Roman and Early Migration Periods, and Their Interregional Contacts

The emergence of Iron Age elites in the Baltic lands is discussed here in the context of western Lithuania, a region with local amber deposits and distant interregional connections, with reference to what is called the West Lithuanian Group, with cemeteries with stone circles. No interregional status symbols have been recorded in the area, but it is possible to identify local prestige goods, such as equestrian equipment, horse offerings, drinking horns and decorative belt sets (male indicators), and elaborate headdresses and necklaces, and splendid pectoral ornaments (female indicators). Precious imports and silver or silver-plated* ornaments are to be found in both male and female graves. The inhabitants of western Lithuania in the Roman and Early Migration periods differed according to their social status. It is possible to distinguish quite a large number of well-equipped graves, but no exceptionally rich ones. Local elites existed in certain small territorial communities, but there were no regional elites. The destroyed grave 31 at Baitai may be an exception to this rule: it presents a sign of the appearance of people of very high rank, a process which developed further in later periods.

High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda–Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite–martite–goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in ‘least-altered’ hematite–magnetite–metachert–BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe–Ca–Mg–Ni–Co–P–REE metasomatism that produced local Ni–REE-rich Fe–dolomite–magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle–ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni–Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite–hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)–Fe–dolomite–quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides, carbonate and quartz to form veins and breccia but did not generate significant volumes of iron ore. Ore stage 4 involved Mesozoic(?) to recent supergene oxidation and hydration in a weathering environment reaching down to depths of ∼100 to maximum 200 m below surface. Supergene ore formation involved goethite replacement of dolomite and quartz as well as martitisation. Important ‘ground preparation’ for supergene modification and upgrade were mainly the formation of steep D1 to D4 structures, steep BIF/basalt margins and particularly the syn-D1 to syn-D2 carbonate alteration of BIF that is most susceptible to supergene dissolution. The Windarling deposits are structurally controlled, supergene-modified hydrothermal iron ore systems that share comparable physical, chemical and ore-forming characteristics to other iron ore deposits in the Yilgarn Craton (e.g. Koolyanobbing, Beebyn in the Weld Range, Mt. Gibson). However, the remarkable variety in pre-, syn- and post-deformational ore textures (relative to D1 and D2) has not been described elsewhere in the Yilgarn and are similar to the ore deposits in high-strain zones, such as of Brazil (Quadrilatero Ferrifero or Iron Quadrangle) and Nigeria. The overall similarity of alteration stages, i.e. the sequence of hydrothermal carbonate introduction and hypogene leaching, with other greenstone belt-hosted iron ore deposits supports the interpretation that syn-orogenic BIF alteration and upgrade was crucial in the formation of hypogene–supergene iron ore deposits in the Yilgarn Craton and possibly in other Archean/Paleoproterozoic greenstone belt settings worldwide.

Identifying the Criteria for Determining Status Burials by Results of Integrated Analysis

ABSTRACTChemical-technology investigation was carried out for 95 belt sets from the burials of 8th−11thcenturies. In its course three groups of burials were separated on the basis of archaeology-statistical features; the Group 3 was identified as status one. All the groups contain belt sets made from the cooper-based alloys which include silver (6.98−92.87%) and amalgam. The major scheme of the belt sets (Groups 1, 2, 3) production is casting in moulds with print of used plaques; there are belt sets in Groups 1 and 2 which were made in different way (lost wax casting, casting in moulds with print of special matrix, forging). Chemical and technology parameters of the belt sets from the elite burials of the Group 3 are similar to the parameters of the belt sets discovered in the common burials of the Groups 1 and 2. There are a number of burials in the Group 1 the belt sets of which according to their chemical-technology characteristics could be attributing to the “award”.

Subsalt Depth Seismic Imaging and Structural Interpretation in Dumre Area, Albania

The challenge of seismic exploration in fold and thrust belt settings is to optimize the depth seismic images of the deep structural objectives beneath a complex overburden that may show strong horizontal and vertical velocity variations. In such areas, the seismic image is frequently of poor quality and the depth models of deep layers is often false due to the perturbed propagation of seismic energy through the deforming lens of the overlying layers. A range of seismic processing tools, including post-stack and pre-stack depth migrations, are appropriate to predict the accurate geometry of deep target structures and to improve the building of a depth structural model.A strong combination of geological reasoning and depth seismic imaging processing can improve the understanding of the deep geological structures by reducing the uncertainties in depth geometrical and velocity model estimation. We propose an interpretative and iterative approach to the post stack depth migration method to guide the interpreter in the development of a reliable subsurface model. We have applied this approach during an exploration study in the Dumre area, located in the Ionian Basin (Albania) which is a complex fold and thrust belt. The main objectives of this study were to understand the failure of a former exploration well and to propose a new location for the potential closure of the carbonate structure. This subsalt imaging study aims at illustrating the improvements obtained by application of this integrated seismic imaging method especially in the evaluation of a subthrust prospect in a tectonically complex belt setting.

A Unique Find of a Belt Set from Viminacium

A Unique Find of a Belt Set from Viminacium