University of Liverpool
School of Environmental Sciences
The storage and analysis of large amounts of time-varying spatial and aspatial data is becoming an important feature of many application domains. This has fuelled the need for spatio-temporal extensions to data models and their associated... more
The storage and analysis of large amounts of time-varying spatial and aspatial data is becoming an important feature of many application domains. This has fuelled the need for spatio-temporal extensions to data models and their associated querying facilities. To date, much of this work has focused on the relational data model, with object data models receiving far less consideration. Where descriptions of such object models do exist, these models fail to fully integrate their spatial, aspatial and temporal dimensions into a uniform and coherent model. In addition, there is currently a lack of systems which build upon these models to produce database architectures that address the broad spectrum of issues related to the delivery of a fully functional spatio-temporal DBMS. This paper presents a foundation for the development of such a system, called Tripod, by describing a spatio-historical object model based on a specialized mechanism, called a history, for maintaining knowledge about entities that change over time. Key features of the resulting model include: (i) consistent representations of primitive spatial and timestamp types; (ii) a component-based design in which spatial, timestamp and historical extensions are formalized incrementally, for subsequent use together or separately; (iii) compatibility with mainstream query processing frameworks for object databases; and (iv) the integration of the spatio-temporal proposal with the ODMG object database standard. The paper presents a comprehensive formal characterization of the model and illustrates its capabilities in a crime data management application. It is also shown how the model can be programmed using an extension to the ODMG language bindings. The model and language bindings have been fully implemented.
The Rodinia reconstruction of the Neoproterozoic Supercontinent has dominated discussion of the late Precambrian Earth for the past decade and originated from correlation of sedimentary successions between western North America and... more
The Rodinia reconstruction of the Neoproterozoic Supercontinent has dominated discussion of the late Precambrian Earth for the past decade and originated from correlation of sedimentary successions between western North America and eastern Australia. Subsequent developments have sited other blocks according to a distribution of V1100 Ma orogenic belts with break-up involving a putative breakout of Laurentia and rapid reassembly of continent crust to produce Gondwana by early Phanerozoic times. The Rodinia reconstruction poses several serious difficulties, including: (a) absence of palaeomagnetic correlation after V730 Ma which requires early fragmentation of continental crust although geological evidence for this event is concentrated more than 150 Ma later near the Cambrian boundary, and (b) the familiar reconstruction of Gondwana is only achieved by exceptional continental motions largely unsupported by evidence for ocean consumption. Since the geological evidence used to derive Rodinia is non-unique, palaeomagnetic data must be used to evaluate its geometrical predictions. Data for the interval V1150^500 Ma are used here to test the Rodinia model and compare it with an alternative model yielding a symmetrical crescent-shaped analogue of Pangaea (Palaeopangaea). Rodinia critically fails the test by requiring Antarctica to occupy the location of a quasi-integral Africa, whilst Australia and South America were much closer to their Gondwana configurations around Africa than implied by Rodinia. Palaeopangaea appears to satisfy palaeomagnetic constraints whilst surmounting geological difficulties posed by Rodinia. The relative motions needed to produce Gondwana are then relatively small, achieved largely by sinistral transpression, and consistent with features of Pan-African orogenesis; continental dispersal did not occur until the Neoproterozoic^Cambrian boundary. Analogies between Palaeopangaea and (Neo)pangaea imply that supercontinents are not chaotic agglomerations of continental crust but form by episodic coupling of upper and lower mantle convection leading to conformity with the geoid. ß
Magnetostratigraphic and rock magnetic results from 1006 horizons in Paleogene and Neogene sediments between the upper Kumugeliemu Formation and the base of the Kuche Formation within the Kuche Depression of the Tarim Basin, NW China, are... more
Magnetostratigraphic and rock magnetic results from 1006 horizons in Paleogene and Neogene sediments between the upper Kumugeliemu Formation and the base of the Kuche Formation within the Kuche Depression of the Tarim Basin, NW China, are used to evaluate postcollisional uplift and deformation in the Tian Shan Range. Characteristic remanences with both normal and reversed polarity were isolated by thermal demagnetization, generally between 300 and 690°C, and a composite magnetostratigraphy is constructed from data at 969 accepted levels correlating with polarity chrons C12n to C3r dated between ∼ 31.0 and ∼ 5.5 Ma on the CK95 geomagnetic polarity time scale. Observed height-dependent changes of rock magnetic parameters (k m and AMS ellipsoid parameters) indicate that these sediments were influenced by weak deformation with the succession accumulated before ∼ 15 Ma recording the effects of compressive deformation. This finding, together with two substantial increases in accumulation rate at ∼16-17 and ∼ 7 Ma, define a framework for Cenozoic uplift and deformation of the Tian Shan Range. We argue that thrusting in the south of the range was probably initiated at ∼ 20 Ma and followed by rapid uplift at ∼ 16-17 Ma. On the assumption that sediment accumulation in western China was still predominately tectonically controlled at ∼ 7 Ma, another later pulse of rapid uplift with a much larger regional influence is also recognized in the Tian Shan. The Kuche Depression was subjected to two postcollisional phases of rotational deformation with clockwise rotation prior to ∼12 Ma (∼ 1.36°/Ma) succeeded by counterclockwise rotation (at ∼1.64°/Ma) after ∼ 12 Ma and possibly continuing to the present day. This rotational deformation is not temporally related to the history of basin formation resolved from the magnetostratigraphy and may be linked to block interactions with adjoining terranes.
A combined paleomagnetic and geochronological study is reported of Paleogene basalt lavas and an intercalated red bed succession, comprising a minimum of 14 basalt flows and 10 red bed horizons in the Tuoyun Basin of the southwest Tian... more
A combined paleomagnetic and geochronological study is reported of Paleogene basalt lavas and an intercalated red bed succession, comprising a minimum of 14 basalt flows and 10 red bed horizons in the Tuoyun Basin of the southwest Tian Shan Range, China. Two basalt matrix samples yield 40 Ar / 39 Ar isochron ages of 58.5 F 1.3 Ma (2r, MSWD = 0.9) and 60.4 F 1.3 Ma (2r, MSWD = 1.7). These compare well with a previously published K-Ar dilution age of 61.7 F 2.3 Ma for comparable Paleogene basalts and confirm that the younger pulse of magmatism in this basin is represented by both intrusive and extrusive activity. Demagnetization and component analysis identify a stable characteristic remanence (ChRM) with predominantly reversed polarity following removal of secondary remanence by peak demagnetization steps below 250-350 8C or 5 mT. Rock magnetic analysis identifies pseudo-single domain magnetite or titanomagnetite as carriers. The stable ChRM passes a fold test; it was probably acquired at the time of lava emplacement. Results from the bulk of the collection imply that paleomagnetic data from the upper and lower (~115 Ma) basalt series in the Tuoyun Basin are not distinguishable at the 95% significance level and indicate that this tectonic domain remained essentially stationary with respect to the Earth's spin axis for~50 Ma prior to onset of the India/Asia collision in early Eocene times. It is therefore probable that no paleomagnetically detectable crustal shortening occurred in the southwest Tian Shan prior to collision. Paleomagnetic data sets from the Tuoyun Basin also show that little or no paleolatitude difference is present between the Tian Shan and the reference latitude of Eurasia at~60 Ma. This supports previous evidence suggesting that central Asian blocks in the vicinity of the Tian Shan are unlikely to have experienced appreciable northward convergence relative to Eurasia since onset of the India/Asia collision and initiation of the Himalaya. D
In the Turkish sector of the Afro-Eurasian collision zone, continuing northward motion of the Arabian promontory is extruding the Anatolian region to the west. Although the East Anatolian Fault Zone (EAFZ) is recognized as the southern... more
In the Turkish sector of the Afro-Eurasian collision zone, continuing northward motion of the Arabian promontory is extruding the Anatolian region to the west. Although the East Anatolian Fault Zone (EAFZ) is recognized as the southern boundary of this tectonic escape, distributed deformation is occurring across a broad zone extending for at least 300 km to the northwest, which includes a number of major dextral and sinistral fault lineaments. The longest of these lineaments is the Ecemi~ Fault Zone, although the longterm significance of deformation, and specifically strike-slip, across this zone is disputed. This zone is also the locus of major volcanic activity in the Kayseri region. The present paper reports a palaeomagnetic study of young (1-2 Ma) lava flows which has aimed to identify recent block rotations resulting from regional deformation in this region. Rock magnetism shows the lavas to be dominated by low-Ti magnetite assemblages of primary cooling related origin. Although grain properties are predominantly multidomain, significant fractions of single domains are always present and responsible for a stable thermoremanence of normal and reversed polarity. Whilst group mean directions show that the blocks in this sector of Anatolia show the typical counterclockwise rotation resulting from tectonic escape, in this case by c. 10 ° during the last 1 Ma, larger differential rotations in both senses are identified across the Sultansazh~i Depression. Comparable differential rotations recorded by the 2.8 + 0.2 Ma incesu Ignimbrite have resulted from the pull-apart in this sector of the Ecemi~ Zone which has accommodated emplacement of the Erciyes volcanic centre since the termination of ignimbrite activity. Within the wedge-shaped terrane confined between the EAFZ in the south and the North Anatolian Fault Zone in the north, the degree of counterclockwise rotation during tectonic escape within the last 2-3 Ma has diminished from c. 25 ° in the east to c. 10 ° towards the southwest. This corresponds to a transition from highly strained to a less-strained lithosphere as the width of the semi-plastic Anatolian terranes confined between the Arabian-Eurasian pincer broadens out to the west.
The pol~~tamo~hic terrain in the Darong-Huai'an region of the North China Shield records two metamorphic CM1 and M,) and associated defo~ational CD,--D, and DJ episodes in granulite facies. The magnetic fabric is dominated by the D,... more
The pol~~tamo~hic terrain in the Darong-Huai'an region of the North China Shield records two metamorphic CM1 and M,) and associated defo~ational CD,--D, and DJ episodes in granulite facies. The magnetic fabric is dominated by the D, foliation imparted by emplacement of allochthonous cover rocks onto basement during compression and subsequent collapse and uplift. Magnetite is present in four generations as: (1) discrete grains; (2) exsolution lamellae in mafic minerals; (3) corona rims formed during regional decompression; and (4) a filling of microfractures. It is the dominant ferromagnetic phase and carries a stable high blocking temperature remanence of dual polarity linked to magnetite grain sizes and shapes of generations (21 to (4). Remanence was acquired during later stages of uplift and cooling after the M, metamorphism and D, deformation and during rapid decompression. A NE to NW migration of the palaeofield direction during this time is identified. Palaeomagnetic directions are not constrained to lineation in the older magnetic anisotropy but lie close to the dominant D, foliation. Although no satisfactory methods presently exist for correcting remanence for anisotropy, qualitative considerations from petrology and comparisons between sites of contrasting AMS fabric suggest that palaeodirections are not prominently deflected into the D, plane. The pole positions define a continuous swathe plotting between SO"E, 20"s and 170"E, 35"s summarised by group mean poles Al Gl"E, 2O"S, dp/dm = 8/W), A2 @O"E, 339, dp/dm = 6/11"), A3 (106"E, 48"S, dp/dm = 7/13') and A4 (164"E, 40'S, dp/dm = 11/21"). They are assigned to the interval ea.
of marginal syenites and fractionated rocks of the Ili-/ff^V UyJlt. maussaq intrusion, South Greenland. Bull. geol. Soc. Denmark, vol. 25, pp. 89-97. Copenjj "S hagen, December, 20th 1976.
- by John Piper
- •
The Taurides, the southernmost of the three major tectonic domains that constitute present-day Turkey, were emplaced following consumption of the Tethyan Ocean in Late Mesozoic to mid-Tertiary times. They are generally assigned an origin... more
The Taurides, the southernmost of the three major tectonic domains that constitute present-day Turkey, were emplaced following consumption of the Tethyan Ocean in Late Mesozoic to mid-Tertiary times. They are generally assigned an origin at the northern perimeter of Gondwana. To refine palaeogeographic control we have investigated the palaeomagnetism of a range of Jurassic rocks. Forty-nine samples of Upper Jurassic limestones preserve a dual polarity remanence (D/I ¼ 303/ À 9 , 95 ¼ 6 ) interpreted as a primary magnetization acquired close to the equator and rotated during emplacement of the Taurides. Results from mid-Jurassic dolerites confirm a low palaeolatitude for the Tauride Platform during Jurassic times at the Afro-Arabian sector of Gondwana. Approximately 4000 km of Tethyan closure subsequently occurred between Late Jurassic and Eocene times. Although related Upper Jurassic limestones and Liassic redbeds preserve a sporadic record of similar remanence, the dominant signature in these latter rocks is an overprint of probable mid-Miocene age, probably acquired during a single polarity chron and imparted by migration of a fluid front during nappe loading. This is now rotated consistently anticlockwise by c. 30 and conforms to results of previous studies recording bulk Neogene rotation of the Isparta region following Lycian nappe emplacement. The regional distribution of this overprint implies that the Isparta Angle (IA) has been subject to only small additional closure (< 10 ) since Late Miocene time. A smaller amount (c. 6 ) of clockwise rotation within the IA since Early Pliocene times is associated with an ongoing extensional regime and reflects an expanding curvature of the Tauride arc produced by southwestward extrusion of the Anatolian collage as a result of continuing northward motion of Afro-Arabia.
Travertine, the product of incremental growth of inorganic carbonate, is potentially a high-resolution recorder of geomagnetic palaeosecular variation (PSV) when it incorporates small amounts of ferromagnetic material. It grows most... more
Travertine, the product of incremental growth of inorganic carbonate, is potentially a high-resolution recorder of geomagnetic palaeosecular variation (PSV) when it incorporates small amounts of ferromagnetic material. It grows most regularly in regions of neotectonic activity where geothermal waters feed into extensional fissures and deposit successive layers of carbonate as fissure travertine. The same waters spill out onto the surface to deposit bedded travertine which may incorporate wind blown dust including ferromagnetic particles. Tectonic travertine deposits are linked to earthquake activity because the geothermal reservoirs are reset and activated by earthquake fracturing but tend to become sealed up by carbonate deposition between events. This study investigates whether sequential deposition can identify cycles of PSV and provide a means of estimating rates of travertine growth and earthquake frequency. The palaeomagnetic record in three travertine fissures from the Sıcak Ç ermik geothermal field in Central Anatolia and nearby bedded travertines dated up to 360,000 years in age (U-Th) are investigated to evaluate magnetic properties and relate the geomagnetic signature to earthquake-induced layering.
Travertine, the product of incremental growth of inorganic carbonate, is potentially a high-resolution recorder of geomagnetic palaeosecular variation (PSV) when it incorporates small amounts of ferromagnetic material. It grows most... more
Travertine, the product of incremental growth of inorganic carbonate, is potentially a high-resolution recorder of geomagnetic palaeosecular variation (PSV) when it incorporates small amounts of ferromagnetic material. It grows most regularly in regions of neotectonic activity where geothermal waters feed into extensional fissures and deposit successive layers of carbonate as fissure travertine. The same waters spill out onto the surface to deposit bedded travertine which may incorporate wind blown dust including ferromagnetic particles. Tectonic travertine deposits are linked to earthquake activity because the geothermal reservoirs are reset and activated by earthquake fracturing but tend to become sealed up by carbonate deposition between events. This study investigates whether sequential deposition can identify cycles of PSV and provide a means of estimating rates of travertine growth and earthquake frequency. The palaeomagnetic record in three travertine fissures from the Sıcak Çermik geothermal field in Central Anatolia and nearby bedded travertines dated up to 360,000 years in age (U-Th) are investigated to evaluate magnetic properties and relate the geomagnetic signature to earthquake-induced layering. Sequential sampling of bedded travertine from the margins (earliest deposition) to centres of fissures (last deposition) identifies directional migrations reminiscent of PSV. Thermal demagnetisation shows that goethite pigment is not a significant remanence carrier; instead hematite, and more rarely magnetite, is the carrier. Magnetic susceptibility of fissure travertine is proportional to the calcite:aragonite ratio. Two-frequency susceptibility analysis identifies a ferromagnetic content in bedded travertine dominated by fine superparamagnetic grain sizes whereas the fissure travertine has mostly single and multidomain grain sizes, a difference interpreted to reflect contrasting energies of the two environments plus atmospheric input in the bedded travertine. Fissure travertine possesses strong lineated anisotropy of magnetic susceptibility (AMS), with horizontal kmax axes oriented along the fissure axes and kint and kmin distributed within the orthogonal plane; this is explained by rolling of ferromagnetic grains up the side of the fissure during repeated water ejection until fixed by the host carbonate precipitation. In contrast bedded travertine has low magnitude AMS with near neutral ellipsoid shapes controlled by settling of grains during weak outflow from the axis of the fissure ridge. The source of the magnetic minerals in the fissure travertine is probably in material washed down by meteoric waters from the local terra rossa soil and concentrations of these minerals (and hence magnetic susceptibility) could be a signature of pluvial environments. Fissure travertine is a reliable recorder of the ambient field when layered although bedded travertine is found to exhibit inclination shallowing. On the assumption that PSV cycles record periods of 1-2 ky, layering in the travertine identifies resetting of the geothermal system by earthquakes every 50-100 years in this region. Travertine precipitation occurs at rates of 0.1-0.3 mm/year on each side of the extensional fissures and possibly at a rate an order higher as bedded travertine on the surface. Earthquakes of magnitude M ≤ 4 occur much too frequently to have any apparent influence on travertine deposition but earthquakes with M = 4.5-5.5 occur with a frequency compatible with the travertine layering and appear to be the events recorded by the layering. Two signatures of much larger earthquakes on a 1-10 ky timescale are also recorded by travertine deposition. These are (i) incidental emplacement of massive travertine or fracturing of earlier travertine without destruction of the fissure as a venue of travertine emplacement and (ii) termination of the fissure as a site of deposition with transfer of geothermal activity to a new fracture. Palaeomagnetic estimates of fissure duration and the presence of some 25 fractures in the ˜300,000 year old Sıcak Çermik field growing at rates of 0.1-0.6 mm/year suggests that the type (ii) signature is achieved by an M ˜ 7.5 event approximately every 10,000 years.
In the Turkish sector of the Afro-Eurasian collision zone, continuing northward motion of the Arabian promontory is extruding the Anatolian region to the west. Although the East Anatolian Fault Zone (EAFZ) is recognized as the southern... more
In the Turkish sector of the Afro-Eurasian collision zone, continuing northward motion of the Arabian promontory is extruding the Anatolian region to the west. Although the East Anatolian Fault Zone (EAFZ) is recognized as the southern boundary of this tectonic escape, distributed deformation is occurring across a broad zone extending for at least 300 km to the northwest, which includes a number of major dextral and sinistral fault lineaments. The longest of these lineaments is the Ecemi~ Fault Zone, although the longterm significance of deformation, and specifically strike-slip, across this zone is disputed. This zone is also the locus of major volcanic activity in the Kayseri region. The present paper reports a palaeomagnetic study of young (1-2 Ma) lava flows which has aimed to identify recent block rotations resulting from regional deformation in this region. Rock magnetism shows the lavas to be dominated by low-Ti magnetite assemblages of primary cooling related origin. Although grain properties are predominantly multidomain, significant fractions of single domains are always present and responsible for a stable thermoremanence of normal and reversed polarity. Whilst group mean directions show that the blocks in this sector of Anatolia show the typical counterclockwise rotation resulting from tectonic escape, in this case by c. 10 ° during the last 1 Ma, larger differential rotations in both senses are identified across the Sultansazh~i Depression. Comparable differential rotations recorded by the 2.8 + 0.2 Ma incesu Ignimbrite have resulted from the pull-apart in this sector of the Ecemi~ Zone which has accommodated emplacement of the Erciyes volcanic centre since the termination of ignimbrite activity. Within the wedge-shaped terrane confined between the EAFZ in the south and the North Anatolian Fault Zone in the north, the degree of counterclockwise rotation during tectonic escape within the last 2-3 Ma has diminished from c. 25 ° in the east to c. 10 ° towards the southwest. This corresponds to a transition from highly strained to a less-strained lithosphere as the width of the semi-plastic Anatolian terranes confined between the Arabian-Eurasian pincer broadens out to the west.
Following final closure of the Neotethyan Ocean during the late Miocene, deformation in central Turkey has led to crustal thickening and uplift to produce the Anatolian Plateau followed by westward extrusion of terranes by strike -slip.... more
Following final closure of the Neotethyan Ocean during the late Miocene, deformation in central Turkey has led to crustal thickening and uplift to produce the Anatolian Plateau followed by westward extrusion of terranes by strike -slip. Widespread volcanism has accompanied this latter (neotectonic) phase, and palaeomagnetic study of the volcanism shows a coherent record of differential block rotations, indicating that the Anatolian region is not a plate (or 'platelet') sensu stricto but is undergoing distributed internal deformation. To evaluate the scale of neotectonic rotations in the transition zone near the western limit of tectonic escape and the border of the extensional domain in central-west Turkey, we have studied the palaeomagnetism at 82 sites in volcanic suites distributed along a f140-km lineament with north -south trend and ranging in age from 18 to 8 Ma. Comparable deflection of magnetic remanence from the present field direction is identified along the full length of the lineament. A mean clockwise rotation of 12.3 F 4.2j is determined for this western sector of the Anatolian strike -slip province. Since similar rotations are observed in the youngest and oldest units, this cumulative rotation occurred after the late Miocene. When interpreted together with results elsewhere in Anatolia, it is inferred that the rotation is later than crustal thickening and uplift of the Anatolian Plateau and entirely a facet of the tectonic escape. Inclinations are mostly f10j shallower than the predicted Miocene field and are considered to reflect the presence of a persistent inclination anomaly in the Mediterranean region. Larger rotations departing from the regional trend are also observed within the study region, but are confined to the vicinity of major faults, notably those bounding the Afyon-Aks ßehir Graben.
- by Halil Gursoy and +1
- •
- Geology, Geochemistry, Geophysics, Palaeomagnetism
Magmatism forming the Central Anatolian Volcanic Province of Cappadocia, central Turkey, records the last phase of Neotethyan subduction after ∼11 Ma. Thirteen large calc-alkaline ignimbrite sheets form marker bands within the... more
Magmatism forming the Central Anatolian Volcanic Province of Cappadocia, central Turkey, records the last phase of Neotethyan subduction after ∼11 Ma. Thirteen large calc-alkaline ignimbrite sheets form marker bands within the volcano-sedimentary succession (the Ürgüp Formation) and provide a robust chronostratigraphy for paleoecologic evaluation of the interleaved paleosols. This paper evaluates the chronologic record in the context of the radiometric, magnetostratigraphic and lithostratigraphic controls. Previous inconsistencies relating primarily to K/Ar evidence were reason for the initiation of an integrated study which includes 40 Ar/ 39 Ar dating, palaeomagnetic and stratigraphic evidence. The newly determined 40 Ar/ 39 Ar-ages are in agreement with Ar/Ar and U/Pb data meanwhile published by Pauquette and Le Pennec (2012) and . The 40 Ar/ 39 Ar-ages restrict the end of the Ürgüp Formation to the late Miocene. The paleosol sequence enclosed by the ignimbrites is thus restricted to the late Miocene, the most intense formation of pedogene calcretes correlating with the Messinian Salinity Crisis.
- by Halil Gursoy and +1
- •
- Geochemistry, Neogene
Magnetic properties and heavy metals in atmospheric particulate matter were compared in different regions. The atmospheric particulate is contaminated by local anthropogenic activity. Magnetic parameters can be used as a practical tool... more
Magnetic properties and heavy metals in atmospheric particulate matter were compared in different regions. The atmospheric particulate is contaminated by local anthropogenic activity. Magnetic parameters can be used as a practical tool for mapping degrees of heavy metal pollution. a b s t r a c t Magnetic phases are a common component of dustfall samples and mineral magnetic studies have been increasingly exploited for air quality studies in recent years to assess the source and spatial-temporal distribution of anthropogenic magnetic particulates and associated heavy metals. Here we report a comparative study of magnetic and chemical properties of atmospheric particulate deposits from rural areas of Inner Mongolia and urban regions of Hebei and Beijing. The sample sets were collected at 13 monitoring stations by the gravimetric method between April 2009 and March 2010. At the rural sites paramagnetic clays, complemented by hematite and goethite recognized by Isothermal Remanent Magnetism (IRM) and Diffuse Reflectance Spectra (DRS) investigations, accompany fine grained magnetite as an important fraction. Although present as a residual phase in samples from the urban regions, coarsegrained magnetite of anthropogenic origin dominants the magnetic signatures in these latter environments. Systematic variations with local anthropogenic activity including traffic, the mining of ores and a range of industrial emissions are identified, together with a seasonal signature in the Beijing area. We use correlations between magnetic concentration-related parameters, notably magnetic susceptibility, and the Pollution Load Index to demonstrate how magnetic parameters can be used as a practical tool for mapping degrees of heavy metal pollution and tracing the sources of pollutants in dustfall samples.