Social rifts in Colombia

Includes bibliography

New insights into magmatism and changing rift styles in the evolution of the Gulf of California

The Gulf of California (GoC) has been an important focus site for understanding the spatial and temporal evolution of rifts, with recent studies concluding: 1) rapid crustal rupturing within 10 Myrs; 2) surprisingly abrupt variations in rifting style and magmatism with apparently wide magma-poor and narrow, magmatic rift segments; and 3) that high sedimentation rates may promote switching from wide to narrow rift modes or thermally blanket the crust to enhance rift magmatism. Critical to these conclusions is the onset of rifting at~12 Ma following the cessation of subduction. New field-based volcanostratigraphic and geochronologic studies along the southeastern GoC margin reveal Early Miocene (~25-18 Ma) bimodal volcanism in wide rifting mode (~400 km width), followed by a mid-Miocene (~18-12 Ma) phase of dominantly intermediate composition magmatism in and around the nascent GoC with lavas/domes often emplaced into actively subsiding basins, but contemporaneous with bimodal volcanism regionally. Flat-lying intraplate basaltic lava fields emplaced ~12-10 Ma along the GoC east coast abut tilted blocks of ~20 Ma ignimbrites onshore, and also occur offshore. The reduction in crustal thickness from ~55 to 20 km along the eastern GoC edge must have been largely achieved by 12 Ma. Extension has demonstrably began earlier than previously thought, downplaying rapid rifting and any thermal effects from <6 Ma sedimentation. New age data from onshore indicate significant structurally controlled corridors of magmatism during 18-12 Ma extension in apparently magma-poor rift segments, and this magmatism temporally coincides with the switch from wide to narrow rifting.

Termocronologia (U-Th)He e reativação da margem continental do sudeste do Brasil: seção Serra da Mantiqueira - Gráben da Guanabara

A evolução da margem continental do sudeste do Brasil tem sido discutida por diversos autores desde meados do século passado até os dias atuais, especialmente no contexto da origem e evolução dos escarpamentos e das bacias tafrogênicas. Buscou-se contribuir com novos dados sobre a evolução da área a partir da aplicação da termocronologia de baixa temperatura (U-Th)/He em apatita, que oferece uma sensibilidade significativa para registrar movimentações tectônicas na crosta superior. Foi possível obter idades em 107 cristais de apatita de 18 amostras do embasamento coletadas no perfil com orientação NW-SE, numa seção entre a Serra da Mantiqueira e o Gráben da Guanabara. As idades corrigidas variam entre 250,1 8,7 Ma e 43,5 1,9 Ma (2 σ) e as não corrigidas entre 174,13 3,03 Ma e 27,07 0,60 Ma (1 σ). O Neocretáceo, o Eocretáceo e o Paleoceno são os principais registros no conjunto de dados, em ordem de importância. No Neocretáceo, o intervalo entre 83,6 e 72,1 Ma (Campaniano) representa o maior destaque nos registros termocronológicos, embora os outros registros (Maastrichtiano e Santoniano) também estejam presentes e sejam importantes. As idades do Neocretáceo destacam a importância dos eventos tectonomagmáticos e soerguimento regional na história térmica dessa área, inclusive com idades (~86 Ma) atribuídas ao contexto de soerguimento da Serra do Mar. As idades do Eocretáceo indicam o registro de eventos térmicos mais antigos, vinculados à evolução pré-rifte. Já os dados do Paleoceno estariam associados ao evento de reativação responsável pela implantação do sistema de riftes continentais (~65 Ma) e as idades do Eoceno, restritas à borda de falha da bacia de Resende (49,7 Ma e 43,5 Ma), à reativação do sistema de riftes nessa área. A dispersão de idades foi interpretada como efeito dos danos de radiação já que muitos grãos apresentam correlação entre idade e concentração de urânio (eU). Os padrões de tempo-temperatura (t-T), definidos a partir dos modelos HeFTy calibrados para o modelo de difusão que considera os efeitos de danos de radiação nos cristais, registraram eventos de resfriamento rápido, os quais mostram correlação direta com episódios de reativação e soerguimento na margem continental e com registros nas bacias continentais e marginais. O padrão de aumento das idades com a elevação, assim como da costa em direção ao interior é observado, mas mostra-se alterado pela ocorrência de idades mais jovens associadas à complexa evolução dessa margem continental com desnivelamentos de blocos vinculados à tectônica pós-rift, numa situação que ressalta a influência dos episódios de reativação. As estimativas de denudação total variam entre 1,2 e 2,8 km. As taxas de erosão variam entre 15,2 e 35,3 m/Ma. A evolução da área indica não apenas a influência de um evento específico mas, possivelmente, uma combinação de episódios que se alternaram e/ou atuaram em conjunto em determinados períodos. Os eventos de reativação mais antigos, combinados com os mais recentes, exibem os seus remanescentes na paisagem (serras da Mantiqueira e do Mar e os grábens e bacias sedimentares) e assumem papel fundamental na evolução da área. Os registros de tais episódios podem ser observados nas histórias térmicas das rochas e nos depósitos correlativos nas bacias sedimentares marginais e intracontinentais.

Propagators and ridge jumps in a back-arc basin, the West Philippine Basin

We explore the tectono-magmatic processes in the western West Philippine Basin, Philippine Sea Plate, using bathymetric data acquired in 2003 and 2004. The northwestern part of the basin formed through a series of northwestward propagating rifts. We identify at least five sequences of propagating rifts, probably triggered by mantle flow away from the mantle thermal anomaly that is responsible for the origin of the Benham and Urdenata plateaus. Gravitational forces caused by along-axis topographic gradient and a similar to 30 degrees ridge reorientation appear to also be driving the rift propagations. The along-axis mantle flow appears to be reduced and deflected along the Luzon-Okinawa fracture zone, because the spreading system remained stable west of this major fault zone. North-east of the Benham plateau, a left-lateral fracture zone has turned into a NE-SW-trending spreading axis. As a result, a microplate developed at the triple junction.

化德群和土门群沉积岩碎屑锆石研究：对华北克拉通基底及元古宙盆地演化的指示意义

The Huade Group, consisting of low-grade and un-metamorphosed sedimentary rocks with no volcanic interlayer, is located at the northern margin of the North China craton and adjoining the south part of the Central Asian Orogenic Belt. It is east to the Paleo- to Meso-Proterozoic Bayan Obo and Zhaertai-Langshan rifts and northwest to the Paleo- to Neo-proterozoic Yanshan aulacogen, in which the typical Changcheng, Jixian and Qingbaikou systems are developed. The Huade Group are mainly composed of pebbly sandstones, sandstones, greywackes，shales，calc-silicate rocks and limestones, partly undergoing low-grade metamorphism and being changed to meta-sandstones, schists, phyllites, slates and crystalline limestones or marbles. The stratigraphic sequences show several cycles of deposition. Each of them developed coarse clastic rocks – interbedded fine clastic rocks and pelites from bottom upward or from coarse clastic rocks to interbedded fine clastic rocks and pelites to carbonate rocks. The Tumen Group outcrop sporadically around or west to the Tanlu faults in western Shandong. They are mainly composed of pebbly sandstones, sandstones, shales and limestones. This thesis deals with the characteristics of petrology, geochemistry and sedimentary of the Huade Group and the Tumen Group, and discusses the LA-ICP-MS and SIMS U-Pb ages, Hf isotope and trace element composition of the detrital zircons from 5 meta-sandstone samples of the Huade Group and 3 sandstone samples of the Tumen Group. The age populations of the detrital zircons from the Huade Group are mainly ~2.5 Ga and ~1.85 Ga, and there are also minor peaks at ~2.0 Ga, ~1.92 Ga and ~1.73 Ga. Most of the detrital zircon grains of 2.47-2.57 Ga and a few of 1.63-2.03 Ga have Hf crust model ages of 2.7-3.0 Ga, and most of the detrital zircon grains of 1.63-2.03 Ga have Hf crust model ages of 2.35-2.7 Ga, with a peak at 2.54 Ga. The main age peaks of the detrital zircons from the Tumen Group are ~2.5 Ga、~1.85 Ga, 1.57 Ga, 1.5 Ga, 1.33 Ga and 1.2 Ga. Different samples from the Tumen Group have distinct Hf isotopic characteristics. Detrital zircon grains of ~2.52 Ga from one sandstone sample have 2.7-3.2 Ga Hf crust model ages, whereas zircon grains of 1.73-2.02 Ga and 2.31-2.68 Ga from another sample have Hf crust model ages of 2.95-3.55 Ga. Detrital zircon grains of Mesoproterozoic ages have Paleoproterozoic (1.7-2.25 Ga) crust model ages. Through detailed analyses of the detrital zircons from the Huade and Tumen Group and comparison with those from the sedimentary rocks of similar sedimentary ages, the thesis mainly reaches the following conclusions: 1. The youngest age peaks of the detrital zircons of 1.73 Ga constrains the sedimentary time of the Huade Group from late Paleoproterozoic to Mesoproterozoic. 2. The age peaks of detrital zircons of the Huade Group correspond to the significant Precambrian tectonic-thermal events of the North China craton. The basement of the North China craton is the main provenance of the Huade Group, of which the intermediate to high grade metamorphic sedimentary rocks are dominant and provide mainly 1.85-1.92 Ga sediments. 3. The Huade basin belongs to the North China craton and it is suggested that the northern boundary of the North China craton should be north to the Huade basin. 4. The stratigraphic characteristics indicate the Huade Group formed in a stable shallow-hypabyssal sedimentary basin. The rock association and sedimentary time of the Huade Group are similar to those of the Banyan Obo Group and the Zhaertai Group, and they commonly constitute late Paleoproterozoic to Mesoproterozoic continental margin basins along the northern margin of the North China craton. 5. The continental margin basins would have initiated coeval with the Yanshan and Xiong’er aulacogens. 6. The ages of the detrital zircons from the Tumen Group and the Penglai Group at Shandong peninsula and the Yushulazi Group at south Liaoning are similar, so their sedimentary time is suggested to be Neoproterozoic，coeval with the Qingbaikou system. The detrital zircon ages of 1.0-1.2 Ga from the Tumen Group, the Penglai Group and the Yushulazi Group indicate that there have being 1.0-1.2 Ga magmatic activities at the eastern margin of the North China craton. 7. The U-Pb age populations of the detrital zircons from the late Paleoproterozoic to Neoproterozoic sedimentary rocks suggest that the main Precambrian tectonic-thermal events of the North China craton happened at ~2.5 Ga and ~1.85 Ga. But the events at 2.7 Ga and 1.2 Ga are also of great significance. Hf isotope characteristics indicate that the significant crust growth periods of the North China craton are 2.7-3.0 Ga and ~2.5 Ga.

内蒙古白云鄂博地区元古宙构造-岩浆演化史与超大型REE-Nb-Fe矿床成因

Bayan Obo giant REE-Nb-Fe deposit in the northen margin of the North China Craton (NCC) is well known in the world for its abundant rare earth element resources. There is nearly one hundred year of studying history in substance component, chronology and geochemistry of the ore deposit, since the main ore body was found in 1927. However, there still exist remarkable divergences in genesis, mineralized age and material origin. Especially the REE enrichment mechanism leaves us a secret. Recent research shows that the Bayan Obo ore deposit likely resulted from the carbonatite magma activity, which is a favorable factor for REE accumulation. Based on the analysis of tectonic evolution history of north margin of NCC this thesis mainly discussed the formation background of cratonic margined rifts in Bayan Obo, and presented the analytical results of formation environment, intrusion age and deep origin of Proterozoic carbonatite magma. These research results can provide evidence for ore genesis. LA ICP-MS U-Pb dating on zircon shows that the Neoarchean basement was mainly composed of calc-alkaline TTG gneisses (2588±16Ma). The collision orogeny movement of the northen margin of the NCC between 2.0 Ga to 1.9 Ga brought the swarm of diorite-granodiotite magma (2023±16Ma) and intense regional metamorphism event (1906.3±7.7 Ma to 1892.7±6.7 Ma). In the sequent super continent break up background, intense metamorphic and deformed basement complex was uplifted to the surface suffered denudation, forming Mesoproterozoic Bayan Obo group in the contemporary continental margin rifts. The uplift of basement complex and formation of continental rifts were likely related with mantle plume activity. Evidence from petrological and geochemical data suggests that abundant alkaline-basic magma resulted from enhancement of continental breakup activity, that separated into carbonatite veins and mafic dykes by melt immiscibility mechanism, intruded in Bayan Obo margin rifts at the late stage of extension movement. Carbonatite veins can be divided into three main types by mineral composition: dolomite carbonatite, dolomite-calcite coexistent carbonatite and calcite carbonatite. Intrusion relationship between different types of carbonatite veins show that the calcite carbonatite veins were formed latter than the dolomite type as well as the coexistent type. Moreover, geochemical data also reveals successive and evolutive character between them. The content of REE increases together with the calcite minerals component. That is to say that REE gradually accumulated as the evolution of carbonatite magma. High precision Sm-Nd isochron data shows that the intrusion age of carbonatite veins was at 1319±48Ma. Moreover, the REE mineralization age in calcite carbonatite veins was around 1275±87Ma that is consistent with the intrusion age in error range. According to these data the abundant REE already existed in the carbonatite magma before intrusion and result in the earlier ore mineralization. The average age of mineralized dolomite was at 1353±100Ma, and the mineralization age of apatite in coarse grain dolomite was around 1329±150Ma. These data is consistent with carbonatite. Considering the coincident rare, trace element and isochron composition between them, it is presumed that mineralized dolomite was also the carbonatite intrusion and was the mainly factor for huge REE enrichment.

扬子板块西部大陆地幔地球化学特征及壳幔演化－有关基性岩超基性岩的地球化学研究

The continental mantle geochemical characteristics and crust-mantle evolution in the west of Yangtze Plate was discussed through the study of some within-plate basic-ultrabasic rocks from Lower Proterozoic to Later Paleozoic in this paper. In the Lower Proterozoic, the plate subduction between the pre-Tethys Proterozoic Ocean Plate and paleo-Yangtze Plate induced some basic volcanic formed in the island arc-back arc surrounding, which were represented by Ailaoshan Group-Dibadu Formation-Dahongshan Group, and there existed EM I component in the mantle source. The Middle Proterozoic Caiziyuan peridotite was formed in the epicontinental basin at the ocean-land boundary or within-continent rift basin. Its mantle source could be metasomatized by the dehydration fluid of subducted plate, and much initial radioactive ~(143)Nd was added to the source. In the Later Proterozoic, some rifts at the epicontinent or within-continent was formed due to the pre-Tethys oceanic plate subduction, and within-plate hot-spot Dahongshan diabase came into being. The whole-rock isochronal age of diabase is 1066±110Ma, and its mantle source was enriched Nd isotope and trace element which was related to the primary volatile component from asthenosphere and mantle plume. Its mantle source was included "FOZO" component representing mantle plume. The layer ultramafic rocks located at the Panxi Rift in the Middle-Later Paleozoic were resulted from different period and source. The early ultramafic indicated the incipient action of Panxi Rift, which is residue of continental lithospheric partial melting. Its mantle source involved subducted material and had distinct EM II component. The Emeishan basalt in the Later Paleozoic was typical continental flood basalt and its source also contained EM II component. The subduction of paleo-Tethys Ocean Plate provided essential dynamic condition for the large-scale opening of Panxi Rift, while the mantle plume supplied much material for Emeishan basalt. However, the plume was contaminated by the metasomatized continental mantle lithosphere in its upwelling process, which resulted in the Sr isotopic and incompatible elemental enrichment, and the Nd isotope kept down the weak-depleted character of mantle plume. The magmatic history in the west of Yangtze Plate is the tectonic process between pre-Tethys, paleo-Tethys Oceanic Plate and Yangtze Plate in a long history. Due to the subduction of oceanic plate, the crustal source material took part in the crust-mantle evolution widely. the continental mantle lithosphere in the west of Yangtze Plate was metasomatized by the fluid released by the subducted plate and the primary volatile from deeper mantle, and the mantle source include obvious enriched component.

Volcanic rifting at Martian grabens

Cook, Anthony; Mege, D.; Garel, E.; Lagabrielle, Y., (2003) 'Volcanic rifting at Martian grabens', Journal of Geophysical Research 108(E5) pp. 1-33 RAE2008

Strategic non-cooperation as soft balancing: Why Iraq was not just about Iraq

Many commentators explain recent transatlantic rifts by pointing to diverging norms, interests and geopolitical preferences. This paper proceeds from the premise that not all situations of conflict are necessarily due to underlying deadlocked preferences. Rather, non-cooperation may be a strategic form of soft balancing. That is, more generally, if they believe that they are being shortchanged in terms of influence and payoffs, weaker states may deliberately reject possible cooperation in the short run to improve their influence vis-à-vis stronger states in the long run. This need not be due to traditional relative gains concern. States merely calculate that their reputation as a weak negotiator will erode future bargaining power and subsequently their future share of absolute gains. Strategic non-cooperation is therefore a rational signal of resolve. This paper develops the concept of strategic non-cooperation as a soft balancing tool and applies it to the Iraq case in 2002-2003. © 2005 Palgrave Macmillan Ltd.

Evidence of mass failure in the Hess Deep Rift from multi-resolutional bathymetry data

New regional swath and near-bottom bathymetric data provide constraints on shallow structures at the Hess Deep Rift, an oceanic rift that exposes the crust and upper mantle of fast-spreading oceanic lithosphere created at the East Pacific Rise. These data reveal the presence of a lobate structure with a length of ~ 4 km and a width of ~ 6 km south of an Intrarift Ridge, north of Hess Deep. The lobe consists of a series of concentric benches that are widest in the center of the lobe and narrower at the edges, with a dominant bench separating two distinct morphologic regions in the lobe. There are two end-member possible interpretations of this feature: 1) the lobate structure represents a mass failure with little translation that contains coherent blocks that preserve rift-related lineaments; or 2) it represents degraded tectonic structures, and the lobate form is accounted for by, for example, two intersecting faults. We favor the slump interpretation because it more readily accounts for the lobate form of the feature and the curved benches and based on the presence of other similar lobes in this region. In the slump model, secondary structures within the benches may indicate radial spreading during or after failure. The large lobate structure we identify south of the Intrarift Ridge in Hess Deep is one of the first features of its kind identified in an oceanic rift, and illustrates that mass failure may be a significant process in these settings, consistent with the recognition of their importance in mid-ocean ridges, oceanic islands, and continental rifts. Understanding the structure of the Hess Deep Rift is also important for reconstructing the section of fast-spreading oceanic crust exposed here.

Intraplate earthquake swarm in Belo Jardim, NE Brazil: reactivation of a major Neoproterozoic shear zone (Pernambuco Lineament)

Intraplate earthquakes in stable continental areas have been explained basically by reactivation of pre-existing zones of weakness, stress concentration, or both. Zones of weakness are usually identified as sites of the last major orogeny, provinces of recent alkaline intrusions, or stretched crust in ancient rifts. However, it is difficult to identify specific zones of weakness and intraplate fault zones are not always easily correlated with known geological features. Although Northeastern Brazil is one of the most seismically active areas in the country (magnitudes 5 roughly every 5 yr), with hypocentral depths shallower than similar to 10 km and seismic zones as long as 30-40 km, no clear relationship with the known surface geology can be usually established with confidence, and a clear identification of zones of weakness has not yet been possible. Here we present the first clear case of seismic activity occurring as reactivation of an old structure in Brazil: the Pernambuco Lineament, a major Neoproterozoic shear zone. The 2004 earthquake swarm of Belo Jardim (magnitudes up to 3.1) and the recurrent activities in the nearby towns of Sao Caetano and Caruaru (magnitudes up to 4.0 and 3.8), show that the Pernambuco Lineament is a weak zone. A local seismic network showed that the Belo Jardim swarm of 2004 November occurred by normal faulting on a North dipping, E-W oriented fault plane in close agreement with the E-W trending structures within the Pernambuco Lineament. The Belo Jardim activity was concentrated in a 1.5 km (E-W) by 2 km (downdip) fault area, and average depth of 4.5 km. The nearby Caruaru activity occurs as both strike-slip and normal faulting, also consistent with local structures of the Pernambuco Lineament. The focal mechanisms of Belo Jardim, Caruaru and S. Caetano, indicate E-W compressional and N-S extensional principal stresses. The NS extension of this stress field is larger than that predicted by numerical models such as those of Coblentz & Richardson and we propose that additional factors such as flexural stresses from the nearby Sergipe-Alagoas marginal basin could also affect the current stress field in the Pernambuco Lineament.

The intraplate Porto dos Gauchos seismic zone in the Amazon craton - Brazil

The largest earthquake observed in the stable continental interior of the South American plate occurred in Serra do Tombador, Mato Grosso state - Brazil, on January 31,1955 with a magnitude of 6.2 m(b). Since then no other earthquake has been located near the 1955 epicentre. However, in Porto dos Gauchos, 100 km northeast of Serra do Tombador, a recurrent seismicity has been observed since 1959. Both Serra do Tombador and Porto dos Gauchos are located in the Phanerozoic Parecis basin. Two magnitude 5 earthquakes occurred in Porto dos Gauchos, in 1998 and 2005, with intensities up to VI and V, respectively. These two main shocks were followed by aftershock sequences lasting more than three years each. Local seismic stations have been deployed by the Seismological Observatory of the University of Brasilia since 1998 to study the ""Porto dos Gauchos"" seismic zone (PGSZ). A local seismic refraction survey was carried out with two explosions to help define the seismic velocity model. Both the 1998 and 2005 earthquake sequences occurred in the same WSW-ENE oriented fault zone with right-lateral strike-slip mechanisms. The epicentral zone is in the Parecis basin, near its northern border where there are buried grabens, generally trending WNW-ESE, such as the deep Mesoproterozoic Caiabis graben which lies partly beneath the Parecis basin. However, the epicentral distribution indicates that the 1998 and 2005 sequences are related to a N60 degrees E fault which probably crosses the entire Caiabis graben. The 1955 earthquake, despite the uncertainty in its epicentre, does not seem to be directly related to any buried graben either. The seismicity in the Porto dos Gauchos seismic zone, therefore, is not directly related to rifted crust. The probable direction of the maximum horizontal stress near Porto dos Gauchos is roughly E-W, consistent with other focal mechanisms further south in the Pantanal basin and Paraguay. but seems to be different from the NW-SE direction observed further north in the Amazon basin. The recurrent seismicity observed in Porto dos Gauchos, and the large 1955 earthquake nearby, make this area of the Parecis basin one of the most important seismic zones of Brazil. (C) 2009 Elsevier B.V. All rights reserved.

A review of the tectonic evolution of the Sunsas belt, SW Amazonian Craton

The Sunsas-Aguapei province (1.20-0.95 Ga), SW Amazonian Craton, is a key area to study the heterogeneous effects of collisional events with Laurentia, which shows evidence of the Grenvillian and Sunsas orogens. The Sunsas orogen, characterized by an allochthonous collisional-type belt (1.11-1.00 Ga), is the youngest and southwestern most of the events recorded along the cratonic fringe. Its evolution occurred after a period of long quiescence and erosion of the already cratonized provinces (>1.30 Ga), that led to sedimentation of the Sunsas and Vibosi groups in a passive margin setting. The passive margin stage was roughly contemporary with intraplate tectonics that produced the Nova Brasilandia proto-oceanic basin (<1.21 Ga), the reactivation of the Ji-Parana shear zone network (1.18-1.12 Ga) and a system of aborted rifts that evolved to the Huanchaca-Aguapei basin (1.17-1.15 Ga). The Sunsas belt is comprised by the metamorphosed Sunsas and Vibosi sequences, the Rincon del Tigre mafic-ultramafic sill and granitic intrusive suites. The latter rocks yield epsilon(Nd(t)) signatures (-0.5 to -4.5) and geochemistry (S,1, A-types) suggesting their origin associated with a continental arc setting. The Sunsas belt evolution is marked by ""tectonic fronts"" with sinistral offsets that was active from c. 1.08 to 1.05 Ga, along the southern edge of the Paragua microcontinent where K/Ar ages (1.27-1.34 Ga) and the Huanchaca-Aguapei flat-lying cover attest to the earliest tectonic stability at the time of the orogen. The Sunsas dynamics is coeval with inboard crustal shortening, transpression and magmatism in the Nova Brasilandia belt (1.13-1.00 Ga). Conversely, the Aguapei aulacogen (0.96-0.91 Ga) and nearby shear zones (0.93-0.91 Ga) are the late tectonic offshoots over the cratonic margin. The post-tectonic to anorogenic stages took place after ca. 1.00 Ga, evidenced by the occurrences of intra-plate A-type granites, pegmatites, mafic dikes and sills, as well as of graben basins. Integrated interpretation of the available data related to the Sunsas orogen supports the idea that the main nucleus of Rodinia incorporated the terrains forming the SW corner of Amazonia and most of the Grenvillian margin, as a result of two independent collisional events, as indicated in the Amazon region by the Ji-Parana shear zone event and the Sunsas belt, respectively. (C) 2009 Elsevier Ltd. All rights reserved.