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1.
日本西南部的南海海槽是一个典型的俯冲系统,由菲律宾海板块向欧亚板块俯冲形成,其俯冲板片包含了九州-帕劳洋脊（KPR）、Kinan海山链、四国海盆和伊豆-小笠原岛弧（IBA）等多种地质单元。为了研究不同地质单元的板块俯冲效应,本文系统分析了南海海槽的地球物理和岩石地球化学特征。重力和热流特征显示南海海槽中部具有低的重力异常（-20–-40 mGal）和高的热流值（60–200 mW/m2）,而东西两侧的热流值（20–80 mW/m2）较低。地震模拟结果显示俯冲板块的地壳厚度为5–20 km。地球化学结果表明俯冲板块的下覆地幔成分从西到东逐渐亏损。无震洋脊（如KPR、Kian海山链和Zenisu洋脊）的俯冲是控制南海海槽俯冲效应的主要因素。首先,无震洋脊的俯冲可能使上覆板块发生变形,沿着增生楔前缘出现不规则的地形凹陷。其次,无震洋脊的俯冲是大型逆冲地震的止裂体,阻碍了南海海槽1944年Mw 8.1和1946年Mw 8.3地震破裂的传播。此外,KPR和热的、年轻的四国海盆的俯冲会导致俯冲板片熔融,在日本岛弧上出现埃达克质岩浆活动,并为斑岩铜金矿床提供成矿物质。地球物理和地球化学特征的差异表明尽管IBA已经和日本岛弧发生碰撞,但作为IBA的残留弧,KPR仍然处于俯冲阶段,与日本岛弧之间有明显的地形分界,呈现单向收敛的状态。  相似文献   

2.
Heat flow estimated from the gas hydrate layers on the landward slope of the Nankai Trough reveals that heat flow increases downslope toward the trench floor. This data plus six new heat flow values obtained by a conventional probe and two values available from DSDP drill holes give a fairly detailed heat flow distribution in the Nankai Trough area, when combined with the already existing data set. There appears to be a zonal pattern parallel to the trough axis, with a high heat flow zone on the floor of the trough that is quite anomalous for a subduction zone. It might be explained as a result of subduction of the hot portion of the Philippine Sea plate, i.e. the Shikoku Basin, and/or of more local effects such as heating due to intrusion of hot water from subducted sediments to shallow depth beneath the trough floor. Surface heat flow patterns landward of the trough were calculated for a simple thermal model of subduction. Perfect reproduction of the observed zonal pattern is difficult to achieve by the simple model, suggesting the necessity for further heat flow and other observations.  相似文献   

3.
We investigated the relationship between variations in the thermal conductivity of surface sediments and the topography in the Nankai subduction zone off Tokai, central Japan, the easternmost part of the Nankai subduction zone, which has an accretionary prism with varied topography. We analyzed sediment thermal conductivity data obtained from the trough floor and accretionary prism. Variations in the thermal conductivity of sediments were related to the topographic features formed by accretionary prism development. Thermal conductivities of 1.1?W/m?K were measured on the trough floor where thick terrigenous turbidites have been deposited. The thermal conductivity of Nankai Trough floor sediments decreases from northeast to southwest along the trough, probably because of the decreased grain size and/or changes in sediment mineral composition. High thermal conductivities (??1.0?W/m?K) were measured in fault scarps on the accretionary prism. A landward increase in these values on the prism may be explained by decreased porosity of the sediments attributable to tectonic deformation during accretionary prism development. At the base of the fault scarp of the frontal thrust, low thermal conductivities (<0.9?W/m?K) were measured, likely reflecting the high porosity of the talus deposits. Low thermal conductivity (0.9?W/m?K) was also measured in slope basins on the accretionary prism, likely also related to the high porosity of the sediments. Our results demonstrate that, for accurate heat flow measurement in an area of varied topography, the geothermal gradient and the thermal conductivity of the sediments must be measured within regions with similar topographic features.  相似文献   

4.
黄河三角洲地区第四纪海进与岸线变迁   总被引：13，自引：1，他引：13  
根据上百个钻孔的岩性岩相资料及数十个钻孔的微体古生物、地下水化学及土壤易溶盐等方面的分析资料,结合古地磁、~(14)C测年成果,讨论了黄河三角洲地区第四纪海进、海退特征及海进对地下咸水形成与分布的影响,勾划了全新世海进盛期此区的海岸线,讨论了全新世海岸线的变迁过程。  相似文献   

5.
Bottom currents in Nankai Trough and Sagami Trough   总被引：1，自引：0，他引：1  
Mean flows and velocity fluctuations are described from direct measurements of bottom currents made at three stations across Nankai Trough and two stations in Sagami Trough from May 1982 to May 1984. Aanderaa current meters were moored 7 m above the bottom. The observed mean flows indicate a counter-clockwise circulation in Nankai Trough with current speeds of 0.9–2.1 cm sec–1. The mean flows were larger on the slopes than on the flat bottom of the trough. The mean flows observed in Sagami Trough show an inflow into Sagami Bay which is considered to be a part of the Oyashio undercurrent from the north that flows along the eastern coast of Honshu. Velocity fluctuations with periods greater than 100 hr were less energetic in the troughs than those at a station west of Hachijo-jima Island. A highly energetic fluctuation with a period of 66.7 hr was observed on the northern slope of Sagami Trough in the velocity component parallel to the trough axis. A maximum current speed of 49 cm sec–1 was observed in Sagami Trough.This study was sponsored by the Ministry of Education, Science and Culture, Japan.  相似文献   

6.
The Mid-Polish Trough (MPT) is situated in the easternmost part of the Central European Basin System (CEBS) and stretches NW–SE across the Polish Basin. It was characterised by pronounced subsidence and thick sediment accumulation between the Permian and the Late Cretaceous. Late Cretaceous–early Paleogene basin inversion led to the formation of the Mid-Polish Swell (MPS). The study area is located within the Pomeranian segment of the MPT/MPS (NW Poland) and experienced up to 7 km Permian-Mesozoic subsidence. PetroMod 1-D modelling was performed on several well-sections in order to study Permian to recent burial-uplift evolution. The modelling was calibrated with new vitrinite reflectance (VRr) data and allowed to constrain the magnitude of uplift and related erosion as well as provided a first overview of the temperature history. The base of the studied Permian–Mesozoic successions attained maximum burial depths of 4800–5400 m before the onset of the inversion, less than in the axial trough area. The thickness of pre- and most probably also syn-inversion Upper Cretaceous deposits is estimated as 300 m. Erosion associated with inversion processes removed between 900 and 1400 m of the Mesozoic sediments, i.e. 1000–1500 m less than in the most inverted central part of the trough. VRr data suggest constant Permian–Mesozoic heat flows corresponding to present-day values (40–45 mW/m2). Apatite fission-track (AFT) ages modelled with the PetroMod module PetroTracks show a good fit with AFT ages directly measured on well samples, and further support the assumption of steady heat flow in the range 40–45 mW/m2. Palaeotemperatures appear to have decreased towards the East European Craton margin, which is compatible with the present day distribution of heat flow. Thermal history modelling shows a relatively simple Permian–Mesozoic heat flow pattern in the Pomeranian segment of the MPT. Such a scenario implies that the present-day heat flow distribution has not changed essentially since Mesozoic times.  相似文献   

7.
The Mid-Polish Trough (MPT) is situated in the easternmost part of the Central European Basin System (CEBS) and stretches NW–SE across the Polish Basin. It was characterised by pronounced subsidence and thick sediment accumulation between the Permian and the Late Cretaceous. Late Cretaceous–early Paleogene basin inversion led to the formation of the Mid-Polish Swell (MPS). The study area is located within the Pomeranian segment of the MPT/MPS (NW Poland) and experienced up to 7 km Permian-Mesozoic subsidence. PetroMod 1-D modelling was performed on several well-sections in order to study Permian to recent burial-uplift evolution. The modelling was calibrated with new vitrinite reflectance (VRr) data and allowed to constrain the magnitude of uplift and related erosion as well as provided a first overview of the temperature history. The base of the studied Permian–Mesozoic successions attained maximum burial depths of 4800–5400 m before the onset of the inversion, less than in the axial trough area. The thickness of pre- and most probably also syn-inversion Upper Cretaceous deposits is estimated as 300 m. Erosion associated with inversion processes removed between 900 and 1400 m of the Mesozoic sediments, i.e. 1000–1500 m less than in the most inverted central part of the trough. VRr data suggest constant Permian–Mesozoic heat flows corresponding to present-day values (40–45 mW/m2). Apatite fission-track (AFT) ages modelled with the PetroMod module PetroTracks show a good fit with AFT ages directly measured on well samples, and further support the assumption of steady heat flow in the range 40–45 mW/m2. Palaeotemperatures appear to have decreased towards the East European Craton margin, which is compatible with the present day distribution of heat flow. Thermal history modelling shows a relatively simple Permian–Mesozoic heat flow pattern in the Pomeranian segment of the MPT. Such a scenario implies that the present-day heat flow distribution has not changed essentially since Mesozoic times.  相似文献   

8.
Tectonically, the northwestern South China Sea （SCS） is located at the junction between three micro-plates, i.e., the Indochina, South China and Zhongsha-Xisha micro-plates, and involves three basins, i.e., the Yinggehai Basin, the Qiongdongnan Basin and Xisha Trough in the east, and the Zhongjiannan Basin in the south. Since the Pliocene （5.3 Ma）, the Yinggehai Basin has experienced repeated accelerating subsidence, high thermal fluid, and widely developing mud-rich overpressure chambers, abundant mud diapers and crust-mantle mixed CO2. While a large central canyon was developed in the Qiongdongnan Basin, new rift occurred in the Xisha ~rough. These characteristics demonstrate a single tectonic unit for the northwestern SCS, for which we have undertaken stress field modeling to understand its plate deformations and sedimen- tary responses. Our results demonstrate that an extension tectonic event occurred after 5.3 Ma in theYingge- hal-Qiongdongnan-Xisha trough area, which is characterized by thinner crust C〈16000 m）, half-graben or graben structural style and thicker sedimentary sequences （〉3 500 m）. A new rift system subsequently was developed in this area; this event was mainly driven by the combined effects of different movement veloc- ity and direction of the three micro-plates, and the far-field effect of the continental collision between the Indian Plate and the Tibetan Plateau, and subduction of the Pacific Plate underneath the Eurasian Plate.  相似文献   

9.
在东亚和东南亚第四系对比中,有关的几条界限,本文建议如后。采用Globorotalia truncatulinoides的初现位作为本区海相第四系的下界,其位置大致在古地磁Olduvai亚时的下界,时间约为距今1.9Ma。在南中国海、东海及沿岸地区,发现了以G.truncatulinoides的初现位为代表的一系列有意义的生物事件,如Pulleniatina finalis的初现位,Globigerinoides obliquus和Globoquadrina altispira的灭绝位,以及Globorotalia menardii和Pulleniatina obliquloculata壳体旋向的变化。此界限在东亚和东南亚也是相当稳定的。在陆相地层中,以泥河湾组为代表,狭义的泥河湾动物群(相当于晚维拉方动物群)所在地层的底界,其古地磁位置为Olduvai亚时的底界。以此作为陆相第四系的下界,与上述海相第四系底界一致。 以古地磁布容/松山界线作为中更新世和早更新世的界限,其年代为0.73MaB.P.。中国中更新世的标准地层周口店组,其底界恰为布容/松山的转换面,北京猿人的年代为0.60—0.23MaB.P.。在洛川黄土剖面上,布容/松山界线为古土壤S_7的底界。雷琼地区中更新统下部的北海组的底界也是布容/松山界线,所产的玻璃陨石的裂变径迹年龄为0.687—0.733MaB.P.。在黄海,布容/松山界线是第Ⅶ海侵层的顶界。通过岩石地层标志,以及动物群、古人  相似文献   

10.
Heat flow was measured on the Lomonosov Ridge during the 5th Chinese National Arctic Expedition in 2012. To derive the time-temperature curve, resistivity data were transformed to temperature by the resistivity- temperature program. Direct reading and linear regression methods were used to calculate the equilibrium temperature, which were regressed against the depth of the probes in sediment to derive the geothermal gradient. Then, heat flow was calculated as the product of geothermal gradient and thermal conductivity of sediments. The heat flow values on the basis of the two methods were similar （i.e., 67.27 mW/m2 and 63.99 mW/m2, respectively）. The results are consistent with the measurements carried out at adjacent sites. The age of the Lomonosov Ridge predicted by the heat flow-age model was 62 Ma, which is in accordance with the inference that the ridge was separated from Eurasia at about 60 Ma.  相似文献   

11.
Estimation of swell conditions in coastal regions is important for a variety of public, government, and research applications. Driving a model of the near-shore wave transformation from an offshore global swell model such as NOAA WaveWatch3 is an economical means to arrive at swell size estimates at particular locations of interest. Recently, some work (e.g. Browne et al. [Browne, M., Strauss, D., Castelle, B., Blumenstein, M., Tomlinson, R., 2006. Local swell estimation and prediction from a global wind-wave model. IEEE Geoscience and Remote Sensing Letters 3 (4), 462–466.]) has examined an artificial neural network (ANN) based, empirical approach to wave estimation. Here, we provide a comprehensive evaluation of two data driven approaches to estimating waves near-shore (linear and ANN), and also contrast these with a more traditional spectral wave simulation model (SWAN). Performance was assessed on data gathered from a total of 17 near-shore locations, with heterogenous geography and bathymetry, around the continent of Australia over a 7 month period. It was found that the ANNs out-performed SWAN and the non-linear architecture consistently out-performed the linear method. Variability in performance and differential performance with regard to geographical location could largely be explained in terms of the underlying complexity of the local wave transformation.  相似文献   

12.
At high bed shear stress sheet flows often occur in coastal waters in which high-concentration bedload sediments are transported in a thin layer near the bed. This paper firstly constructs a theoretical model (partial differential equations, PDEs) for the intense transport of non-cohesive bedload sediments by unidirectional currents and then seeks a special solution to the PDEs to determine the thickness of the bedload particle–water mixture, which could serve as the “reference height” that is often invoked in numerical computation and simulation of suspended sediment transport in turbulent flows. Moreover, a modified formula is presented to determine the “reference concentration”. Using a “uch” approach the present study derives a 1D formula for predicting bedload transport rate in sheet flows driven by asymmetric waves, with the help of a novel formula for evaluating wave friction factor. The new bedload formula can generically take into account slope angle (positive and negative), wash load concentration in the driving water flow and other factors that affect bedload transport rate. It compares well with measured data in a large-scale wave flume [Dohmen-Janssen, C.M., Hanes, D.M., 2002. Sheet flow dynamics under monochromatic non-breaking waves. Journal of Geophysical Research, 107(C10), 1301–1321], a large-scale oscillatory water tunnel [ Hassan, W.N., Ribberink, J.S., 2005. Transport processes of uniform and mixed sands in oscillatory sheet flow. Coastal Engineering, 52, 745–770] and in a swash zone of natural beach [Masselink, G., Hughes, M.G., 1998. Field investigation of sediment transport in the swash zone. Continental Shelf Research, 18, 1179–1199].  相似文献   

13.
The seismic stratigraphy and sedimentary architecture of the Amundsen Gulf Trough and adjacent slope, Canadian Beaufort Sea margin, are investigated using a grid of 2-D seismic reflection data. The inner-shelf of the Amundsen Gulf Trough is interpreted to be composed predominantly of exposed or near-surface bedrock, overlain by a spatially-discontinuous veneer of glacimarine to open-marine sediment. There is a seaward transition from exposed bedrock on the inner-shelf to a thick (up to 500 m) outer-shelf prograding wedge of acoustically semi-transparent sediment. Eight seismic sequences, divided into four megasequences, are described from the outer-shelf stratigraphy. Eight till sheets are identified from Megasequences A to C, providing evidence for at least eight Quaternary ice-stream advances through the Amundsen Gulf Trough to the shelf break. A trough-mouth fan with a minimum volume of about 10,000 km3 is present on the adjacent slope. The Amundsen Gulf ice stream probably represented the most northwesterly marine-terminating ice stream of the Laurentide Ice Sheet through much of the Quaternary, providing a major route for ice and sediment transfer to the Arctic Ocean. The youngest till sheet within the Amundsen Gulf Trough, Megasequence D, was probably deposited by a subsidiary ice stream, the Anderson ice stream, subsequent to retreat of the last, Late Wisconsinan Amundsen Gulf ice stream. This provides evidence of dynamic ice-sheet behaviour and the reorganisation of the northwest Laurentide Ice Sheet margin during the last deglaciation. A number of buried glacigenic landforms, including palaeo-shelf break gullies and a grounding-zone wedge with a volume of 90 km3, are described from the Amundsen Gulf Trough stratigraphy. Lateral grounding-zone wedges are identified at the northern and southern lateral margins of the Amundsen Gulf and M'Clure Strait troughs, respectively, and are interpreted to have been formed roughly contemporaneously by ice streams in Amundsen Gulf and M'Clure Strait.  相似文献   

14.
Migrated multichannel seismic reflection profiles and bathymetry from a 200 × 120 km area of the Nankai Trough inner slope reveal three physiographic-tectonic domains on the lowermost slope. Linear ridges demarking laterally-continuous hangingwall anticlines above ramps in a relatively simple imbricate stack of trench turbidites characterize the western domain. An imbricate fan underlies a relatively flat structural terrace in the east. Between these two domains lies a compound knoll (Minami Muroto Knoll) some 40 km long, opposite which the thrust front pushes some 10 km further seaward than is the case in the domains to east and west. In the western ‘linear-ridge’ domain previous DSDP drilling penetrated turbiditic trench fill uplifted in the lowermost thrust-fold terrace above a decollement within the underthrusting Shikoku Basin (oceanic plate) sequence. The Shikoku Basin sequence in the western domain is divided into an upper, poorly reflective, hemipelagic claystone unit and a lower, strongly reflective, unit comprising Pliocene turbidites. The lower unit is traceable intact up to c.20 km landward below the lower trench slope and in the better resolved profiles the decollement lies along the base of the claystone unit. A similar decollement within the Shikoku Basin sequence in the eastern domain is traceable up to c.22 km landward. A critical seismic record crossing the western part of Minami-Muroto Knoll shows that the decollement is traceable only 8 km landward to a point, under the steep slope at the front of the knoll, landward of which the subducting Shikoku basin sequence is apparently thickened by as much as twice. This thickening, occuring as it does immediately along-strike from a simple imbricate fan to the east of the knoll and a relatively simple imbricate stack to the west (both evidently involving no strata from the lower Shikoku Basin unit) we ascribe to underplating by formation of duplexes of Shikoku Basin strata. Strike-parallel extension, akin to that postulated for high structural levels in certain thrust belts, is caused by uplift of the knoll as a result either of the underplating, or segmentation of the subducting oceanic crust, or both: a normal fault throws to the west off the west flank of the knoll. It bounds a transverse, trough-like, slope-basin with at least 900 m of fill. Upslope from the knoll broadly slope-parallel normal faults cut, and pond, recent slope sediments. The most impressive is a listric growth fault which dips trenchward. Alternative explanations for these involve extensional collapse of this part of the prism resulting from the subduction of a topographic high, or a zone of selective underplating below the trenchward portion of Minami Murato Knoll.  相似文献   

15.
冲绳海槽地球动力学热模拟   总被引：3，自引：0，他引：3  
冲绳海槽属太平洋沟弧盆系,长1200km,宽100余公里,平均水深超过1000m,南部最深处2334m。实地地球物理考察表明,海槽全区布格重力异常和空间异常均呈北东向相对正高场值区,平均布格异常值为79.4m Gal,海槽南端可达160m Gal;空间异常平均值为60-100m Gal。根据重力反演计算的地壳厚度为14-20km,因此海槽比西侧大陆架和东侧岛弧的地売(30km)薄10-16km,但比正常洋壳的厚度仍大得多(金性春等,1984)。从海槽区的地震剖面图(Herman et al.,1978)可见海槽盆地东西两侧分别是倾向海槽中央的高角度正断层,表明海槽是张应力控制下的断陷带。地震折射资料(Lee,C.S.,1980)表明,冲绳海槽中央断裂下面的地幔深度约为15km。另外,海槽火山发育和地震频繁。近年来,地热测量结果更引起了研究人员的重视,海橧平均地表热流为151mW/㎡,个别地方如SON84-25-C和HF9-13,热流值分别高达1056mW/㎡和1258mW/㎡ (喻普之等,1992),如此高的热流值在全球地热数据中是罕见的。 冲绳海槽的地表热流、热结构及热演化问题目前在学术界颇引人注目,曾有人应用非稳态的二维热传导方程来计算海槽的热结构1),但这种不考虑对流效应的热传导方程不能模拟介质运动对热结构和热演化的影响,特别是在构造运动的速度大于1cm/a时, 其Peclet数一般大于1,这时介质运动所携带的热量远大于传导热,即对流项起主导作用。所以作者用非稳态的二维热传导——平流方程来模拟构造热演化。  相似文献   

16.
红河断裂带的新生代变形机制及莺歌海盆地的实验证据   总被引：30，自引：4，他引：30  
红河断裂带是印藏碰撞过程中，印支地块被顺时针旋转挤出的走滑变形带。莺歌海盆地发育于红河断裂带海上延伸带上。根据莺歌海盆地和相邻的NE向琼东南盆地在晚中新世前(5．5Ma B．P．)独立的构造发育和差异的沉降特点，认为红河断裂不可能穿越莺琼盆地界限向北东延伸，而越东断裂和中建南断裂很可能是红河断裂的延续。莺歌海盆地成盆机制的物理模拟结合红河断裂带陆上的变形特征、年代学证据与青藏高原隆升过程的研究，参考莺歌海盆地模拟过程中不同应力场下沉降中心的长轴方向，我们推断红河断裂带新生代的演化大致分4个阶段：(1)50-38Ma B．P．期间的缓慢平移运动；(2)38—25MaB．P．期间的快速左行走滑运动；(3)25—5Ma B．P．期间的左行走滑逐渐停止阶段；(4)5Ma B．P．后的右行走滑阶段。  相似文献   

17.
An extensive carbonate system in the Gulf of Papua (GoP), developed in the late Oligocene–middle Miocene, was buried by huge influx of siliciclastics originated from Papua New Guinea. Major episodes of siliciclastic influx in the carbonate system are related to tectonic activity in the fold and thrust belt during the Oligocene Peninsular Orogeny, late Miocene Central Range Orogeny, and late Pliocene renewed uplift and exhumation of peninsular region. Siliciclastics did not influence the carbonate deposition during the late Oligocene–middle Miocene, since they were accumulated in the Aure Trough, proximal foreland basin protecting the carbonate system. The most significant burial of the carbonate system started during the late Miocene–early Pliocene in the result of the Central Range Orogeny. However, the largest influx was related to the renewed uplift of the Papuan Peninsula during the early late Pliocene. The shelf edge prograded ∼150 km and formed more than 80% of the modern shelf. This high siliciclastic influx was also enhanced by the “mid” Pliocene global warmth period and intensified East Asian monsoons at 3.6–2.9 Ma. Although many publications exist on carbonate–siliciclastic mixing in different depositional environments, this study helps understand the carbonate–siliciclastic interactions in space and time, especially at basinal scale, and during different intervals of the carbonate system burial by siliciclastic sediments.  相似文献   

18.
本文利用数值模拟技术重现了1707年宝永地震海啸的传播过程,定量分析了我国东海沿岸海啸时空分布特征。计算结果表明,地震发生2.5小时后海啸波传至东海陆架,震后6小时浙江沿海地区遭到海啸的袭击,沿岸最大海啸波高为0.8米。通过海啸波在东海大陆架传播时海底地形与波幅的关系,研究分析了东海陆架缓变地形下海啸放大效应,为及时判断沿海可能的海啸强度和受灾程度提供了便捷的估算方法。此外,本文还评估了南海海槽发生极端地震时,中国东海沿岸的海啸危险性,为东海区域针对日本南海海槽进行海啸预警和减灾评估提供定量科学的参考。  相似文献   

19.
One possible approach to estimating the time interval between large-scale Tōnankai (Tōkai) and Nankai earthquakes on the Japan arc is sequential assimilation of crustal deformation data. We conducted numerical modeling of sequential assimilation using surface deformation calculated from earthquake generation cycle simulations along the Nankai Trough. To account for observation noise, we used measured ocean bottom pressure gauge data, excluding tidal modulation, from a station on the ocean bottom cable network Dense Oceanfloor Network System for Earthquakes and Tsunamis in the Kumano basin. We used sequential importance sampling as our data assimilation method. We found that as the amount of data increased, the estimated time interval between the Tōnankai and Nankai earthquakes approached the “true” observed interval. In addition, the noise in the pressure gauge data was sufficiently small that simulated crustal deformation patterns could be distinguished for different time intervals.  相似文献   

20.
Accurate measurement of seawater pH has long been sought by marine chemists (for example: [Dickson, A.G. 1993a. The measurement of sea water pH. Marine Chemistry, 44, 131–142, Dickson, A.G. 1993b. pH buffers for sea water media based on the total hydrogen ion concentration scale. Deep-Sea Research, 40, 107–118; Zhang, 1996; Tapp, M., Hunter, K.A., Currie, K. and Macaskill, B. 2000. Apparatus of continuous-flow underway spectrophotometric measurement of surface water pH. Marine Chemistry 72(2–4), 193–202; Friis, K., Koetzinger, A., Wallace, D.W.R. 2004. Spectrophotometric pH measurement in the ocean: Requirements, design and testing of an autonomous charge-coupled device detector system. Limnology and Oceanography: Methods 2, 126–136]. Recently, such attempts have taken on greater significance as anthropogenic carbon dioxide emissions may create rapidly changing oceanic pH. Spectrophotometric techniques have been accepted generally as the best for determination of seawater pH. Here we report a new technique using thymol blue as the indicator dye and fitting the entire spectrum from 400 to 900 nm rather than measuring the absorbance values at only two or three points in the spectrum. This full-spectrum modelling enables a reduction in signal to noise over other techniques. In the laboratory, we find with seawater samples a pH precision increase of five-fold “within” a sample and seven-fold “between” samples when comparing the full spectrum to the three-point method of analysis [Zhang, H., Byrne, R.H. 1996. Spectrophotometric pH measurements of surface seawater at in-situ conditions: absorbance and protonation behaviour of thymol blue. Marine Chemistry 52, 17–25].  相似文献   

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