making geological sense of big data in sedimentary provenance analysis abstract sedimentary provenance studies increasingly apply multiple chemical mineralogical and isotopic proxies to many samples the resulting datasets are often so large containing thousands of numerical values and complex comprising multiple dimensions that it is warranted to use the internet era term big data to describe them this paper introduces multidimensional scaling mds generalised procrustes analysis gpa and individual differences scaling indscal a type of 3 way mds algorithm as simple yet powerful tools to extract geological insights from big data in a provenance context using a dataset from the namib sand sea as a test case we show how mds can be used to visualise the similarities and differences between 16 fluvial and aeolian sand samples for five different provenance proxies resulting in five different configurations these configurations can be fed into a gpa algorithm which translates rotates scales and reflects them to extract a consensus view for all the data considered together alternatively the five proxies can be jointly analysed by indscal which fits the data with not one but two sets of coordinates the group configuration which strongly resembles the graphical output produced by gpa and the source weights which can be used to attach geological meaning to the group configuration for the namib study the three methods paint a detailed and self consistent picture of a sediment routing system in which sand composition is determined by the combination of provenance and hydraulic sorting effects

a recipe for microcontinent formation accreted slivers of continental margins are common in the geologic record but the processes that lead to their formation are poorly understood we observe an association of plume related microcontinent isolation and subsequent long term asymmetries in oceanic crustal accretion based on four recent examples the seychelles in the indian ocean jan mayen in the norwegian greenland sea and the east tasman plateau and the gilbert seamount complex in the tasman sea these microcontinents formed by rerifting of a young continental margin 25 m y old in the vicinity of a mantle plume stem followed by asymmetric seafloor spreading two dimensional numerical stochastic basin modeling suggests that a yield strength minimum along the landward edge of a rifted margin thermally enhanced by heating from a mantle plume may cause a spreading ridge to jump onto this zone of weakness this action isolates a passive margin segment the association of large igneous provinces and microcontinents should be useful for identifying similar events in the geological record

δ2 triterpenes early intermediates in the diagenesis of terrigenous triterpenoids a series of 2 triterpenoids oleana 2 12 diene oleana 2 13 18 diene oleana 2 18 diene ursa 2 12 diene and taraxera 2 14 diene has been identified in holocene buried mangrove sediments florida usa by comparison of the mass spectra of and by co injections with authentic standards in the oligocene brandon lignite vermont usa oleana 2 12 diene and oleana 2 13 18 diene were also identified along with two a ring contracted amyrin derivatives by comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup 2 ene from lupan 3 one these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules such as and amyrin and taraxerol the identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids

seismic reflection evidence for a dangerous grounds miniplate no extrusion origin for the south china sea the collision of india and asia has caused large strike slip faults to form in east asia resulting in the extrusion of crustal blocks toward the southeast since the eocene as a result of the indentation of rigid india into asia it has been suggested that the south china sea opened as a result of relative motion between a rigid indochina sundaland block and china alternative models propose that rifting and seafloor spreading were driven by trench forces to the south we test these competing models by analysis of seismic reflection profiles across the boundary between sundaland and the southern rifted margin known as the dangerous grounds we show that the southern boundary of the dangerous grounds is a subduction zone that jammed in the middle miocene to the west the dangerous grounds are bounded by a strike slip zone also active until similar to 16 ma that becomes diffuse south of the now inactive south china sea seafloor spreading center we place the western edge of the dangerous grounds just to the east of the natuna arch lupar line the west baram line is confirmed as originating as a major strike slip fault within the dangerous grounds and is continuous with the red river fault zone because the dangerous grounds were independent of sundaland until similar to 6 ma its motion cannot have been constrained by motion of this block making extrusion impossible as a mechanism to rift the south china sea se motion by both the dangerous grounds and sundaland suggests subduction forces were the primary trigger for plate motions our reconstruction places a similar to 280 km upper limit on the motion on the red river fault and a similar to 1400 km width to the paleo south china sea

shear wave velocity structure of reed bank southern continental margin of the south china sea abstract the shear wave velocity structure of a wide angle seismic profile obs973 2 across reed bank in the southern continental margin of the south china sea scs is simulated by 2 d ray tracing method based on its previous p wave model this profile is 369 km long and consists of fifteen three component ocean bottom seismometers obs the main results are as follows 1 the model consists of seven layers and the shear wave velocity increases from 0 7 km s at the top of sediment layer to 4 0 km s in the lower crust 2 the moho depth decreases from 20 22 km at the reed bank to 9 11 km at the deep oceanic basin with the shear wave velocity of 4 2 km s below the moho 3 the v p v s ratio decreases with depth through the sedimentary layers attributed to increased compaction and consolidation of the rocks 4 in the continental upper crust at model distance 90 170 km s wave velocity 2 5 3 2 km s is relatively low and v p v s ratio 1 75 1 82 is relatively high compared with the other parts of the crust corresponding to the lower p wave velocity in the previous p wave model and normal faults revealed by mcs data indicating that a strong regional extensional movement had occurred during the formation process of the scs at the reed bank area 5 the s wave structures indicate that reed bank crust has different rock compositions from that in the east section of the northern margin denying the presence of conjugate relationship of reed bank with dongsha islands according to p wave models and other data we inferred that reed bank and macclesfield were separated from the same continental crust during the rifting and break up process

full fit reconstruction of the south china sea conjugate margins although the south china sea margins have been well studied there are no full fit reconstructions that document the complex rifting history in a regional geodynamic context we restored conjugate margins to their original late cretaceous unstretched geometries and generated the first full fit reconstructions of the south china sea conjugate margins the impact of magmatic underplating on restoration and full fit reconstruction was estimated quantitatively the full fit reconstruction model includes restoration uncertainties and results in minimum gaps and overlaps between the restored conjugate margin geometries based on our restoration the full fit reconstruction and the continental basement thickness distribution we estimate that there was more extension of continental basement on the western part of the conjugate margins compared with the eastern margin prior to the initiation of seafloor spreading therefore the mid ocean ridge initially formed in the east and propagated westward to open the south china sea seafloor spreading propagated along the xisha trough during nw sub basin formation but continental breakup occurred along the southern side of the zhongsha xisha islands where the lithosphere was probably weaker than along the xisha trough consistent with the geometry and evolution of the nw sub basin and the southward jump of the mid oceanic ridge c 2015 elsevier b v all rights reserved

palaeocene early eocene inversion of the phuquoc kampot som basin se asian deformation associated with the suturing of luconia abstract the little explored cambodian and vietnamese phuquoc kampot som basin is a late jurassic to early cretaceous foreland basin developed in response to the build up of a palaeo pacific magmatic arc a combination of seismic data well data and outcrop geology complemented by fission track and u pb analysis is used to unravel the basin history this reveals a hitherto unknown earliest palaeogene basin inversion associated with the luconian suturing to se asia and the shutdown of palaeo pacific subduction underneath se asia the phuquoc kampot som basin and the khorat basin in thailand constitute the erosional remnants of a larger basin that covered large parts of se asia in late mesozoic time and subsequently became segregated during earliest palaeogene inversion and erosion inversion was focused along the several hundred kilometres long kampot and khmer chanthaburi fold belts that confine the phuquoc kampot som basin and merge with the mae ping and the three pagodas fault zones these connections together with local nw se trending sinistral transpressional faults offshore indicate a link between initial se asian left lateral strike slip faulting and the luconian suturing the separation between the once unbroken khmer chanthaburi fold belt and the phetchabun fold belt in thailand suggests a 50 100 km cenozoic left lateral offset across the mae ping fault zone

onland signatures of the palawan microcontinental block and philippine mobile belt collision and crustal growth process a review abstract the collision of the palawan microcontinental block with the philippine mobile belt had significantly influenced the geological evolution of the philippines multiple collisions involving several fragments through space and time resulted into the collage of terranes of varying origin exposed in this part of central philippines cusping of the overriding plate volcanic arc gap ophiolite emplacement incipient back arc rifting island rotation and tilting raised coastal terraces metamorphism intrusion of igneous rocks and steepened subducted slab as seen in focal mechanism solutions are some of the manifestations of this collision a late early miocene to early middle miocene age 20 16 ma is proposed for the major collision between the palawan indenter and the philippine mobile belt the collision boundary is located from the northern part of mindoro through the central mountain range swinging east of sibuyan island in the romblon island group and finally threading along the buruanga peninsula and eastern side of the antique ophiolite complex before exiting and connecting with the negros trench the collision through accretion and crustal thickening has contributed to the crustal growth of the philippine archipelago

new insight into a subduction related orogen a reappraisal of the geotectonic framework and evolution of the japanese islands abstract the geotectonic framework and the evolutionary history of the japanese islands need revision in accordance with the various geophysical geological evidence gathered by new methodologies in the recent years including seismic tomography vibroseis ground breaking seismic experiments and detrital zircon chronology these investigations have addressed various themes such as 1 seismic profile of the crust and mantle beneath the japanese islands 2 high precision ages of the protoliths of high p t metamorphic rocks and 3 provenance of terrigenous clastics the results have led to a number of important findings including 1 detection of a large mass of slab around the mantle boundary layer suggesting the long term oceanic subduction beneath japan 2 confirmation of the subhorizontal piled nappe structure for the entire crust of japan 3 finding a new high p t metamorphosed accretionary complex unit that represents the youngest blueschist in japan 4 finding of the oldest early cambrian arc batholith and cover sediments and 5 the identification of plural arc batholiths which have already been erased from the surface based on a synthesis of these new data this article presents a re evaluation of the conventional geotectonic subdivision of the subduction related orogen in japan re definition of the elements and their mutual boundaries and re consideration of the geotectonic evolution of the japanese islands in particular the historical change in provenance suggests that proto japan has experienced large scale tectonic erosion in multiple stages and the corresponding large amounts of continental crust materials were subducted for understanding the orogenic growth of japan during the last ca 500 million years the significance of tectonic erosion coupled with continental contraction as well as the oceanward accretionary growth requires further attention

geology and geochemistry of the clastic sequences from northwestern panay philippines implications for provenance and geotectonic setting abstract whole rock geochemical analysis of samples from the clastic sequences in northwestern panay revealed different compositional ranges for the buruanga peninsula and antique range the results provide additional evidence that northwestern panay consists of two distinct terranes as a result of the arc continent collision between the palawan microcontinental block and the philippine mobile belt major element compositions of clastic rocks from the buruanga peninsula saboncogon formation revealed that they belong to a continental margin tectonic setting whereas the antique range sedimentary rocks lagdo formation show an affinity to an oceanic island arc setting the fragante formation of the antique range shows some similarities in tectonic setting and provenance with buruanga peninsula clastic rocks which suggests a buruanga peninsula sediment contribution during its time of formation furthermore provenance analyses from combined major and trace element data indicate a more silicic source for the buruanga peninsula clastics and a more mafic derivation for the sedimentary rocks of the antique range these findings are consistent with previous studies suggesting that the buruanga peninsula forms part of the palawan microcontinental block and the antique range belongs to the philippine mobile belt the palawan microcontinental block is believed to be a drifted continental fragment from the mesozoic east asian accretionary complex in the southern part of the eurasian mainland which represents the continental margin setting and felsic source of the buruanga peninsula clastic rocks meanwhile the oceanic island setting and mafic source of the antique range clastic rocks represent the volcanic rocks of the philippine mobile belt that were formed as a result of the subduction of the leading oceanic edge of the palawan microcontinental block

paleomagnetism of palawan philippines abstract paleomagnetic studies have been carried out on palawan and on the island of busuanga to the north results from the cretaceous espina basalts of the calatuigas ophiolite in the south palawan block spb pass a fold test yield normal and reversed directions with a magnetic intensity and af demagnetization characteristics consistent with a primary trm the mean direction is 293 9 and an inclination of 5 8 with a k of 37 7 and an 95 of 12 6 this suggests that these ophiolites have moved northward and rotated counterclockwise by 66 13 with respect to the geocentric axial dipole gad field it also suggests that they were obducted from the south paleomagnetic directions from the jurassic busuanga cherts and the cretaceous guinlo formation from the island of busuanga in the north palawan block npb and from the guinlo on the main island of palawan are similar fail regional fold tests and have af demagnetization characteristics consistent with secondary magnetization their inclinations are statistically indistinguishable at a 95 significance level but variation in declination suggests differential local rotation about a vertical axis the paleolatitude is comparable to that of regions of pervasive cretaceous remagnetization in the south china borderland and may reflect similar remagnetization consistent with the npb s proposed south china origin

evaluating the evolution of the red river system based on in situ u pb dating and hf isotope analysis of zircons 1 the red river originates from sw china and se tibet and has a total length 1000 km in this study we present new u pb dating and hf isotopic analysis of zircon grains from both modern and paleoriver sands in order to constrain the provenance of the modern river and to decipher drainage evolution through time our data show that the yangtze and songpan garze blocks are the most important sources for sediment although this material is mostly reworked via younger sedimentary rocks in the upper reaches of the red river sands in the da river and to a lesser extent the lo river have zircon ages indicating that they are minor contributors to the net flow consistent with rock uplift which is strongest in the upper reaches of the red river rather than precipitation being the primary control on erosion sediments eroded from the metamorphic rocks along the red river fault zone appear to have made a greater contribution during the miocene zircon ages suggest that the red river flowed north of the day nui con voi in the middle late miocene the red river appears to have had a largely stable provenance since at least the late miocene upper miocene sedimentary rocks ne of the red river indicate the presence of a separate large river in the late miocene hf isotope data indicate that the irrawaddy river was never part of the red river system although we do not exclude the salween mekong and yangtze rivers from having been part of the red river any connection must have been pre middle miocene

cenozoic tectonics in the buruanga peninsula panay island central philippines as constrained by u pb 40ar 39ar and fission track thermochronometers abstract buruanga peninsula forms the westernmost part of panay island central philippines and is a part of the palawan continental terrane pct which was formerly attached to south eastern china it acted as the leading edge of the continental fragment and collided with the philippine mobile belt pmb followed by convergence beneath the latter dating of the collision is crucial for understanding the evolution of the archipelago samples collected from buruanga peninsula were dated using u pb 40 ar 39 ar and fission track dating ftd techniques to constrain the timing of the tectonic events related to the collision of the pmb with the pct these techniques have enabled us to obtain ages over a range of closure temperatures from about 700 c to about 110 c paleoproterozoic and permian zircon u pb ages from saboncogon formation emphasize derivation of the western part of buruanga peninsula from se china zircon and apatite fission track ages of 51 ma and 16 ma respectively constrain the exhumation of this formation the age data suggest tectonic events at 14 ma 11 12 ma and about 7 8 ma following intrusive activity at about 18 ma uplift and exhumation at 14 ma are thought to be the result of subduction of low density crustal rocks at 11 ma to be the result of isostatic uplift as a consequence of crustal thickening and at 8 ma to be due to the isostatic re equilibration of the sediments overlying the former suture hence collision is constrained to have started at about 14 15 ma and to have ended before 8 ma multi element patterns of the 18 ma patria diorite from buruanga peninsula show enrichment in lile rb sr and k and lree and depletion in hfse elements ti nb and ta similar to those from luzon volcanics and the volcanic rocks of negros island these arc signatures indicate a subduction related environment for the emplacement of this intrusive body and show that the diorite belongs to the pmb the age constraints of the present study neither support the concept of an early miocene collision nor the assumption of a late miocene collision thus have a significant bearing on the controversial issues regarding the evolution of the present day philippine archipelago

mesozoic terrane accretion in northeast china sikhote alin and japan regions abstract the nadanhada range in northeast china is composed of upper paleozoic limestone greenstone middle to late triassic bedded chert and middle jurassic siliceous shale these rocks are enclosed in post middle jurassic clastic rocks the lithologic association ages radiolarian assemblages and geologic structure of the nadanhada range are very similar to those of the tamba mino ashio terrane in southwest japan this indicates that the nadanhada range is the northern extension of the tamba mino ashio terrane mesozoic tectonostratigraphic terranes identified in northeast china sikhote alin and southwest japan are the khanka terrane a micro continent composed of precambrian metamorhic rocks and paleozoic to mesozoic sedimentary and volcanic covers the nadanhada western sikhote alin terrane a disrupted terrane composed of upper paleozoic to jurassic sedimentary rocks the eastern sikhote alin terrane a terrane composed mainly of early cretaceous clastics the tetyukhe terrane a disrupted terrane composed of upper paleozoic to early cretaceous sedimentary rocks the hida terrane a continent type stratigraphic terrane composed of precambrian and upper paleozoic basement covered with jurassic to cretaceous coarse clastics and the tamba mino ashio terrane a disrupted terrane composed of upper paleozoic to earliest cretaceous sedimentary rocks accretionary history of these terranes is discussed on the basis of paleomagnetic and paleobiogeographic data

late mesozoic compressional folds in dongsha waters the northern margin of the south china sea once considered as a component part of the cenozoic pearl river mouth basin prmb dongsha waters was found with distinct tectono stratigraphic style in which the upper structural layer comprises only thin usually 0 5 1 km sediments of mid miocene to quaternary whereas the lower layer consists of early cretaceous terrestrial jurassic marine and possibly triassic sedimentary rocks totaled 4 9 km thick the major sedimentary hiatus between them corresponds to the late cretaceous to mid miocene epoch well during the continental rifting to oceanic spreading stage faulting and magmatism during the opening of the south china sea are basically weak over the central part of dongsha waters where the crustal thickness is mostly around 25 km thick reflecting a relatively stable block all these indicate less influence exerted by the cenozoic rifting strikingly contrasting to the neighboring areas where thick rift to drift sediments have accumulated with the recognition of mesozoic strata in this and the previous study a relict mesozoic basin is proposed to be existed over dongsha waters and named as dongsha basin there are two generations late neogene and late jurassic to early cretaceous of compressions featuring seafloor and blind folds respectively the former presents only in few localities in east to dongsha island the later distributes widely as individuals in north and as trains in south they are characterized mostly by gentle growth folds inside which only a few minor upthrust faults with offsets in the order of a few tens to hundreds of meters the upthrust faults dipped mostly southeastward against to the northwestward subduction of paleo pacific as suggested in a previous study they featured more like back thrust growth tectonics formed a broad nne ssw trending belt oblique to the northern margin of the south china sea and thus are inferred to have been the far field impact of the late mesozoic subduction of the proto pacific c 2014 elsevier b v all rights reserved

the north west borneo trough abstract the north west borneo trough is bordered along its south east margin by a melange wedge that has been the subject of disagreement with insufficient discussion offshore palawan it has been interpreted as an accretionary prism that has been preserved in place when subduction ceased in the middle miocene it is unconformably overlain by undeformed upper miocene to holocene draping strata farther south west along the trough the seismically identical melange wedge has been named a major thrust sheet system which was assumed to have been thrust as a nappe north westwards over the autochthonous dangerous grounds terrane of attenuated continental crust of the south china sea passive margin the accretionary prism model is the simplest resulting in interpretation of the north west borneo trough as a fossil trench subduction was halted by the rifted and attenuated continental crust arriving at the benioff zone choking subduction and causing isostatic uplift of the western cordillera of sabah the subduction system therefore became a collision zone resulting in the term foredeep in which case the actual trench position remains obscure and somewhere towards the south east but shown in unrestrained geological cartoons enigmas remain in the palawan area of the philippines the trough position is bathymetrically obscure in places and its given position makes it impossible to derive the calamian micro continent from continental asia as required from its stratigraphy in the south west the trough terminates abruptly at the west baram line the trough contains several spectacular edifices formerly suggested to be volcanoes or mud volcanoes but herein shown to be carbonate build ups that were drowned indicating that the trough subsided too fast for build up continuation whereas post rift thermal subsidence of the dangerous grounds was slower allowing the spratly islands build ups to continue active

multi scale three dimensional characterization of iron particles in dusty olivine implications for paleomagnetism of chondritic meteorites dusty olivine olivine containing multiple sub micrometer inclusions of metallic iron in chondritic meteorites is considered an ideal carrier of paleomagnetic remanence capable of maintaining a faithful record of pre accretionary magnetization acquired during chondrule formation here we show how the magnetic architecture of a single dusty olivine grain from the semarkona ll3 0 ordinary chondrite meteorite can be fully characterized in three dimensions using a combination of focused ion beam nanotomography fib nt electron tomography and finite element micromagnetic modeling we present a three dimensional 3d volume reconstruction of a dusty olivine grain obtained by selective milling through a region of interest in a series of sequential 20 nm slices which are then imaged using scanning electron microscopy the data provide a quantitative description of the iron particle ensemble including the distribution of particle sizes shapes interparticle spacings and orientations iron particles are predominantly oblate ellipsoids with average radii 242 94 199 80 123 58 nm using analytical tem we observe that the particles nucleate on sub grain boundaries and are loosely arranged in a series of sheets parallel to 001 of the olivine host this is in agreement with the orientation data collected using the fib nt and highlights how the underlying texture of the dusty olivine is crystallographically constrained by the olivine host the shortest dimension of the particles is oriented normal to the sheets and their longest dimension is preferentially aligned within the sheets individual particle geometries are converted to a finite element mesh and used to perform micromagnetic simulations the majority of particles adopt a single vortex state with bulk spins that rotate around a central vortex core we observed no particles that are in a true single domain state the results of the micromagnetic simulations challenge some preconceived ideas about the remanence carrying properties of vortex states there is often not a simple predictive relationship between the major intermediate and minor axes of the particles and the remanence vector imparted in different fields although the orientation of the vortex core is determined largely by the ellipsoidal geometry i e parallel to the major axis for prolate ellipsoids and parallel to the minor axis for oblate ellipsoids the core and remanence vectors can sometimes lie at very large tens of degrees angles to the principal axes the subtle details of the morphology can control the overall remanence state leading in some cases to a dominant contribution from the bulk spins to the net remanence with profound implications for predicting the anisotropy of the sample the particles have very high switching fields several hundred millitesla demonstrating their high stability and suitability for paleointensity studies

tectono stratigraphic terranes and detachment faulting of the south china sea and sulu sea abstract geoscientific data acquired from the south china sea and sulu sea areas by bgr since 1977 are compiled and interpreted as comprehensive data sets together with available information of commercial wells and drillsites of the ocean drilling program odp generalized stratigraphy and lithology are discussed and correlated with the interpreted seismic profiles on the basis of the stratigraphic and structural analysis 5 main tectono stratigraphic terranes are defined for the south china sea and 4 main terranes for the sulu sea respectively the dangerous grounds reed bank palawan nw borneo trough and palawan island represent terranes of continental origin which developed on the proto china margin by uniform sense low angle simple shearing within the crust in late cretaceous to early paleocene this rift was abandoned and a new westward propagating rift system developed north of the dangerous grounds reed bank area from the middle eocene to the oligocene early miocene together with seafloor spreading in the south china sea basin the leading edge of the southward drifting continental terranes collided with the late cretaceous to early eocene subduction complex of the northernmost terrane of the proto sulu sea continuous convergence of these terranes back arc spreading creating the se sulu sea terrane and the assumed anti clockwise rotation of borneo are responsible for the complex collision compression structures of the sulu sea terranes including the formation of splinters of oceanic crust major right lateral wrench systems are nnw sse running up to 500 km long and cut across most of the identified terranes wrenching presumably ceased 12 to 16 myr ago

pre eocene synmetamorphic structure in the mindoro romblon palawan area west philippines and implications for the history of southeast asia the structure of the pre eocene rocks considered as the basement of the philippines has been investigated in the mindoro lubang romblon tablas sibuyan and north palawan areas in the former two areas the same pre eocene succession of units is recognized from top to bottom 1 a pre eocene olistostrome 2 an ophiolitic nappe 3 a schistose sequence pelites sandstones basic schists and marbles and 4 a gneissic unit the nature of the contact between the olistostrome and the underlying units is unclear but the ophiolite and the schistose sequence form two thrust sheets of oceanic origin thrust upon the gneissic unit that is considered a part of a continental basement called the west philippines block small scale structures show that the early deformation stage is characterized by a submeridian 0 n40 e lineation formed in greenschist to amphibolite facies conditions during the thrusting kinematic analysis show that the thrusting was from north to south in north palawan metamorphic rocks with similar microtectonic and kinematic characteristics are found they are overlain by a late jurassic olistostrome which is correlated with the olistostromes found in calamian north mindoro carabao and buruanga peninsula north panay the microstructural features and the presence of the olistostrome suggest that the north palawan mindoro tablas romblon sibuyan and carabao islands belong to the same north palawan block of hamilton 1979 which is a continental fragment rifted from asia in cenozoic times it is assumed that the western panay and zamboanga areas which are characterized by mesozoic ophiolites and metamorphic rocks also belong to the north palawan block all these islands experienced to some extent the same mesozoic geohistory the south verging thrusting is interpreted as the result of an oblique collision of the west philippines block with asia the contemporaneous left lateral strike slip faulting and the calc alkaline magmatism widespread along the chinese margin are also included in the geodynamic model