Fold Test Research Articles

Substitusi Tepung Daging Buah Lindur terhadap Tingkat Kesukaan Bakso Lele

Catfish (Clarias gariepinus) in addition to containing essential nutrients such as protein also contain essential amino acids. If compared with red meat such as beef and chicken,nutritional content catfish more healthy because of high protein also low in fat and cholesterol. To reduce the price of high import tapioca, lindur flesh can be used as flour for one alternative in tapioca starch ingredients in fishballs. Lindur fruit is one typeof mangrove that is very potential as a new food source because of its high protein and carbohydrate content. The purpose of this research was determine the number of substitution of the best lindur flour to the level of preference catfishballs. This research was conducted in May 2017. Located at the Fishery Product Laboratory Faculty of Fisheries and Marine Science Padjadjaran University and Proximate Test was conducted at the Food Technology Laboratory Faculty of Technique Pasundan University. The method used was experimental, with 20 semi-trained panelists with five treatments substitution of tapioca and lindur flour which are 0%:100%, 12.5%:87.5%, 25%:75%, 37.5%:62.5%, and 50%:50% lindur flour with tapioca. The parameters observed were test for protein content, carbohydrate content, water content, ash content, lipid content, tannin content, elasticity, and preference level. Proximate data were analyzed descriptively based on SNI 01-3819-1995 on fish meatballs quality. Based on the result catfish meatballs research test concluded that the best preference catfish meatballs that is with the addition of lindur flour of 12.5% with the average value based on the criteria of the preferred organoleptic characteristics of the appearance 7.8, aroma 7.8, texture 7.5, taste 7.9 and had an alternative value of 8.00. The average folding test score is 5, very chewy. Result of proximate analysis showed carbohydrate result of 22.70%, protein of 14.56%, lipid content of 9.97%, ash content of 2.71%, water content of 48.93%, tannin of 6.54 ppm

Physicochemical Properties of Duck Feet Collagen with Different Soaking Time and Its Application in Surimi

Duck feet are considered as waste products because people normally do not consume duck feet. It is highly available in Malaysia and thus has the high potential to be the alternative source to produce collagen other than fish, bovine or porcine. The main objective of this study is to evaluate the physicochemical properties of different treated duck feet collagen and its effect on the quality of sardine surimi. Duck feet was stirred and soaked in 5% lactic acid solution for different time (12, 24, 36 and 48 h) at 4oC. Another treatment for the duck feet is demineralization. Duck feet collagen was demineralized by 0.5M EDTA solution for 24 h prior soaking in lactic acid solution for 24 h. Soaking time 24, 36 and 48 h has successfully decreased fat content of duck feet collagen significantly compared to 12 h. However, no differences in yield were observed for the samples. Prolong soaking time produced duck feet collagen with higher content of imino acid (hydroxyproline + proline). The intensity of lightness (L*) for the demineralized duck feet collagen is lower compared to duck feet collagen which was not treated by EDTA. Duck feet collagen has the ability to improve the quality of sardine surimi gel by enhancing its lightness, water holding capacity, gel strength and texture with low cooking loss and expressible moisture. The folding test score of sardine surimi gel has been increased from 3.00 to 5.00 by the addition of duck feet collagen. The gel strength for sardine surimi gel with the addition of duck feet collagen is in the range of 2625.90 g.mm to 2681.58 g.mm, which is approximately 9 times higher than the gel strength of sardine surimi without collagen (280.43 g.mm).

First Early Permian Paleomagnetic Pole for the Yili Block and its Implications for Late Paleozoic Postorogenic Kinematic Evolution of the SW Central Asian Orogenic Belt

AbstractWe conducted a paleomagnetic study on the Early Permian volcanic and sedimentary rocks, and the Neoproterozoic mafic dikes in the Yili Block, NW China. Magnetite and hematite were proven to be the principal magnetic remanence carriers. Demagnetizations revealed stable characteristic remanence magnetizations with a sole reversed magnetic polarity. The magnetic remanence of only the Early Permian strata turned out to be primary based on positive fold tests; meanwhile, the magnetic remanence age of the mafic dikes is ambiguous. Accordingly, the first Early Permian paleomagnetic pole for the Yili Block is calculated at λ = 81.5°N, φ = 256.5°E, N = 11, and A95 = 10.9°. Comparisons of this new pole with published ones from the Yili, Tarim, and South Junggar blocks provide new quantitative constraints on late Paleozoic kinematic evolution of the SW Central Asian Orogenic Belt: (1) Between the Yili and Tarim blocks, significant relative movement took place along major strike‐slip faults during the Late Carboniferous to Early Permian (580 ± 290 km) and the Early to Late Permian (585 ± 340 km), and the displacement rate increased from the Late Carboniferous to Early Permian (~19.3 ± 9.7 mm/yr) to the Early to Late Permian (~29.3 ± 17.0 mm/yr); (2) a significant relative rotation of 28.3° ± 18.3° in the Late Permian, and a lateral displacement of 630 ± 295 km after the Late Permian occurred between the Yili and South Junggar blocks. The significant strike‐slip movements played an important role in the formation of the Central Asian Orogenic Belt and should be considered with great attention in tectonic and paleogeographic reconstructions.

Experimental and numerical study of the mechanical behavior and kinetics of the martensitic transformation in 304L TRIP steel: applied to folding

In this paper, experimental and phenomenological modeling of the mechanical behavior and austenite-martensitic transformation after deformation in 304L TRIP steel is investigated. Mechanical behavior and the evolution of the microstructure after folding test were studied 25 °C. Scanning electron microscopy (SEM), Vickers hardness measurements, and X-ray diffraction test were conducted in order to characterize the deformation response and microstructure evolution of 304L TRIP steel. The analysis results indicate that both the microstructure and mechanical properties of the 304L TRIP steel varied gradually during the tests, the later showed too that the most favorable way for the formation of martensite is tension. Secondly, a phenomenological constitutive model, developed by Iwamoto et al., was selected and modified to include the microstructure evolution (austenite to martensite) after deformation. The validity and the limitation of the simulations are checked against the experimentally established stress–strain relation and the evolution of martensite phase. The simulation results show that the volume fraction of martensite is proportional to the strain and it is very important in the tended zone than the compressed zone. The results above present a foundation for the folding control technology.

Laser-Induced Molybdenum Carbide-Graphene Composites for 3D Foldable Paper Electronics.

Versatile and low-cost manufacturing processes/materials are essential for the development of paper electronics. Here, a direct-write laser patterning process is developed to make conductive molybdenum carbide-graphene (MCG) composites directly on paper substrates. The hierarchically porous MCG structures are converted from fibrous paper soaked with the gelatin-mediated inks containing molybdenum ions. The resulting Mo3 C2 and graphene composites are mechanically stable and electrochemically active for various potential applications, such as electrochemical ion detectors and gas sensors, energy harvesters, and supercapacitors. Experimentally, the electrical conductivity of the composite is resilient to mechanical deformation with less than 5% degradation after 750 cycles of 180° repeated folding tests. As such, the direct laser conversion of MCGs on papers can be applicable for paper-based electronics, including the 3D origami folding structures.

Effects of Sodium Hydroxyethyl Sulfonate on Improving the Ductility of the Copper Films Deposited by Electroless Plating from High‐Speed Plating Baths

AbstractThe copper films that electroless plated from the formaldehyde‐based solutions frequently suffer from the internal stress. The internal stress leads to a poor ductility of the plated films. To lower internal stress and improve ductility of copper films, sodium hydroxyethyl sulfonate was used as a surfactant to promote the detachment of hydrogen bubbles. The folding tests showed that the copper film deposited from the solution containing 3 mL L−1 25% sodium hydroxyethyl sulfonate (EHS) had the best ductility. The internal stresses of the copper films were measured using X‐ray diffraction technique and the stress decreased from 100 MPa to 30 MPa as the EHS concentration increased from 0 to 3 mL L−1. Sodium hydroxyethyl sulfonate had little influence on the film morphology and crystal size. High plating rates (> 8 μm h−1) were obtained from the solution containing sodium hydroxyethyl sulfonate.

Remagnetization of the Lower Ordovician Hongshiya Formation of the southwestern Yangtze Block

Large-scale block migration has been proposed based on Early and early Late Ordovician paleomagnetic data for the South China Block (SCB). However, this is anomalous in terms of the previously reconstructed affinity between the SCB and East Gondwana. A paleomagnetic and petrographic reassessment of the Lower Ordovician sedimentary rocks is therefore necessary to assess the reliability of the Early Ordovician paleopole of the SCB. Consequently, we obtained paleomagnetic data from 47 sites at five localities of the SCB. For most specimens, detailed thermal demagnetization experiments yielded viscous components at ~120 °C, while the stable characteristic remanent magnetization (ChRM) was isolated up to 680 °C. The ChRM passed the fold test and hematite is identified as the remanence carrier. The samples give the site-mean ChRM direction Ds/Is = 313.0°/61.9° (ks = 47.1, α95 = 3.2°) after tilt correction (five localities, 47 sites). Although the ChRM direction passed the fold test that was likely acquired before the Tertiary, petrographic studies reveal the occurrence of widespread secondary hematite in the specimens, indicating that the rocks were remagnetized after deposition. The average paleomagnetic direction overlaps with the Jurassic paleomagnetic direction from sampling areas of the southwestern SCB, implying that the remagnetization event occurred during the Jurassic. The Early Ordovician paleopole of the SCB is therefore urgently needed for plate reconstruction of the SCB within Gondwana.

On the nominal transverse shear strain to characterize the severity of creasing

A transverse shear strain was utilized to characterize the severity of creasing for a wide range of tooling configurations. An analytic expression of transverse shear strain, which accounts for tooling geometry, correlated well with relative crease strength and springback as determined from 90° fold tests. The experimental results show a minimum strain (elastic limit) that needs to be exceeded for the relative crease strength to be reduced. The theory predicts a maximum achievable transverse shear strain, which is further limited if the tooling clearance is negative. The elastic limit and maximum strain thus describe the range of interest for effective creasing. In this range, cross direction (CD)-creased samples were more sensitive to creasing than machine direction (MD)-creased samples, but the differences were reduced as the shear strain approached the maximum. The presented development provides the foundation for a quantitative engineering approach to creasing and folding operations.

Paleomagnetic Secular Variation Constraints on the Rapid Eruption of the Emeishan Continental Flood Basalts in Southwestern China and Northern Vietnam

AbstractEstimating the duration of magma eruptions using isotopic dating methods is difficult because of the intrinsic errors of the technique regarding the dated materials (such as zircon). However, the long‐term variation of the geomagnetic field recorded by lava flows can be used to estimate the net duration of an eruption sequence. The Emeishan basalts at Dongchuan, with a thickness of 630 m, yielded a reliable characteristic remanent magnetization of normal polarity and which passed the fold test (Tauxe & Watson, 1994, https://doi.org/10.1016/0012-821X(94)90006-X). Stratigraphic and magnetostratigraphic correlations of the Emeishan basalts in the Dongchuan section with other sections indicate that the eruption of the Emeishan basalts at Dongchuan spans the entire normal polarity zone in the early stage of the Emeishan large igneous province. A flow‐by‐flow analysis of geomagnetic directions of the Emeishan basalts at Dongchuan indicates that four directional groups and fifteen individual lava directions were recorded, with a net duration (excluding quiescent intervals) of no more than 3100 years. The averaged site directions from the Emeishan basalts with normal polarity conforming to a geocentric axial dipole direction indicate that this interval is longer than 104–105 years. In addition, a magnetostratigraphic study indicates that the normal polarity interval recorded by the Emeishan basalts was shorter than 2–20 × 104 years. Thus, the total duration of the normal polarity stage of the Emeishan large igneous province was roughly 105 years. There is a possible relationship between the rapid eruption and the Late Capitanian mass extinction (259.8 ± 0.4 Ma, Henderson et al., 2012).

Palaeomagnetic time and space constraints of the Early Cretaceous Rhenodanubian Flysch zone (Eastern Alps)

The Rhenodanubian Flysch zone (RDF) is a Lower Cretaceous-lower Palaeocene turbidite succession extending for similar to 500 km from the Danube at Vienna to the Rhine Valley (Eastern Alps). It consists of calcareous and siliciclastic turbidite systems deposited in a trench abyssal plain. The age of deposition has been estimated through micropalaeontologic dating. However, palaeomagnetic studies constraining the age and the palaeolatitude of deposition of the RDF are still missing. Here, we present palaeomagnetic data from the Early Cretaceous Tristel and Rehbreingraben Formations of the RDF from two localities in the Bavarian Alps (Rehbrein Creek and Lainbach Valley, southern Germany), and from the stratigraphic equivalent of the Falknis Nappe (Liechtenstein). The quality of the palaeomagnetic signal has been assessed by either fold test (FT) or reversal test (RT). Sediments from the Falknis Nappe are characterized by a pervasive syntectonic magnetic overprint as tested by negative FT, and are thus excluded from the study. The sediments of the Rehbreingraben Formation at Rehbrein Creek, with positive RT, straddle magnetic polarity Chron M0r and the younger M'-1r' reverse event, with an age of similar to 127-123 Ma (late Barremian-early Aptian). At Lainbach Valley, no polarity reversals have been observed, but a positive FT gives confidence on the reliability of the data. The primary palaeomagnetic directions, after correction for inclination shallowing, allow to precisely constrain the depositional palaeolatitude of the Tristel and Rehbreingraben Formations around similar to 28 degrees N. In a palaeogeographic reconstruction of the Alpine Tethys at the Barremian/Aptian boundary, the RDF is located on the western margin of the Brianconnais terrain, which was separated from the European continent by the narrow Valais Ocean.

Paleomagnetic Constraints From the Baoshan Area on the Deformation of the Qiangtang‐Sibumasu Terrane Around the Eastern Himalayan Syntaxis

AbstractThe Sibumasu Block in SE Asia represents the eastward continuation of the Qiangtang Block. Here we report a detailed rock magnetic and paleomagnetic study on the Middle Jurassic and Paleocene rocks from northern Sibumasu, to document the crustal deformation during the India‐Asia collision since the Paleocene and reconstruct the overall strike of the Qiangtang/Sibumasu elements before the India‐Asia collision. Although the fold test is inconclusive based solely on our data, a positive reversal test, a positive regional fold test with previous paleomagnetic results, and a detrital origin of hematite in the red beds as indicated by scanning electron microscopy suggest that the magnetizations obtained from the Jurassic and Paleocene rocks are most likely primary, showing an ~80° clockwise rotation since Paleocene. These results, together with previously published paleomagnetic data, suggest that the northern Sibumasu and northern Simao elements experienced a ~60–80° clockwise rotation since Paleocene. This large clockwise rotation is also consistent with the surface GPS velocity field and NE‐SW fault networks, suggesting a rotational motion of crustal material from southeastern Tibet during late Cenozoic. We infer that the large clockwise rotation is a sum of rotation in the Eocene to Middle Miocene time associated with Indochina extrusion and rotation after the Middle Miocene associated with the E‐W extension in central Tibet. This suggests that the eastward motion of Tibetan crustal material along the Xianshuihe‐Xiaojiang fault after Middle Miocene is transmitted to the southwest toward Myanmar. Jurassic and Cretaceous paleomagnetic results suggest that the Qiangtang/northern Sibumasu was originally a curved structure with an orientation of N60°W in Tibet and changes to N10°W in southern Sibumasu.

Paleomagnetism of a well-dated marine succession in South China: A possible Late Cambrian true polar wander (TPW)

The Cambrian true polar wander (TPW) hypothesis remains controversial largely because of the uncertainties in the quality and/or fidelity of the paleomagnetic data as well as their chronological control. Testing the TPW hypothesis requires high-quality paleomagnetic data of sufficient spatial and temporal resolutions. Here, we present paleomagnetic results of a continuous Cambrian shallow marine succession from South China where available detailed biostratigraphy provides exceptional chronological constraints. Forty-three sites of paleomagnetic samples were collected from this limestone-dominated succession. Stepwise thermal demagnetization generally reveals three-component magnetizations. Low- and intermediate-temperature components can be cleaned by ∼330 °C, and the high-temperature component (HTC) was isolated typically from ∼350 to ∼450 °C. A positive fold test and the presence of reversed polarity in the strata, together with rock magnetic data as well as the scanning electron microscopic (SEM) and transmission electron microscopic (TEM) results, collectively suggest that the HTCs are likely primary. A directional shift of the HTCs occurs between the lower-middle Cambrian and the upper Cambrian strata in the succession and is tentatively interpreted to indicate a ∼57° polar wander from ∼500.5 to 494 Ma. Because the rate of polar wander is too fast to be a tectonic origin, this polar wander is interpreted to represent a Late Cambrian TPW. This TPW appears coeval with the Steptoean positive carbon isotope excursion (SPICE) and the major trilobite mass extinctions, suggesting a potential link between the TPW and the Late Cambrian biotic and climatic changes. Because the proposed TPW event is exceptionally well-dated, it should be testable through examination of other worldwide sections.

Examining Effects of Mathematical Problem-Solving, Mathematical Reasoning and Spatial Abilities on Gifted Students’ Mathematics Achievement

This study examines the relationship between gifted students’ mathematical abilities, spatial abilities, and their mathematics achievement. 293 7th-grade gifted students (%51 male, %49 female) participated in the study. Mathematical reasoning and problem-solving scale were used to determine mathematics abilities of students, mental rotation and paper folding tests were used to determine spatial abilities of students and lastly, mathematics achievement test was used to determine students’ mathematics achievement. Descriptive analysis, as well as Pearson product-moment correlation coefficient and multiple linear regression analysis, were used in the data analysis. The results showed that the mathematics achievement of the students was high, and their mathematical reasoning and problem-solving abilities were above average. There is a high and average significant relationship between gifted students’ mathematical abilities and mathematics achievement. The order of importance of the gifted students’ mathematical abilities on mathematics achievement is as spatial thinking, mathematical reasoning and problem-solving. Spatial thinking, mathematical reasoning and problem-solving are the significant predictors of mathematics achievement.

Concurrence of folding and remagnetization events in the Monterrey Salient (NE Mexico)

Carbonate formations from many locations reveal magnetizations that are secondary. Attaching a numerical age to these remagnetizations would provide information on orogenic processes. To contribute to the effort of assigning an age to remagnetization events, Lower Cretaceous formations from the Monterrey Salient in northeast Mexico were sampled. Individual fold tests reveal eight site-pair synfolding remagnetizations (set A) of Eocene age. The remanence is a chemical remanent magnetization (CRM) carried by magnetite. The magnetization of set B is possibly due to an early carbonate alteration that produced a remanence significantly older than folding. A complexity of set B is that the site pairs reveal k-versus-unfolding percentage diagrams with maximum unfolding peaks at 100 to 125%. An explanation of multiple deformation phases with an earlier horizontal folding phase around a non-plunging horizontal axis and a later vertical axis rotation is suggested for the past 100% peaks of the B sites. The latter deformation, rotation about a vertical axes, is revealed by a declination-strike test in set A sites and site means of the full collection that deviate counterclockwise from the reference declination. By combining synfolding results with published 40Ar/39Ar illite ages of folding (Fitz-Diaz et al., 2016), remagnetization ages in set A sites of 48–52Ma are obtained. The magnetization in set B sites is likely older, though not well constrained. Interestingly, prior results from the central Sierra Madre Oriental, to the south, show two remagnetization events, Late Cretaceous and Early Eocene in age, in a succession from W to E (Nemkin et al., 2015). The age of folding and remagnetization acquisition in set A sites along the Monterrey Salient are concurrent with the frontal, remagnetized folds in the central Sierra Madre Oriental. Thus, the timing of major remagnetization in the Monterrey Salient occurred in the Eocene.

False-negative reactions to the comparative intradermal tuberculin test for bovine tuberculosis

ABSTRACT: According to the Brazilian National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT), the routine tests for the diagnosis of bovine tuberculosis in the country are the simple intradermal tuberculin test (SITT) of the Ministry of Agriculture, Livestock and Food Supply (MAPA), the caudal fold test and the comparative intradermal tuberculin test (CITT). The latter is also used as a confirmatory test. A group of 53 animals from three dairy herds in a focal area for bovine tuberculosis, that were submitted to depopulation in the state of Rio Grande do Sul, were submitted to the CITT. Tissues were cultured and the resulting colonies were confirmed by PCR and DNA sequencing. Among the 53 animals analyzed using the CITT, 32 (60.4%) were negative, 14 (26.4%) were positive and seven (13.2%) results were inconclusive. The CITT detected 11 of the 39 animals with culture-confirmed M. bovis infection as positive. Among the total of 14 uninfected animals based on cultures, the CBT detected eight as negative. Thus, the CITT demonstrated sensitivity of 28.2% and specificity of 57.1% for the population sampled. A total of 24/32 (75.0%) of the animals with negative CITT results were culture positive (confirmed by PCR) and were considered false negatives based on the CITT. The maintenance of these false-negative animals in herds has serious implications for the control of the disease, since they can be a source of infection. The addition of complementary tests could help identify such animals and increase the odds of diagnostic success.

In this issue – December 2017

In this issue – December 2017

Reduced mental load in learning a motor visual task with virtual 3D method

AbstractDistance learning is expanding rapidly, fueled by the novel technologies for shared recorded teaching sessions on the Web. Here, we ask whether 3D stereoscopic (3DS) virtual learning environment teaching sessions are more compelling than typical two‐dimensional (2D) video sessions and whether this type of teaching results in superior learning. The research goal was to compare learning in 2 virtual learning scenarios—on 2D displays and with an identical 3DS scenario. Participants watched a 2D or 3DS video of an instructor demonstrating a box origami paper‐folding task. We compared participants' folding test scores and self‐assessment questionnaires of the teaching scenarios and calculated their cognitive load index (CLI) based on electroencephalogram measurements during the observation periods. Results showed a highly significant difference between participants' folding test scores, CLI, and self‐assessment questionnaire results in 2D compared to 3DS sessions. Our findings indicate that employing stereoscopic 3D technology over 2D displays in the design of emerging virtual and augmented reality applications in distance learning has advantages.

New Early Cretaceous palaeomagnetic and geochronological results from the far western Lhasa terrane: Contributions to the Lhasa-Qiangtang collision

To better constrain the Lhasa-Qiangtang collision, a combined palaeomagnetic and geochronological study of the far western Lhasa terrane was conducted on the Duoai Formation lava flows (~113–116 Ma), as well as on the Early Cretaceous Jiega Formation limestone. Following detailed rock magnetic, petrographical, and palaeomagnetic experiments, characteristic remanent magnetisation directions were successfully isolated from most samples using principal component analysis. The tilt-corrected direction groups yielded a palaeopole at 69.1°N, 319.8°E with A95 = 4.8° (N = 19). A primary origin for the magnetisation is consistent with positive fold tests. Our results from the Early Cretaceous units, combined with published palaeomagnetic data obtained from Cretaceous strata from the Lhasa and western Qiangtang terranes, show that these two terranes had already collided by the Early Cretaceous, the Lhasa terrane had a relatively east-west alignment, and it remained at a relatively stable palaeolatitude during the entire Cretaceous. Comparing the Cretaceous palaeolatitude calculated for the western Lhasa terrane with those from Eurasia and Mongolia suggests a latitudinal convergence of ~1400 ± 290 km and ~1800 ± 300 km, respectively, since the Early Cretaceous.

Paleomagnetism of the Cretaceous Galula Formation and implications for vertebrate evolution

This study uses magnetostratigraphy to help constrain the age of the paleontologically important Galula Formation (Rukwa Rift Basin, southwestern Tanzania). The formation preserves a Cretaceous vertebrate fauna, including saurischian dinosaurs, a putative gondwanatherian mammal, and notosuchian crocodyliforms. With better dating, the Galula Formation and its fossils help fill a temporal gap in our understanding of vertebrate evolution in continental Africa, enabling better evaluation of competing paleobiogeographic hypotheses concerning faunal exchange throughout Gondwana during the Cretaceous. Paleomagnetic samples for this study were collected from the Namba (higher in section) and Mtuka (lower in section) members of the Galula Formation and underwent stepwise thermal demagnetization. All samples displayed a strong normal magnetic polarity overprint, and maximum unblocking temperatures at approximately 690 °C. Three short reversed intervals were identified in the Namba Member, whereas the Mtuka Member lacked any clear reversals. Given the relatively limited existing age constraints, one interpretation correlates the Namba Member to Chron C32. An alternative correlation assigns reversals in the Namba Member to recently proposed short reversals near the end of the Cretaceous Normal Superchron (Chron C34), a time that is traditionally interpreted as having stable normal polarity. The lack of reversals in the Mtuka Member supports deposition within Chron C34. These data suggest that the Namba Member is no older than Late Cretaceous (Cenomanian-Campanian), with the Mtuka Member less well constrained to the middle Cretaceous (Aptian-Cenomanian). The paleomagnetic results are supported by the application of fold and reversal tests for paleomagnetic stability, and paleomagnetic poles for the Namba (246.4°/77.9°, α95 5.9°) and Mtuka (217.1°/72.2°, α95 11.1°) members closely matching the apparent polar wander path for Africa during the Late Cretaceous. These results confidently indicate a Late Creteceous age assignment for the Namba Member of the Galula Formation, a unit that has yielded key crocodyliform (e.g., Pakasuchus; Rukwasuchus) and dinosaur (e.g., Rukwatitan; Shingopana) fossils from eastern Africa.

Cenozoic clockwise rotation of the Chuan Dian Fragment, southeastern edge of the Tibetan Plateau: Evidence from a new paleomagnetic study

Late Eocene-early Oligocene red beds of the Ninglang Formation were sampled from 23 sites in the Yongsheng area, which comprises the northwestern part of the Chuan Dian Fragment (CDF) of the South China Block. The higher temperature components (HTC) were isolated by stepwise thermal demagnetization between ∼300–680°C and they passed the fold test. However, all the HTCs are of normal polarity, which appears to conflict with the frequent occurrence of reversed polarities during the late Eocene-early Oligocene, and therefore the possibility of remagnetization needs to be considered. Widespread secondary hematite was detected in the red beds that further indicates the remagnetization of samples. From the magmatic–metallogenic events in the sampling area, we propose an early Oligocene (∼35Ma) remagnetization event that was most likely related to porphyritic intrusions induced by fluid activity. Comparison of the pole calculated from the remagnetized remanent directions with the ∼35Ma paleomagnetic pole for Eurasia indicated that the degree of clockwise rotation in the Yongsheng area is 17.0±4.1° relative to stable Eurasia. The rotation value is consistent at the 95% confidence level with results obtained from Paleogene and Cretaceous strata in other areas of the CDF. Paleomagnetic data indicate that a consistent clockwise rotation of 20.6±6.3° occurred in different areas in the CDF: at Yongsheng, Zhupeng, Bailu, Dayao, Chuxiong west and Jianchuan. Careful analysis of the paleomagnetic data and the geometrical characteristics of the Ailao Shan–Red River shear zone indicates that the rotation process was separated into two discrete intervals: Approximately 11° of quasi-rigid clockwise rotation occurred between ∼35 and 12.7Ma compared to stable Eurasia, which may have been accompanied by strike-slip movement of the Ziyun-Luodian fault, caused by west-to-east compression induced by the northeastern indention of the Eastern Himalayan Syntaxis. Subsequently, a clockwise rotation of about 10° of the CDF with respect to stable Eurasia is inferred from the paleomagnetic results since 12.7Ma, which is consistent with the change in the geometry of the Ailao Shan–Red River shear zone around the western Chuxiong Basin. The later CW rotation was related to shearing movement of the Xianshuihe–Xiaojiang fault.