A backarc system represents an important geological response to the nature of the oceanic lithosphere and the mantle dynamics along a plate boundary e. The shikoku basin sb, which is a back arc basin formed through arc rifting, is located to the west of the ra. The tectonics and the tertiary structural history of the central sumatra backarc basin in the p. Backarc basins form because the subduction of old oceanic lithosphere may make the volcanic arc move toward the trench and produce an extensional basin behind the arc 2 necessary steps in the formation of a volcanic arc. The mariana trough is one of the most wellknown back arc basins in the world.
Pdf the relationship between subduction and backarc spreading has been well known since the early days of plate tectonics. Surface and subsurface expressions of folds and faults suggest that the basin experienced northnorthwestdirected. Caldera ce cinder cone cirque composite volcano coulee crust cryptodome cumulovolcano. Backarc basin, submarine basin that forms behind an island arc. Permiantriassic backarc basin development in response to. Backarc deformation regime is mostly controlled by the upper plate absolute motion relative to a partly anchored. Dacite debris avalanche debris dam deformation diamict dike directed blast doas dome drainage. Backarc basalts in many respects marginal basin basalts mbb are similar to normal midocean ridge basalts ntype morb. Media in category back arc basins the following 7 files are in this category, out of 7 total.
As subduction progresses, the island arc and the backarc basin may deform, and foldthrust structures. It is pointed out that the conditions required for the occurrence of this kind of mechanism may be recognized in most of the tectonic contexts where back arc basins developed in. Arc concrete basin please allow 24 weeks for production shipped from gold coast warehouse order now for free shipping australia wide a true statement piece handcrafted by concrete artisans, the arc basin is sleek, simple and inspiring. They are found at some convergent plate boundaries, presently concentrated in the western pacific ocean. Caltex pacific indonesia area of operations, situated largely between the bila river to the north and the kampar river to the south, are. Abstract the salin subbasin of myanmar part of the larger central basin is a forearcbackarc basin couplet situated between an oblique subduction zone to the west and a major rightlateral strikeslip fault to the east. Chemical systematics and hydrous melting of the mantle in backarc basins c. Sedimentation in backarc basins can be very varied, ranging from pelagic through turbidites to alluvial fans, although volcaniclastics see clast are common. Magma genesis and mantle heterogeneity in the manus back. The chilas complex is a 40 wide and 300 long composite plutonic body exposed in the central part of kohistan island arc, which formed first as intraoceanic island arc in the neotethyan oceanic crust and later transformed into andeantype continental margin after the closure of backarc basin. This petroleum system analysis of the tertiary ulleung basin offshore south korea is part of the korea national oil cooperation knoc active exploration program. Backarc basin article about backarc basin by the free. Clustering of arc volcanoes caused by temperature perturbations in the backarc mantle. Ar ages of south sakhalin volcanic rocks that back.
Petrology and geochemistry of back arc basin basalts of the five dives sampled lavas associated with extinct and active hydrothermal chimney fields mir dive sites 2226 and 2231 respectively. Pdf we suggest a more rigorous approach to paleogeodynamic reconstructions of the sayanbaikal. The understanding of the messinian salinity crisis msc as a mediterranean basinwide event requires an improved knowledge of the stratigraphy in the deep basins and continental margins e. Petroleum system analysis for a backarc basin offshore. Any theory for the genesis of backarc basins must account for this fact. Unique geochemistry of submarine hydrothermal fluids from arcbackarc settings of the western pacific. The backarc region is the area behind a volcanic arc. In continental arcs the backarc region is part of continental platform, either dry land or forming shallow marine basins. New species of scale worms polychaeta, polynoidae from. This geologic formation is located in the western region of the pacific ocean, where it is surrounded by the inactive west mariana ridge and the stillactive mariana volcanic arc to the east.
Backarc basins by fer nan d o m arti n ez, kyo ko o ki n o, ya s u h i ko o h a r a, a n n a lo u i s e r e y s e n b a c h, and. Smith, free software helps map and display data, eos. Pdf the compositions of backarc basin basalts babb can usefully be viewed as products of four. North sumatera basin is a backarc basin that occupies an area of 60,0000 sq. Backarc basins tectonics and magmatism brian taylor springer. Most of them result from tensional forces caused by oceanic trench rollback the oceanic trench is wandering in the seafloor direction and the collapse of the edge of the continent. Indian ocean hot spot reference frame oneill et al. Seismic imaging of late miocene messinian evaporites.
The composition of backarc basin lower crust and upper. Manus basin the spreading axes of the manus basin also show a systematic variation from arclike to morblike lava compositions withincreasing distance away from the new britain arc 37, though in this case gps measurements. Comparison of spreading processes between backarc basin and midocean ridge systems ii. Such basins are typically found along the western margin of the pacific ocean near the convergence of two tectonic plates. The subduction of old oceanic lithosphere may make the volcanic arc move toward the trench and produce an extensional backarc basin behind the arc which type of plate boundary is associated with most of earths major mountain belts. Sedimentary, volcanic, and tectonic processes of the central. Problems unique to the spreading process in backarc basins 5. Abstract the mariana trough is an active backarc basin, with the rift propagating northward ahead of. However, backarc basins differ from midocean ridges in several aspects, mainly. Sec 0 figure 5 seismic reflection, gravity and magnetic anomaly profiles l3 crossing the northern part of the okinawa trough. Subduction zones and island arcs university of leicester. The process of backarc basin formation appears to be inactive at present in some arcs as in the case of the japan sea, whereas others are believed to have an actively opening backarc basin, for example, the m ariana trough karig, 1971a. The composition of backarc basin lower crust and upper mantle in.
In this paper we present new major and trace element and isotopic data on lavas from the manus basin, a backarc basin behind the new britain island arc in papua new guinea fig. The basin displays only one producing gas condensate field and several gascondensate shows. Okinawa trough backarc basin early tectonic and magmatic evolution. The lavas are composed of basicintermediate and intermediateacidic subgroups that can be related by intraformation fractional crystallization. Backarc basins are sites of significant hydrothermal activity, and the deepsea vents that occur in these regions often harbour diverse biological communities. Arc concrete basin concrete nation ship australia wide. Various convective systems have been postulated to explain extension, which is oriented parallel to the compression in a. The eastern lau spreading centre, located on the lau backarc basin hydrothermal vent system between fiji and tonga, is a focus site of the ridge 2000.
In island volcanic arcs it consists of backarc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs. This last characteristic is interesting because it occurs in all backarc basins, despite widely varying ree patterns in associated island arcs. However during the early stages of backarc spreading, when the uprising mantle diapir splits the volcanic arc, the basalt magmas are derived from the subarc mantle. The relationship between subduction and back arc spreading has been well known since the early days of plate tectonics. Trace element and hf radiogenic isotope data reveal that the mantle. Deep structural graben are found in a region of low heat flow, and we interpret these to manifest a low. Our results suggest that backarc basin formation is always preceded by an absolute motion of. Due to the lack of lithological information from scientific and industrial wells, improvement of seismic imaging is currently the key element used to study the msc stratigraphy in the. Back arc basins are geologic basins, submarine features associated with island arcs and subduction zones. Junggar, tarim, and qaidam became inland basins with continental sedimentation after their communications to open sea were severed by the rising mountain chains. March 1979, backarc opening and the mode of subduction pdf. Samples from the arcproximal and shallow southeast ridges ser, have the highest bala and. The northern part of the trough is now rifting, with extension accommodated by combined stretching and igneous intrusion.
Evolution of faulting and volcanism in a backarc basin. Two suture zones, i the northern suture mkt and the southern suture mmt mark tectonic. To elucidate the origin of the kurile basin, the most direct approach is to study volcanic rocks that form in the back. The island arc 1996 5, 354372 research article the composition of backarc basin lower crust and upper mantle in the mariana trough. Active spreading ridges in the north fiji basin range from welldeveloped stable ridges where largescale mantle upwelling is in progress to protoridges where spreading is incipient. In island volcanic arcs it consists of backarc basins of oceanic crust with. The yakuno ophiolite in southwest japan is considered to have been obducted by the collision between an intraoceanic islandarcbackarc basin intraoiabab system and the east asian continent during the late paleozoic. The spreading axes of the manus basin also show a systematic variation from arclike to morblike lava compositions with increasing distance away from the new britain arc, though in this case gps measurements indicate that the segments closest to the arc are spreading the fastest, 5145 mmyr. Back arc basins are sites of significant hydrothermal activity, and the deepsea vents that occur in these regions often harbour diverse biological communities. Isostatic basin subsidence permitted the accumulation of thick mesozoic and paleogene sediments before tectonic rejuvenation along neogene faults.
Hydrocarbon exploration history began in the late 19 th century. Structural variations of arc crusts and rifted margins in. Backarc opening and the mode of subduction caltech authors. The okinawa trough ot is a curved backarc basin located northwest of. The cretaceous blue mountain inlier of eastern jamaica contains the bellevue lavas, which represent a mid to late campanian backarc basin succession of tholeiitic volcanic rocks. The sb margins might have clues to understanding the arc evolution brought about by crustal rifting. Published by the american geophysical union as part of the maurice ewing series, volume 1.
Backarc basins are extensional basins formed behind subduction zones by rifting vol canic arcs and. Plate motions, slab dynamics and backarc deformation. However, the reasons why back arc basins are associated with some subduction. Tell a friend about us, add a link to this page, or visit the webmasters page for free fun content. Manus basin the spreading axes of the manus basin also show a systematic variation from arc like to morblike lava compositions withincreasing distance away from the new britain arc 37, though in this case gps measurements. In this view, subduction and back arc extension are not causally linked one to the other, but rather represent simultaneous effects of the lateral migration of the arc. Backarc basin basalt basaltic andesite base surge batholith benchmark bishop tuff block and ash flow bomb breadcrust bomb. Petrology and geochemistry of backarc basin basalts from. New sims shrimp zircon upb determinations for amphibolite and metagabbro of bab origin within the yakuno ophiolite yield ages of 293. Mark harrison center for lithospheric studies, university of texas at dallas, richardson tx 750830688, usa. View notes backarc basins from epse 350 at mcgill university. A three day symposium was held in honor of the late maurice ewing at arden house, harriman, new york on. We find that backarc basins develop when the age of subducting normal oceanic lithosphere is greater than 55 million years.