scholarly journals Controls of Depositional Environments on Reservoir Quality in Terms of Porosity and Permeability Gabo Field Niger Delta

2019 ◽  
Author(s):  
Richmond Ideozu ◽  
Tochukwu Nduaguibe
Keyword(s):  
Niger Delta ◽  
High Energy ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Reservoir Quality ◽  
Fine Grained ◽  
Sedimentary Structures ◽  
Facies Associations ◽  
Porosity And Permeability ◽  
Distributary Channel

The controls of depositional environments on reservoir quality have been evaluated in terms of porosity and permeability of the Gabo Field, Niger Delta, Nigeria. Data used in this research include Well logs, Core data and photos, and grain size analysis for Wells 51 and 52 in the study area. Standard methods as applicable in petrophysical and sedimentological analysis has been adopted. Thirteen reservoir units have been identified in wells 51 and 52 which had 5 reservoirs cored each. The lithofacies units of the identified reservoirs across the study area, comprise pebbly sands, coarse -, medium -, fine- and very fine-grained sands, sandy mud, silty sands and heteroliths. The heteroliths – very fine-grained silty muds are highly bioturbated. Ophiomorpha and skolithos are the major trace fossils with sedimentary structures (ripple lamination, wavy lenticular and planar beds, cross bedded sands, coarsening and fining upward). The facies associations interpreted for the study area are Channel and Coastal barrier systems and the environment of deposition as distributary channel, upper and lower shoreface. The sedimentary processes that deposited facies ranged from high energy regimes, reworking by waves to low energy with periodic influx of silts and muds. The average porosity and permeability for reservoirs in Well 51 is 16.7% and 1317 Md, reservoirs in Well 52 is 28.2% and 2330Md whereas porosity range for the study area is 2% - 32% and permeability is 1.2 – 10600 Md. The reservoir quality reservoir of the sand units in Well 51 (7, 9 and 13) and Well 52 (5, 7, 9, 11 and 13) is excellent - good, this is because of the dynamics environments of deposition (upper shoreface and distributary channel) as well as the mechanisms that play out during deposition such as bioturbation, sorting, sedimentary structures formed. Whereas the poor quality across the reservoirs especially the lower shoreface and prodelta facies is as result of lack bioturbation, connectivity, multiplicity of burrows that may have been plugged by clay and intercalation of shale and sand (heteroliths). This research has shown that environments of deposition have direct influence the reservoir quality in terms of porosity and permeability.

scholarly journals Reservoir quality and its controlling diagenetic factors in the Bentiu Formation, Northeastern Muglad Basin, Sudan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousif M. Makeen ◽  
Xuanlong Shan ◽  
Mutari Lawal ◽  
Habeeb A. Ayinla ◽  
Siyuan Su ◽  
...  
Keyword(s):  
Clay Content ◽  
Petroleum Exploration ◽  
Reservoir Quality ◽  
Burial Depth ◽  
Petroleum Reservoir ◽  
Fine Grained ◽  
Porosity And Permeability ◽  
Negative Role ◽  
Crevasse Splay ◽  
Channel Deposits

AbstractThe Abu Gabra and Bentiu formations are widely distributed within the interior Muglad Basin. Recently, much attention has been paid to study, evaluate and characterize the Abu Gabra Formation as a proven reservoir in Muglad Basin. However, few studies have been documented on the Bentiu Formation which is the main oil/gas reservoir within the basin. Therefore, 33 core samples of the Great Moga and Keyi oilfields (NE Muglad Basin) were selected to characterize the Bentiu Formation reservoir using sedimentological and petrophysical analyses. The aim of the study is to de-risk exploration activities and improve success rate. Compositional and textural analyses revealed two main facies groups: coarse to-medium grained sandstone (braided channel deposits) and fine grained sandstone (floodplain and crevasse splay channel deposits). The coarse to-medium grained sandstone has porosity and permeability values within the range of 19.6% to 32.0% and 1825.6 mD to 8358.0 mD respectively. On the other hand, the fine grained clay-rich facies displays poor reservoir quality as indicated by porosity and permeability ranging from 1.0 to 6.0% and 2.5 to 10.0 mD respectively. A number of varied processes were identified controlling the reservoir quality of the studies samples. Porosity and permeability were enhanced by the dissolution of feldspars and micas, while presence of detrital clays, kaolinite precipitation, iron oxides precipitation, siderite, quartz overgrowths and pyrite cement played negative role on the reservoir quality. Intensity of the observed quartz overgrowth increases with burial depth. At great depths, a variability in grain contact types are recorded suggesting conditions of moderate to-high compactions. Furthermore, scanning electron microscopy revealed presence of micropores which have the tendency of affecting the fluid flow properties in the Bentiu Formation sandstone. These evidences indicate that the Bentiu Formation petroleum reservoir quality is primarily inhibited by grain size, total clay content, compaction and cementation. Thus, special attention should be paid to these inhibiting factors to reduce risk in petroleum exploration within the area.

scholarly journals Facies Evaluation and Depositional Environments of Carbonates of the Bagh Group, Dhar District, Madhya Pradesh, India

2021 ◽  
Vol 38 (1) ◽  
pp. 33-40
Author(s):  
Sreejita Chatterjee ◽  
Dhiren Kumar Ruidas
Keyword(s):  
Grain Size ◽  
Large Scale ◽  
Energy Condition ◽  
Size Variation ◽  
High Energy ◽  
Depositional Environments ◽  
Small Scale ◽  
Peninsular India ◽  
Sedimentary Structures ◽  
Nodular Limestone

A significant event of marine transgression took place in Central India during Late Turonian-Coniacian. Fossiliferous marine succession of Bagh Group is one of the few carbonate successions exposed in peninsular India which was in focus of the current study for understanding this event. The signatures of this event were identified in the carbonate succession. The carbonates of Bagh Group are composed of two formations: the lower part is represented by Nodular limestone Formation which is overlain by Bryozoan limestone Formation at the top. On the basis of grain size variation and sedimentary structures, the Nodular limestone is divisible into three facies: facies ‘A’, facies ‘B’ and facies ‘C’. A hardground exists between facies B and facies C. Lack of sedimentary structures and high mud content indicates low energy depositional setting for the Nodular limestone Formation. Similarly, Bryozoan limestone Formation is divisible into five facies: facies ‘D’, facies ‘E’, facies ‘F’, facies ‘G’ and facies ‘H’ based on grain size variation and sedimentary structures. All of these five facies are fossiliferous. Glauconites are present within facies ‘G’ and have two modes of occurrence - as infilling within Bryozoan limestone and as altered feldspar. Presence of both small- and large-scale cross-stratification in Bryozoan limestone with lesser mud content are indicative of high energy shallow marine conditions. Large-scale cross-stratifications are possibly representing tidal bars while the small scale cross stratifications are formed in inter bar setting. Presence of reactivation surfaces within facies ‘E’ also supports their tidal origin. Increase in depositional energy condition is also evident from dominated by packstone facies.

APPROACHES TO PALAEOGEOGRAPHIC RECONSTRUCTIONS OF THE LATROBE GROUP, GIPPSLAND BASIN, SOUTHEASTERN AUSTRALIA

2005 ◽  
Vol 45 (1) ◽  
pp. 581 ◽  
Author(s):  
T. Bernecker ◽  
A.D. Partridge
Keyword(s):  
Co2 Storage ◽  
Depositional Environments ◽  
Petroleum Systems ◽  
Fine Grained ◽  
Southeastern Australia ◽  
Depositional System ◽  
Facies Associations ◽  
Marine Fossils ◽  
Coal Accumulation ◽  
Gippsland Basin

In the Gippsland Basin, the seaward extent of paralic coal occurrences can be mapped in successive time slices through the Paleocene and Eocene to provide a series of straight to gently arcuate surrogate palaeoshorelines within the petroliferous Latrobe Group. Palaeogeographic reconstructions that incorporate this information provide a unique perspective on the changes affecting a siliciclastic depositional system on a passive continental margin where basin development has been primarily controlled by thermal sag. In contrast, the absence of calcareous marine fossils and lack of extensive, widespread and thick fine-grained sediments on the marine shelf and continental slope, beyond the seaward limits of coal accumulation, have contributed to the false impression that the Latrobe Group accumulated in a largely non-marine basin. Based on the proposed model for palaeoshoreline delineation, seismic data, sequence analysis, petrography and palynology can be integrated to subdivide the main depositional environments into distinct facies associations that can be used to predict the distribution of petroleum systems elements in the basin. The application of such palaeogeographic models to the older section of the Latrobe Group can improve the identification of these petroleum systems elements in as yet unexplored parts of the Gippsland Basin. Given the recent attention paid to the basin as a CO2 storage province, palaeogeographic interpretations may be able to assist with the selection of appropriate injection sites.

scholarly journals Grain size statistics and depositional pattern of the Ecca Group sandstones, Karoo Supergroup in the Eastern Cape Province, South Africa

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Christopher Baiyegunhi ◽  
Kuiwu Liu ◽  
Oswald Gwavava
Keyword(s):  
South Africa ◽  
Grain Size ◽  
Depositional Environments ◽  
Energy Conditions ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Equal Proportion ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Fine Grained

AbstractGrain size analysis is a vital sedimentological tool used to unravel the hydrodynamic conditions, mode of transportation and deposition of detrital sediments. In this study, detailed grain-size analysis was carried out on thirty-five sandstone samples from the Ecca Group in the Eastern Cape Province of South Africa. Grain-size statistical parameters, bivariate analysis, linear discriminate functions, Passega diagrams and log-probability curves were used to reveal the depositional processes, sedimentation mechanisms, hydrodynamic energy conditions and to discriminate different depositional environments. The grain-size parameters show that most of the sandstones are very fine to fine grained, moderately well sorted, mostly near-symmetrical and mesokurtic in nature. The abundance of very fine to fine grained sandstones indicate the dominance of low energy environment. The bivariate plots show that the samples are mostly grouped, except for the Prince Albert samples that show scattered trend, which is due to the either mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under shallow marine environments for samples from the Prince Albert, Collingham and Ripon Formations, while those samples from the Fort Brown Formation are lacustrine or deltaic deposits. The C-M plots indicated that the sediments were deposited mainly by suspension and saltation, and graded suspension. Visher diagrams show that saltation is the major process of transportation, followed by suspension.

scholarly journals Stratigraphic Investigations into the Late Miocene-Early Pliocene of the Northern Aorangi Range, Wairarapa

2021 ◽  
Author(s):  
◽  
Tamsin Lesley Beatrice Bertaud-Gandar
Keyword(s):  
Cross Sections ◽  
Late Miocene ◽  
High Energy ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Geological History ◽  
Early Pliocene ◽  
Lithostratigraphic Units ◽  
Uplift And Erosion

<p>The late Miocene-early Pliocene geology of the Makara and Ruakokoputuna Valleys in the northern Aorangi Range, south-east Wairarapa, is described in detail. In this area, a succession of Neogene sedimentary units laps onto basement rocks of Cretaceous age, and late Miocene-early Pliocene stratigraphy varies markedly, from bathyal mudstone to high energy coastal environments, over distances of only a few kilometres. Sections were measured at four key locations, which provided reference sites for stratigraphic changes across the study area. Additional detailed field mapping was carried out around Te Ahitaitai Ridge. Depositional environments were interpreted using grain size analysis, macrofossil and foraminiferal assemblages, and palynology. Foraminiferal biostratigraphy was used to constrain the ages of samples. Data obtained by these methods were combined with previous authors’ work to produce a synthesis map, unit correlations, and geological cross-sections of the Makara and Ruakokoputuna Valleys. Late Miocene-early Pliocene geological history is interpreted, and a depositional model is proposed to explain the presence of giant cross-beds in the Clay Creek Limestone.  Despite major differences in lithology, the Clay Creek Limestone and Bells Creek Mudstone are shown to be partially laterally equivalent, while the overlying Makara Greensand is shown to be a diachronous unit which ranges from late Miocene (Kapitean) to early Pliocene (Opoitian) in age. This revised stratigraphy raises questions about the current classification of the Palliser and Onoke Groups, and provides new insights into regional geological history. The late Miocene-early Pliocene stratigraphy records a history of regional subsidence, punctuated by episodes of deformation which caused localised uplift and erosion. Previous seismic imaging studies identified one such episode of accelerated crustal shortening and deformation in the Wairarapa region near the Miocene-Pliocene boundary. The Clay Creek Limestone has proven to be a useful marker horizon for constraining the timing and style of deformation, which is interpreted to have occurred prior to 7.2 Ma. Major differences in stratigraphy between the upthrown and downthrown sides of the Mangaopari Fault indicate that the fault was active during this deformational episode. Lithostratigraphic units from the study area have been correlated with units in other parts of the Wairarapa, and these correlations suggest that late Miocene deformation in the region may have propagated from south to north.</p>

Cannibalism of contourites by gravity flows: explanation of the facies distribution of the Ordovician Pingliang Formation along the southern margin of the Ordos Basin, China

2020 ◽  
Vol 57 (3) ◽  
pp. 331-347
Author(s):  
Hua Li ◽  
A.J. van Loon ◽  
Youbin He
Keyword(s):  
Ordos Basin ◽  
High Energy ◽  
Middle Part ◽  
Turbidity Currents ◽  
Middle Ordovician ◽  
Fine Grained ◽  
Southern Margin ◽  
Gravity Flows ◽  
Facies Associations ◽  
The Ordos Basin

The Late Ordovician Pingliang Formation accumulated along the southern margin of the Ordos Basin in China. The convergence of the Yangtze Plate and Sino-Korean Plate led to a trench–arc–basin system during the Middle Ordovician, with a platform- and slope-dominated setting in the east where a graben complicated the overall simple paleogeographical picture, relatively parallel zones of a platform and a slope setting in the middle, and a change from platform to slope to deep marine to a trench setting in the west. This configuration resulted in various types of gravity flow deposits and contourites with different compositions and pathways. The present study focuses on the typical characteristics of contourites in the geological record and the relationships between contour currents and gravity flows. The Pingliang Formation contains eleven lithofacies grouped into five facies associations. These facies associations represent deep sea autochthonous deposits, several types of debrites, turbidites, and contourites, as well as turbidites within which the fine-grained top portion was reworked by a contour current. The various lithofacies are concentrated in different parts of the study area: micritic contourites and debrites are concentrated in the eastern part; debrites, and sandstone and siltstone turbidites are concentrated in the middle part; and calcarenitic turbidites, contourites, and reworked turbidites occur in the western part. The main contour current ran parallel to the contour lines from east to west. Although most of the contour current continually moved westward in the eastern part of the study area, a minor part split off and followed a semicircular pathway through the Fuping Graben; its velocity became reduced here so that micritic contourites were deposited. The velocity of the contour current was increased locally when it entered a confined trough in the western part of the study area. The relatively high energy of the contour current here resulted in calcarenitic contourites. The velocity of the contour current was low where it ran through an open environment, resulting in fine-grained, thin contourites in the middle part of the study area. Large turbidity currents and debris flows occurred here, and their high energy destroyed almost all earlier deposited contourites. This explains why traces of contour currents in the middle part of the study are very scarce, although the east–west-running contour current must have passed through this area.

scholarly journals Facies Analysis of Eocene Sediment of Umuahia Area, Southeastern Nigeria

2019 ◽  
pp. 1-22
Author(s):  
A. C. Ezebunanwa ◽  
J. I. Eronin ◽  
V. Okorie ◽  
E. C. Mbagwu ◽  
Njoku Achu Uchenna
Keyword(s):  
Grain Size ◽  
Depositional Environment ◽  
Facies Analysis ◽  
Research Work ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Facies Association ◽  
Southeastern Nigeria ◽  
Kaolinite Clay ◽  
Fine Grained

This research work is the detailed facies analysis of the depositional environments and paleogeographic setting of the Eocene sedimentary sequence (Ameki Formations) exposed in the Umuahia area and paleoclimate during that periods. The study area was mainly concentrated around Amaudara inUmuahia South and Ekeoha in Umuahia North. And the co-ordinate are as follows,location-1 0.5°30.80N, 0.7°26.93E, location-2 0.5°30.39N, 0.7°26.62E, location-3 0.5° 32.83N, 0.7°27.24 E and location-4 0.5°32.19 N, 0.7°26.13 E. The aim of the study is to analyze the detailed sedimentary facies and describe the depositional environment in other to predict the depositional environment of the Eocene sediment (Ameki Formation) of the study area, which is underlain by rock unit of Ameki and predominately contains Laterite, mudstone, siltstone, claystone, sandstone and shale and Burrows were identified. The rock sequence consist of reddish lateritic material, highly weathered mudstone capped with ripped bedded kaolinite clay unit, light grey claystone, cross-bedded sandstone with claystone, whitish sandstone, siltystone, fine-medium grained sandstone with pockets of mudclast capped with ferruginized ground and dark grey shale. On the basis of gross lithology, sand-silt-clay percentage, color, texture and assemblage of sedimentary structure, eight distinct lithofacies type were recognized, grey shale facie (Gs), clay stone facie (Cs), cross-bedded sandstone facie (Cbs), mudstone facie (Mf), lateritic facie (Lf), mudstone facie (Bms), ferruginized sandstone facie (Fsf), sandstone facie (Bsf) are recognized within the lithosuccesion. From the analysis, the facies are grouped into two facie association on the basis of grain size. The Fine-grained facies association (FFA) which consist of Gs, Cbs, Cs, Mf and Fst and the Medium to Fine-grained facies association (MFA) which also consist of Bms, Bsf and Lf. It also shows medium grained sand, moderately sorted to well sorted sandstone, Skewness ranged from symmetrical to positive skewed and kurtosis showed leptokurtic. Deduction from facies analysis and grain size analysis shows that Ameki Formation consist of foraminifera and Mollusca which indicate that Ameki Formation was deposited in the estuarine(Marine) environment.

Thrust dissection control of deep-water clastic dispersal patterns in the Klematia–Paramythia foreland basin, western Greece

2000 ◽  
Vol 137 (6) ◽  
pp. 667-685 ◽  
Author(s):  
PAVLOS AVRAMIDIS ◽  
ABRAHAM ZELILIDIS ◽  
NIKOLAOS KONTOPOULOS
Keyword(s):  
Middle Eocene ◽  
Foreland Basin ◽  
Field Studies ◽  
Depositional Environments ◽  
Dispersal Patterns ◽  
Submarine Fans ◽  
Fine Grained ◽  
Thrust Front ◽  
Facies Associations ◽  
Western Greece

The Klematia–Paramythia basin is an internal part of the middle Ionian zone of the Hellenide orogen in western Greece. It consists of Middle Eocene to Late Miocene turbidites, up to 3300 m thick, which were deposited in a series of submarine fans. Field studies suggest that the configuration and the depositional environments of the basin were affected by two tectonic phases. During the first tectonic phase, in Middle Eocene to Late Oligocene times, a foreland basin was formed west of the Pindos Thrust front. During the second tectonic phase, in the Early Miocene, the Ionian zone (a part of the foreland basin) was subdivided by internal thrusting into three sub-basins (internal, middle and external) and changed to a complex type foreland basin. Comparison of the type and facies associations of the turbidite deposits that accumulated within the basin suggests that these two tectonic phases had a significant effect on sedimentary dispersal patterns. During the first tectonic phase in the Klematia–Paramythia basin (when it was part of the foreland basin), fine-grained turbidites, up to 1050 m thick, accumulated on the distal part of a submarine fan. The lower part (900 m thick) of these deposits consists of thin to thick interbedded sandstone/mudstone beds which are interpreted as lobes and lobe-fringe (outer-fan) deposits. The upper parts (150 m thick) of these deposits are composed of very thin to thin siltstone/mudstone beds, representing a basin plain environment. During the second tectonic phase, sediments up to 2260 m thick were deposited in the Klematia–Paramythia basin. These deposits are interpreted as lobes and lobe-fringe (outer-fan) fine-grained turbidites in the central part of the basin, channel and interchannel deposits (inner-fan) in some areas of the periphery of the basin, and shelf deposits in the northern and southern terminations of the basin.

scholarly journals Facies Analysis and Depositional Environments of the Late Palaeozoic Coal-Bearing Madzaringwe Formation in the Tshipise-Pafuri Basin, South Africa

ISRN Geology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ntokozo Malaza ◽  
Kuiwu Liu ◽  
Baojin Zhao
Keyword(s):  
South Africa ◽  
Flood Plain ◽  
Depositional Environments ◽  
Limpopo Province ◽  
Sequence Stratigraphic ◽  
Fine Grained ◽  
Lower Member ◽  
Late Palaeozoic ◽  
Facies Associations ◽  
Middle Member

The late Palaeozoic coal-bearing Madzaringwe Formation of the Karoo Supergroup in the Tshipise-Pafuri Basin in the Limpopo Province, South Africa, records part of the infill of a passive continental margin terrain. Lithofacies analysis was performed with a view to deduce the nature of depositional environments of the Formation. Sedimentological and sequence stratigraphic evidence indicates that this unit represents a complex siliciclastic facies that reflects a fluvial paleodepositional environment. Eleven facies, which were grouped into five facies associations, were recognised. The base of the Madzaringwe Formation (Lower Member) represents a sequence deposited by braided channels. The coal deposits represent flood plain and swamp deposits, which is characterised by shale, thick coal seams, siltstone, and sandstone. The Middle Member is characterised by both clast and matrix supported conglomerates, major tubular and lenticular sandstones, and finely calcareous, micaceous siltstone. The deposition represents a sequence being formed from fluvial and particularly braided channels. The crudely stratified, coarse to pebbly sandstone indicates channel lag deposits within a heavy loaded fluvial system. The fine-grained sandstone represents deposition by shift channel and side bar deposits during lower flow conditions. The Upper Member is characterised by facies associations similar to the Lower Member, representing a new depositional cyclothem.

scholarly journals Stratigraphic Investigations into the Late Miocene-Early Pliocene of the Northern Aorangi Range, Wairarapa

2021 ◽  
Author(s):  
◽  
Tamsin Lesley Beatrice Bertaud-Gandar
Keyword(s):  
Cross Sections ◽  
Late Miocene ◽  
High Energy ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Geological History ◽  
Early Pliocene ◽  
Lithostratigraphic Units ◽  
Uplift And Erosion

<p>The late Miocene-early Pliocene geology of the Makara and Ruakokoputuna Valleys in the northern Aorangi Range, south-east Wairarapa, is described in detail. In this area, a succession of Neogene sedimentary units laps onto basement rocks of Cretaceous age, and late Miocene-early Pliocene stratigraphy varies markedly, from bathyal mudstone to high energy coastal environments, over distances of only a few kilometres. Sections were measured at four key locations, which provided reference sites for stratigraphic changes across the study area. Additional detailed field mapping was carried out around Te Ahitaitai Ridge. Depositional environments were interpreted using grain size analysis, macrofossil and foraminiferal assemblages, and palynology. Foraminiferal biostratigraphy was used to constrain the ages of samples. Data obtained by these methods were combined with previous authors’ work to produce a synthesis map, unit correlations, and geological cross-sections of the Makara and Ruakokoputuna Valleys. Late Miocene-early Pliocene geological history is interpreted, and a depositional model is proposed to explain the presence of giant cross-beds in the Clay Creek Limestone.  Despite major differences in lithology, the Clay Creek Limestone and Bells Creek Mudstone are shown to be partially laterally equivalent, while the overlying Makara Greensand is shown to be a diachronous unit which ranges from late Miocene (Kapitean) to early Pliocene (Opoitian) in age. This revised stratigraphy raises questions about the current classification of the Palliser and Onoke Groups, and provides new insights into regional geological history. The late Miocene-early Pliocene stratigraphy records a history of regional subsidence, punctuated by episodes of deformation which caused localised uplift and erosion. Previous seismic imaging studies identified one such episode of accelerated crustal shortening and deformation in the Wairarapa region near the Miocene-Pliocene boundary. The Clay Creek Limestone has proven to be a useful marker horizon for constraining the timing and style of deformation, which is interpreted to have occurred prior to 7.2 Ma. Major differences in stratigraphy between the upthrown and downthrown sides of the Mangaopari Fault indicate that the fault was active during this deformational episode. Lithostratigraphic units from the study area have been correlated with units in other parts of the Wairarapa, and these correlations suggest that late Miocene deformation in the region may have propagated from south to north.</p>

Sign in / Sign up

Export Citation Format

Share Document