Ian D. Somerville

• PhD
• Professor (Associate) at University College Dublin

The southern margin of the Junggar Basin (SMJB) represents the typical intra‐continental basin–orogen coupling structure of the Central Asian Orogenic Belt and is a key area to study the deformation mechanisms and the geodynamic evolution processes of the North Tianshan Orogen. Herein, we compiled data from boreholes, gravity and magnetism, seismic...

Plain Language Summary Nearly synchronous global changes in geomagnetic polarity give both a detailed irregular pacing to geological time and provide a glimpse into heat transfer processes across the core—mantle boundary which drives the Earth's geodynamo. Although the Late Carboniferous is characterized by some well‐studied reversals, details of t...

The late Asbian appears to mark the initial, well‐documented, onset of far‐field glacio‐eustatic changes in equatorial Mississippian strata. This work unravels the nature of cyclicity in upper Asbian shallow marine carbonates, using a combination of petrographic study, rock magnetic proxies and astrochronological testing on samples from the Trowbar...

First occurrences of selected foraminifers and their interpreted phylogenies in the uppermost Arundian Substage of the South Cumbria Shelf, northern England, allows the distinction of four biostratigraphic events. Event A1 is characterised by the occurrence of occluded Nodosarchaediscus, Consobrinellopsis, and Archaediscus krestovnikovi and is assi...

First occurrences of selected foraminifers and their interpreted phylogenies in the uppermost Arundian Substage of the South Cumbria Shelf, northern England, allows the distinction of four biostratigraphic events. Event A1 is characterised by the occurrence of occluded Nodosarchaediscus, Consobrinellopsis, and Archaediscus krestovnikovi and is assi...

A study of calcareous algae from the late Viséan to Serpukhovian interval in basins from the western margin of Palaeotethys (basins located currently in Western Europe and Northern Africa) shows varied responses in terms of palaeoecological diversity, specimen abundance, genus richness and taxonomic distinctness for the low-latitude basins. Alg...

Foraminiferal diversity and taxa richness from beds transitional between the Asbian and Brigantian substages (Middle Mississippian) show patterns of secular change which allow detailed inter-regional correlations to be established. Foraminifera from the Askrigg Block, Stainmore Trough, Alston Block, South Cumbria Shelf and Solway Basin show similar...

Revision of foraminifers, algae and problematic algae of well-known late Viséan formations in the Jerada syncline in the Eastern Meseta, Azrou-Khenifra Basin in the Central Meseta and Oued Cherrat in the Western Meseta, suggests that the recognition of the chronostratigraphic units within this period lacks most of the foraminiferal markers in the W...

Five types of reefs are described from the northern and southern parts of the Azrou-Khenifra Basin generated by the interactions of microbes and coral communities. The type 1 microbial reefs grew in both shallow- and deep-water settings, with a strong control by glacioeustasy. Type 2 microbial reefs developed in more tranquil periods, associated wi...

The degree to which emergent surfaces are correlated in late Asbian carbonate successions in Britain and Ireland is assessed by the integration of detailed biostratigraphy and diversity trends in foraminifers. Data are related to the Trowbarrow Quarry section in northern England, which provides a reference section for the upper Asbian because of it...

Despite the importance of south Cumbrian sections for the Arundian–Holkerian (mid Viséan) boundary, beyond the stratotype proposed at Barker Scar in 1976, little else is known regionally about this boundary and its relationship to adjacent formations. We re-evaluate the Dalton Formation, making its upper and lower boundaries regionally more consist...

A detailed biostratigraphy is established, using the high foraminiferal abundance and diversity at Trowbarrow Quarry, which is also proposed as a stratotype section for the late Asbian (late Visean), a substage not previously formally subdivided. The foraminiferal assemblages suggest that the early Asbian has to be revised, which has implications f...

The succession in the Tizra Formation shows an excellent exposure of a small open marine platform where alternating microbial boundstones (buildups) and oolitic/bioclastic grainstone (shoals) and packstone facies tempestites occur repetitively for a sort interval only 0.55 Myr, an scenario unknown in the geological record. The relatively small exte...

The Carboniferous outcrops from Adarouch (central Morocco) are composed of siliciclastic and carbonate rocks, and the latter have yielded abundant fossils. The upper part of the marine succession in the Idmarrach Formation and its laterally equivalent Tirhela Formation belong to the Bashkirian. More recent investigations of poorly preserved coral a...

Foraminiferal revision of the Holkerian Stratotype of Britain at Barker Scar, Holker Hall, south Cumbria, UK, allows the subdivision of the section into the Cf4δ, Cf5α and Cf5β subzones (the latter being further subdivided into a lower Cf5β1 and upper Cf5β2 intervals). The base of Cf5α subzone at the base of bed C and base of Cf5β subzone from the...

The correlation of disparate mid- to late Viséan platform carbonate successions of the Great Scar Limestone Group across northern England formerly relied heavily upon a coral and brachiopod biozonation scheme erected in the early 20 th century. This subsequently guided the development of a regional chronostratigraphic scheme some sixty years later...

In this study, middle to late Mississippian microfossil assemblages from the Maritimes Basin of eastern Canada (Nova Scotia, SW Newfoundland, and New Brunswick) are closely compared to those from Western Paleotethys basins. The comparison is focused mainly on foraminifers and calcareous algae. Most foraminifers and algae described from the Maritime...

The sedimentary basin is a basic geological unit in the Earth system: its formation and evolution are controlled mainly by plate tectonics and geodynamics, which have produced a variety of basin types. The development and evolution of various basins depend not only on the tectonic effect of lithospheric plate but also on sublithospheric, and Earth...

In this study of Mississippian rocks in Ireland, it is now recognized, based on faunal evidence, that several upper Viséan limestone formations which were previously excluded from the Serpukhovian now belong, in part, to the lower two substages of the Serpukhovian. A reassessment of previous foraminiferal determinations, together with new foraminif...

East China experienced alternating tectonic extension and compression with ambiguous tectonic settings in the Mesozoic-Cenozoic interval. Long-term extensional episodes associated with the subduction retreat of the Paleo-Pacific and Pacific slabs have been widely studied. The compressional events, of which basin inversion is a typical case, are les...

Foraminifera have been used to revise the biostratigraphy of all known Mississippian outcrops in Morocco cited either as early Viséan (or its equivalent V2a or V2a/b chronozones or the regional Cfm1 biozones), or mid Viséan (or the foraminiferal zones V2b-V3a or Cfm2-Cfm3 biozones). This group of microfossils occur in shallow-water limestones withi...

A new early Visean coral assemblage has been recorded from turbidite facies in the southern part of the Azrou-Khenifra Basin, northwest of Khenifra, central Morocco. The newly discovered Ba Moussa West (BMW) coral fauna includes Siphonophyllia khenifrense sp. nov., Sychnoelasma urbanowitschi, Cravenia lamellata, Cravenia tela, Cravenia rhytoides, T...

Lower Carboniferous rocks are well exposed in the northwestern part of the Moscow Basin. The Serpukhovian Stage is widely represented in that region and it is composed of three lithostratigraphic units: Rovnoe Formation (Tarusian Regional Stage), Poneretka Formation (Steshevian Regional Stage) and Uglovka Formation (Protvian Regional Stage). Coral...

The tectonic evolution history of the South China Sea (SCS) is important for understanding the interaction between the Pacific Tectonic Domain and the Tethyan Tectonic Domain, as well as the regional tectonics and geodynamics during the multi-plate convergence in the Cenozoic. Several Cenozoic basins formed in the northern margin of the SCS, which...

A new foraminiferal subzone (Cf5α or MFZ12α) in between the classical foraminiferal zonal biozones is characterized by the first occurrence of Archaediscus at concavus stage, primitive species of Pojarkovella , as well as the first Endothyranopsis s.s. This interval is represented in England, France and Morocco (in the western Palaeotethys) and in...

Earthquake geohazards that occur throughout the Borneo Block, especially in SW Borneo, cannot be reconciled within the classical earthquake mechanism and a uniform stress field, and unfulfilled earthquake forecast for many years. In this paper, we present a new inventory of 37 Borneo earthquakes, and focal mechanisms show that in NE Borneo earthqua...

Late Mississippian carbonates in southern Montagne Noire are dominantly domical to laterally‐accreted microbial mounds in some formations, as well as stratiform microbial limestones occurring in hundreds of olistoliths within a flysch basin, constituting pieces of a giant puzzle that are used to help reconstruct a platform in a region that is no lo...

A detailed revision of foraminiferal zonal schemes in sections throughout Europe and North Africa for the Viséan–Serpukhovian boundary interval suggests that several foraminiferal taxa might have the potential to form reliable markers throughout the Palaeotethys. This would support the currently investigated boundary definition based on the First A...

Base-metal-sulfide deposits were mined historically on the Isle of Man, principally from quartz-vein deposits in Ordovician-Silurian age metasedimentary rocks. During a study of dolomitization of overlying Carboniferous sedimentary rocks, an extensive (140 m long, 1-10 m wide) sphalerite-bearing breccia deposit (~7 wt.% Zn) was found. Mineralizatio...

On September 28, 2018, a Mw7.5 earthquake occurred near Sulawesi, Indonesia as a result of strike-slip faulting at shallow depth within the interior of the Molucca Sea Microplate that forms a part of the broader Sunda Plate. Focal mechanism solutions and distribution for the earthquakes indicate rupture occurred on a left-lateral NNW-SSE- to N-S-st...

Submarine canyons are common features on the northern South China Sea (SCS) continental slope. Three main submarine canyon systems were observed by multi-beam investigation and evaluated by a pre-existing sedimentary dataset. They include the Xisha Canyon Zone, Shenhu Canyon Zone, and Taiwan Canyon Zone on the northern SCS continental slope which d...

The upper Viséan-lower Serpukhovian Roque Redonde Formation in the southern part of the Montagne Noire, SW France, contains carbonate mounds with predominant micropeloidal facies tens of meters thick representing paleotopographic highs. Calcareous green algae, including representatives of the Dasycladales and Bryopsidales, are relatively common wit...

The late Viséan to early Bashkirian shallow-water carbonate Valdediezma Platform in the Picos de Europa Province of the Cantabrian Zone, has been subdivided into eight microbiotic intervals by means of similarity clusters (using the Morisita coefficient). The most complete Viséan-Bashkirian interval is represented in the Valdediezma Valley – Jitu l...

Coastal outcrop in north County Dublin exposes platform to slope carbonates on the NE margin of the Dublin Basin, the centre and south of which hosts much of the world-class Irish Midlands Pb-Zn ore deposits. The studied limestones contain a variety of fault-related dolomite bodies and vein mineralisations (including calcite, quartz and Cu minerals...

The eastern part of the North China Craton has experienced cratonic destruction during the Mesozoic–Cenozoic period. However, the mechanism and geodynamic process of cratonic destruction is still not clear. The Shandong Province is a typical region that suffered the Yanshanian (Jurassic to Cretaceous) tectono-thermal event relating to the cratonic...

The Qinling-Dabie-Sulu Orogen was formed by the collision of the North and South China blocks during the Indosinian Period. The intracontinental deformation was subsequently developed during the Late Triassic to Early Jurassic in the northeastern, eastern, and southeastern parts of eastern North China Block with different structural patterns. In th...

The Qilian Block is one of many continental blocks involved in the early Paleozoic orogenesis of the Central China Orogen, which experienced complex interaction with adjacent blocks and orogens. In this study, we present zircon U–Pb–Hf isotopic, whole-rock elemental, and Sr–Nd isotopic data of the early-middle Silurian intrusive rocks in the Lanzho...

The Tarim Basin, situated between the Paleo-Asian tectonic domain and the Proto-Tethys tectonic domain, has undergone a complex tectonic evolutionary process under various geodynamic conditions and has provided abundant information about the dynamic evolution of the peripheral orogens. From the Sinian to Early Ordovician, the Tarim–Qaidam Block was...

This paper presents new results on zircon U–Pb dating of a two-mica schist from the Qinling Group in the core of the North Qinling Orogenic Belt (NQB), Central China, with the aim of constraining the formation time of the Qinling Group, and the tectonic affinity of the North Qinling Microcontinent. Zircon U–Pb dating indicates that the protolith of...

The ductile shear zones in the North Qinling Orogen, such as the Luonan-Luanchuan, Guanpo-Qiaoduan, Zhuyangguan-Xiaguan, and Shangdan shear zones, play an important role in the preclosure and postclosure evolution of the Proto-Tethys Ocean. On the basis of detailed macrostructural/microstructural analysis and quartz C-axis electron backscattered di...

Early Cretaceous tectono-magmatic activity in the eastern North China Craton has long been linked to cratonic destruction, but no systematic investigations about the geodynamic processes have been performed. Early Cretaceous diabases, lamprophyres, andesites and dacites are distributed in the western Shandong Peninsula, and these rocks have a close...

Post-orogenic extension is the last stage of a tectonic process towards the end of each Wilson cycle in both ancient and modern continental collisional zones, but their dynamics, controlling factors, and roles for the post-orogenic extension processes remain debatable. We present the first two-dimensional thermo-mechanical numerical model of double...

The new species Lithostrotion termieri Rodríguez & Somerville is described. It shows very large corallites of the rugose genus Lithostrotion Fleming. It has been recorded up to now only in upper Viséan rocks from the type locality, the Akrab ridge, Morocco also called Tizi Ben Zizouit by Termier & Termier (1950), who identifi ed it as Lonsdaleia fl...

As a complex paleo-ocean located between the Tarim-North China and the Sibamusu/Baoshan blocks, the Proto-Tethys Ocean was opened from the rifting of the Supercontinent Rodinia and mainly closed at the end of the Early Paleozoic. The known studies suggest that there were many continents and/or micro-continents in the Proto-Tethys Ocean. During clos...

The Dupal anomaly has been a frequently discussed feature since it was first proposed three decades ago. We here limit the distribution of the Dupal anomaly based on more than 10 000 Sr–Nd–Pb isotopic composition analyses and classify the anomaly into three types, located in three different oceans and with different mechanisms of formation. The Dup...

The Tinjar-West Baram Line is a NW-trending trans-lithospheric fault in northern Kalimantan; its northwestern extension into the South China Sea (SCS) is the West Baram Line. In this paper, we propose that the geodynamic processes of the proto-South China Sea (PSCS) played a key role in the formation and evolution of the Tinjar-West Baram Line, bas...

The East China Sea Shelf Basin (ECSSB), the Pearl River Mouth Basin (PRMB) and the Taixinan Basin (TXNB) in the northern continental margin of the South China Sea (SCS) are important oil- and gas-bearing basins on the Western Pacific Continental Margin. During the Paleocene to Late Miocene, their strata can be compared, and the lithofacies were con...

We calculate a predicted interpolating result of surface heat flow based on a data set with 2674 measurements in the Western Pacific. Comparisons of heat flow profiles between the back-arc basin and the corresponding subduction slab show that the cold subducting slab may cause indirectly the thermal activities of back-arc basins. We estimate that v...

Transform faults in back-arc basins are the key to revealing the evolution of marginal seas. Four marginal basins in the Western Pacific, i.e. the South China Sea (SCS), Okinawa Trough (OT), West Philippine Basin (WPB) and Shikoku-Parece Vela Basin (SPVB), were studied to redefine the strikes and spatial distribution of transform faults or fracture...

Earth system includes Earth’s surface system and deep Earth system. This Special Issue tries to establish a link between these two systems. It contains 46 contributions on Earth system evolution of the Pacific and Indian oceans and the South China Sea. The themes cover the relationship of ocean to continent, tectonic jumping, morphotectonics in the...

The Serpukhovian coral assemblages from Idmarrach and Tirhela formations (Adarouch, Morocco) have been studied. They yielded quite diverse assemblages with a total of 32 rugose and 1 tabulate species. The distribution of corals in the sections Idmarrach 1, 2, 3, and 4 and Tirhela 1 and 2 has been established, which include Serpukhovian and Bashkiri...

The Carboniferous outcrops from the Azrou-Khenifra Basin (central Morocco) have yielded solitary and fasciculate aulate corals. Although mostly rare, their presence has significance for extending the known stratigraphic range of two genera. Both Solenodendron and Semenoffia which were previously restricted to the Tournaisian-Viséan interval are now...

As an active margin of the Pacific Plate, the ocean-continent transition zone records major tectonic events from the Late Mesozoic to the present-day. The development of the transition zone between the Western Pacific Ocean and the East Asian Continental Margin occurred in two stages. In the first stage, the formation of the Songliao and Bohai Bay...

By using magnetic anomaly identifications, onshore and offshore exploratory wells, ODP drillings, isotopic dating and orthochronology results, this paper summarizes the tectonic event sequence (including extension, back-arc spreading, subsidence, convergence/compressive deformation and thrusting) of the marginal basins of the NW Pacific and extract...

The Borneo Accretionary Orogen (BAO) is located in a central position of SE Asia, surrounded by the long-lived westward subduction of the Pacific Plate, northward subduction of the Indian Plate beneath the Eurasian Plate and a passive continental margin of the South China Sea. Based on the previous studies in stratigraphy, structural geology and ge...

This paper presents the results of U-Pb dating of detrital zircons from six metasedimentary rocks in the Taowan and Kuanping groups in the northern margin of the North Qinling Orogenic Belt (NQB), central China, for constraining the tectonic affinity of the NQB, the existence time and tectonic features of the Kuanping Ocean and the accurate norther...

A continuous succession of the upper part of the Alba Formation is recorded in the Vegas de Sotres section in the Cantabrian Mountains, northern Spain. This section contains slightly shallower-water facies than elsewhere and as a result is particularly rich in foraminifers. Characterization of the late Visean to Serpukhovian interval in coeval deep...

The ocean floor is leaky because it has numerous faults, cracks and joints upon formation and during the process of seafloor spreading. In time, these fractures are often closed after ocean floor cooling, hydrothermal circulation, and vein filling. The crack-seal mechanism of fractures of the oceanic crust is thus important for understanding its ki...

A rationalized lithostratigraphy for the Great Scar Limestone Group of the southeast Askrigg Block is established. The basal Chapel House Limestone Formation, assessed from boreholes, comprises shallow-marine to supratidal carbonates that thin rapidly northwards across the Craven Fault System, onlapping a palaeotopographical high of Lower Palaeozoi...

There is a continuing hot debate on whether the geodynamics in the West Pacific indicate either a marginal basin or back-arc basin, since the nature, evolution and formation mechanism are not well known. Research on the Okinawa Trough (OT), which is an active back-arc basin, has important scientific significance for discussing the opening and devel...

The coral content of the Visean rocks from the Guadiato Area (SW Spain) have been studied during the last 25 years. Part of the coral assemblages have been previously described, but never as whole. The 69 recorded coral species belonging to Rugosa, Tabulata and Heterocorallia are illustrated. The family Antiphyllidae is represented by two genera an...

Following the collecting and analyzing of field data on the geometry and kinematics characteristics of ground fissures in the northern North China Plain (NNCP), this paper shows that en échelon ground fissures or tectonic ground fissures with a length of several meters to tens of kilometers extending along active faults are possibly controlled by u...

The Zhuanghai area is located in the northern part of the Jiyang Depression, Bohai Bay Basin, which is a superimposed basin. In this basin, there are very thick Cenozoic sediments that unconformably overlie Lower Palaeozoic rocks, which form buried hills (topographic highs). Through core description and microscopic observations, the diagenetic char...

The North Qinling Terrane, including the Kuanping, Erlangping and Qinling groups, is located in the northern part of the Qinling Orogen. Here we present results from structural analyses of the North Qinling Terrane and its surrounding regions. Three episodes of deformation (D1, D2 and D3) are recognized. The D1 deformation is characterized by NNE-d...

Revision of several important Carboniferous stratigraphic successions in basins in the Saharan Platform allows us to propose distinct biostratigraphical boundaries for the upper Viséan, lower and upper Serpukhovian and lower Bashkirian, with the latter boundary separating upper Mississippian from lower Pennsylvanian strata. The boundaries are not o...

Lithofacies and faunal assemblage affinities of the Helan Mountains and its adjacent blocks are explored using field investigations and analysis of previous results. The tectonic affinity between the Alxa Block and the North China Block is analyzed by means of LA-ICP-MS detrital U–Pb zircon age spectrums. The Early Paleozoic stratigraphic framework...

The tectonic evolution and sedimentary characteristics of the Carboniferous-Permian rocks of the Turpan-Hami Basin have been analysed. Initially, a joint inversion of gravity, magnetic, seismic data and the established model of electrical profiles was synthesized to create a new geological interpretation. Discussion on the tectonic characteristics...

A detailed study of foraminiferal assemblages recorded in limestones from northern England in the Stainmore Trough and Alston Block permits their assignment to different European substages than in previous studies. Comparisons with foraminiferal assemblages, mostly from Russia, allow the biozonations to be correlated with the Viséan, Serpukhovian a...

During the Mesozoic and Cenozoic, the Qinling Mountains formed a nearly E–W-striking uplifted mountain range separating the North China and South China blocks, while the Taihang Mountains formed a S–N-striking uplifted mountain range within the central North China Block. Thus, the strikes of both are perpendicular to each other. In order to investi...

Seismic and drilling well data were used to examine the occurrence of multiple stratigraphic unconformities in the Tarim Basin, NW China. The Early Cambrian, the Late Ordovician and the late Middle Devonian unconformities constitute three important tectonic sequence boundaries within the Palaeozoic succession. In the Tazhong, Tabei, Tadong uplifts...

A revised Mississippian lithostratigraphy of County Galway (western Ireland) with an analysis of carbonate lithofacies, biostratigraphy, depositional environments and palaeogeographic reconstructions utilising new borehole data Abstract An integrated study of borehole data and outcrop of Mississippian (late Tour-naisian to late Viséan) rocks in Co....

Resumen Se ha abordado una revision de los corales solitarios de la subfamilia Axophyllinae y la descripción de los axo-phyllinos recolectados en el Carbonífero de Sierra Morena (Suroeste de España). Este grupo de corales ha sido men-cionado frecuentemente en el Cabonífero desde Australia hasta América del Norte y desde China hasta Europa Occidenta...

Recibido: 15-diciembre-2015. Aceptado: 15-marzo-2016.Publicado en formato electrónico: 30-marzo-2016. Palabras clave: Sistemática, Rugosa, Tabulata, Carbonífero, Misisípico Marruecos.

Foraminiferal studies on late Mississippian (Serpukhovian) limestones from northern England allow a well-constrained correlation between the western European regional substages for the early Namurian (Pendleian, Arnsbergian and Chokierian) with the Russian regional substages for the international Serpukho vian (Tarusian, Steshevian, Protvian and Za...

The Qinling Orogen in central China preserves the records of a complex geological and tectonic history, and also carries abundant mineral resources. Previous investigations on the Qinling Orogen have identified that the final transition from Palaeo-Tethys Ocean to a continental orogen occurred in the Triassic, although the timing of the oceanic clo...

Viséan limestones on the Isle of Man host numerous examples of fault-controlled and fracture-controlled dolomitization, which have been investigated to determine their macro-scale to micro-scale characteristics, geofluid origin, timing and relation to basin evolution. Geobodies composed of fabric destructive, ferroan, nonplanar dolomite range from...

Spatial and temporal variations of Carboniferous sediment accumulation within the northwestern part of the northern flank of the Tindouf Syncline in Saharan Morocco allowed to distinguish 16 lithofacies types. The predominant sedimentation pattern is cyclic, with the overall succession recording a major regressive trend. Outer platform siliciclasti...