This report describes a study of the palynology of six samples from the archaeological site at Bu... more This report describes a study of the palynology of six samples from the archaeological site at Burrough Hill, south of Melton Mowbray in Leicestershire in order to determine the source of these materials. Foreword .
Since the publication of a major literature compilation issued in mid 2012, 94 further contributi... more Since the publication of a major literature compilation issued in mid 2012, 94 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued recently (i.e. during late 2012 and early 2013). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe, and are listed herein with a description of each item as a string of keywords.
Since the publication of five literature compilations issued between 2012 and 2020, 63 further pu... more Since the publication of five literature compilations issued between 2012 and 2020, 63 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued in the last 14 months (i.e. between February 2019 and March 2020). These studies are on North Africa, Southern Africa, East Arctic, West Arctic, east and west sub-Arctic Canada, China and Japan, East Europe, West Europe, the Middle East, and sub-Arctic Russia west of the Ural Mountains, plus multiregion studies and items with no geographical focus. The single-region studies are mostly focused on Africa, the Arctic, Europe and the Middle East. All the 63 publications are listed herein with doi numbers where applicable, and a description of each item as a string of keywords.
Bibliographical reference RIDING, JAMES B. 2004. A palynological investigation of the Oxford Clay... more Bibliographical reference RIDING, JAMES B. 2004. A palynological investigation of the Oxford Clay Formation and the Quaternary succession of Northamptonshire (Sheets 171 and 186). British Geological Survey Internal Report, IR/04/046. 14pp.
Since the publication of a major literature compilation issued in mid 2012, 94 further contributi... more Since the publication of a major literature compilation issued in mid 2012, 94 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued recently (i.e. during late 2012 and early 2013). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe, and are listed herein with a description of each item as a string of keywords.
The co-occurrence of ammonites with palynomorphs in the Athol Formation of the Tusk-1 and Tusk-2 ... more The co-occurrence of ammonites with palynomorphs in the Athol Formation of the Tusk-1 and Tusk-2 wells drilled in the offshore Carnarvon Basin, Western Australia confirms the Early Bajocian (Middle Jurassic) age of the Dissiliodinium caddaense dinoflagellate cyst Oppel Zone. The macrofaunas refine this Early Bajocian age to the early Laeviuscula Chronozone. A belemnite from the Tusk-1 well has a strontium isotope ( 87 Sr/ 86 Sr) ratio which is consistent with the biostratigraphical age. All the identifiable ammonites belong to Pseudotoites robiginosus (Crick). Pseudotoites is prominent in the Early Bajocian of the Indo-Pacific Realm, being known mainly from onshore Western Australia and the Southern Andes, together with rare occurrences in Irian Jaya (west New Guinea); somewhat surprisingly, it is also rarely present in southern Alaska. The palynofloras studied from the Tusk-1 and Tusk-2 wells contain abundant specimens of the marine dinoflagellate cyst Dissiliodinium caddaense, and are assigned to the Dissiliodinium caddaense Oppel Zone. The Athol Formation is a correlative of the Newmarracarra Limestone of onshore Western Australia; the distribution of both these units indicates a marine transgression onto the Australian block during the Early Bajocian.
Review of Palaeobotany and Palynology, Jun 1, 2012
Gonyaulacysta dentata is a very large and morphologically distinctive dinoflagellate cyst species... more Gonyaulacysta dentata is a very large and morphologically distinctive dinoflagellate cyst species which was first described from the Callovian (Middle Jurassic) strata of the Isle of Skye, northwest Scotland. The diagnosis and description of this species are emended herein in order to document the characteristic elongate pentagonal outline, the apicular structure, the bicavate cyst organisation, the prominent dorsal and lateral sutural crests which are typically denticulate, the discontinuous, low-relief midventral sutural ridges and the lack of a periarchaeopyle. Gonyaulacysta dentata is a reliable index taxon for the Late Callovian to earliest Oxfordian (Peltoceras athleta to Quenstedtoceras mariae zones) of the Boreal Realm and the Subboreal Province in the northern hemisphere. It is especially prominent in the Boreal Realm and the northern part of the Subboreal Province, and has been recorded from the Barents Sea region, arctic Canada, offshore Norway, the central and northern North Sea and northern Scotland. Typically this species represents a relatively low proportion of the overall dinoflagellate cyst assemblages. There are also reports of very rare specimens of Gonyaulacysta dentata from further south in the Northwest European Subprovince, i.e. France, Germany and Poland. It therefore appears to be a characteristic Boreal taxon, but low numbers migrated southwards into the Northwest European Subprovince due to a fall in palaeotemperatures during the Callovian-Oxfordian transition. The southwards expansion of this short-lived species parallels the southward migration of the Boreal ammonite family Cardioceratidae. There is a virtually mutually exclusive relationship between the Arctic species Gonyaulacysta dentata and the apparently warm-loving taxon Scriniodinium crystallinum during the Late Callovian to Early Oxfordian interval. This is consistent with the interpretation of Gonyaulacysta dentata as a cold water taxon.
Dinoflagellates and coccolithophores are two of the most important groups of phytoplankton in the... more Dinoflagellates and coccolithophores are two of the most important groups of phytoplankton in the modern oceans. These groups originated in the Triassic and radiated through the early Mesozoic, rising to ecological prominence. Within this long-term radiation, important shortterm intervals of evolutionary and ecological change can be recognised. The Bajocian (Middle Jurassic, ~170-168 Ma) was characterised by an important ecological transition within the coccolithophores, and the radiation of one of the principal families of cyst-forming dinoflagellates, the Gonyaulacaceae. During the Early Bajocian, the coccolith genus Watznaueria diversified and expanded ecologically to dominate coccolith floras, a situation which continued for the remainder of the Mesozoic. This pattern was paralleled within dinoflagellate cyst floras by the ecological dominance of the genus Dissiliodinium in the midpalaeolatitudes. These phenomena appear to be linked to a positive carbon isotope shift, and an interval of enhanced productivity driven by a shift to a more humid climate, enhanced continental weathering and nutrient flux. The latest Early Bajocian to earliest Bathonian was then characterised by the rapid increase in diversity of dinoflagellate cysts within the family Gonyaulacaceae. Through this interval, the Gonyaulacaceae transitioned from being a relatively minor component of dinoflagellate cyst floras, to becoming one of the prominent groups of cyst-forming dinoflagellates, which has persisted to the Holocene. In Europe, the pattern of this radiation was strongly influenced by sea level, with the increase in gonyaulacacean diversity reflecting a major second-order transgression. On a finer scale, the main pulses of first appearances correlate with third-order transgressive episodes. A rise in sea level, coupled with changes in the tectonic configuration of ocean gateways, appears to have controlled the pattern of plankton diversification in Europe. These palaeoceanographic changes may have enhanced water-mass transfer between Europe, the northwest Tethys Ocean and the Hispanic Corridor, which promoted the floral interchange of dinoflagellates. Whilst sea level rise and associated large-scale palaeoenvironmental shifts appear to have controlled the pattern of dinoflagellate cyst appearances in several regions outside Europe, there is no direct correlation between dinoflagellate cyst diversity and sea level rise on a global scale. Although the Bajocian was transgressive in several regions, widespread flooded continental area was also present throughout the preceding Aalenian, an interval of low gonyaulacacean diversity. Moreover, although the Middle Jurassic was an interval of major climatic cooling, there was a ~5 myr gap between the onset of cooling and the radiation of gonyaulacaceans during the Bajocian. The Bajocian was, however, marked by a major evolutionary radiation in the pelagic realm, including ammonites, giant suspension feeding fishes and planktonic foraminifera. These phenomena may indicate an underlying ecological driver to the radiation of dinoflagellates during the Bajocian evolutionary explosion which could represent an extension of the Mesozoic Marine Revolution.
We thank for his interesting discussion of the uplift rates derived from the Alport tufa and its ... more We thank for his interesting discussion of the uplift rates derived from the Alport tufa and its geomorphological setting. His comments highlight the tentative nature of geological approaches to determining rates of glacio-isostatic and tectonic uplift. In particular, Westaway (2012) questions the validity of the uplift rates that were presented within our original paper and we welcome the opportunity to clarify this further. We also welcome the opportunity to comment on the practicalities of determining uplift measurements from karst environments within the wider, long-term, tectonic evolution of the Peak District.
The preparation of palynomorphs for microscopy has traditionally used hydrochloric acid (HCl), hy... more The preparation of palynomorphs for microscopy has traditionally used hydrochloric acid (HCl), hydrofluoric acid (HF) and nitric acid (HNO 3 ). The use of these acids is both expensive and hazardous. An effective technique of preparation using sodium hexametaphosphate [(NaPO 3 ) 6 ] has been developed. The cleaned, crushed and softened sample is treated with (NaPO 3 ) 6 . The deflocculated clay is then sieved away and the residue centrifuged. This method has been successfully tested on seven Jurassic to Quaternary sample sets from the United Kingdom (UK) and Antarctica. In five of these sets, the rock/sediment was prepared using the mineral acid technique and the (NaPO 3 ) 6 procedure. Four of these five sample suites were prepared by both methods quantitatively, so that the concentrations of palynomorphs can be compared. The (NaPO 3 ) 6 method largely proved to be equally as effective as the mineral acid procedure. The Lower Toarcian Whitby Mudstone Formation of Leicestershire and the Middle and Upper Albian Gault Formation of Kent both produced similar palynomorph/kerogen associations. Some differences between the two procedures were, however, noted. The (NaPO 3 ) 6 method produced significantly better results than acid preparations for the uppermost Cretaceous (Maastrichtian) of Antarctica and the Pleistocene Till of northern England. By contrast, the majority of the samples from the in situ late Campanian-early Maastrichtian White Chalk Subgroup of north Norfolk prepared using HCl, were significantly richer in palynomorphs than those treated with (NaPO 3 ) 6.
Review of Palaeobotany and Palynology, Apr 1, 2022
The Middle-Late Jurassic dinoflagellate cyst genus Gonyaulacysta is highly distinctive, being cha... more The Middle-Late Jurassic dinoflagellate cyst genus Gonyaulacysta is highly distinctive, being characterized by an epicyst which is substantially larger than the hypocyst. The sulcal region is typically longitudinal, but relatively rare specimens with sigmoidal venters have also been observed. The latter morphotypes may represent experimentation with a novel morphological trait. Gonyaulacysta jurassica is the nomenclatural type, and occurs in the Oxfordian-Kimmeridgian and the Bathonian-Kimmeridgian in the Northern and Southern Hemispheres respectively. A total of 151 species have been assigned to Gonyaulacysta although 126 of these have been transferred to other genera. Prior to this contribution, 15 species were accepted; this is herein reduced to eight. The species that are accepted are:
A thermally mature palynomorph assemblage containing significant proportions of the characteristi... more A thermally mature palynomorph assemblage containing significant proportions of the characteristic dinoflagellate cyst Liasidium variabile Drugg 1978 was recovered from the Lower Jurassic Pabay Shale Formation of southwest Raasay. This is the first record of this biostratigraphically important species from the Jurassic of onshore Scotland. Liasidium variabile is a zonal index for the Late Sinemurian in northwest Europe, and this occurrence allows a correlation to the Oxynotum Zone of this substage. This is the first evidence for this chronozone on Raasay. Furthermore, the presence of morphotypes A and B of Liasidium variabile indicates a probable correlation to the Oxynotum Subzone of the Oxynotum Zone. This interpretation is not consistent with a hiatus within the Upper Sinemurian succession on Raasay.
Review of Palaeobotany and Palynology, Feb 1, 2019
The records of dinoflagellate cysts from the Late Triassic, the time during which they first appe... more The records of dinoflagellate cysts from the Late Triassic, the time during which they first appear abundantly in the geological record, are reviewed. Most of the Triassic palynological literature pertains to terrestrial palynomorphs, thus it is challenging to establish a global picture of the temporal and spatial distribution of Late Triassic dinoflagellate cyst around the supercontinent of Pangea. Moreover, data on Late Triassic dinoflagellate cysts are dispersed, and there are currently no records of dinoflagellate cysts from many marine successions. With the exception of an Australian record of the dinoflagellate cyst Sahulidinium ottii from the late Mid Triassic, and a possible early Carnian occurrence of, among others, Rhaetogonyaulax in the Swiss Alps, cyst-forming dinoflagellates first appeared relatively synchronously around Pangea from the late Carnian. There are three to six species of pre-Norian species globally, whereas species richness exceeded 25 by the end of the Norian. During the Rhaetian, marine seaways had gradually opened due to sustained continental breakup, allowing the expansion of dinoflagellates into many European basins. New species are present, some known only from restricted areas, whereas others like Dapcodinium appear to have a global distribution. The majority of Triassic dinoflagellate cyst taxa do not extend into the Jurassic.
Proceedings of the Yorkshire Geological Society, Apr 6, 2018
In the Burythorpe area of the Howardian Hills, located on the northern margin of the Market Weigh... more In the Burythorpe area of the Howardian Hills, located on the northern margin of the Market Weighton High, the Callovian succession is represented only by Lower Callovian sediments. These belong to the Kellaways Sand Member (Kellaways Formation), up to 12 m thick, but thinning southwards to 5 m. This contrasts with the more complete Callovian succession (Osgodby Formation) on the Yorkshire coast (Cleveland Basin) which is up to 32.5 m thick. At Burythorpe Quarry the Kellaways Sand Member has yielded palynomorphs and ammonites confirming an Early Callovian (Koenigi Zone) age with depositional hiatuses above and below. The sequence consists of a yellow-white, poorly cemented, fine-to medium grained, unimodal uncemented sand (moulding sand) with sparse grey clay beds and laminae, in marked contrast to the broadly coeval Red Cliff Rock Member (Osgodby Formation) of the Cleveland Basin. The depositional environment is interpreted as a tidally influenced shallow sea on the margin of the Market Weighton High, in a shallow sub-tidal regime, similar to the sub-
Since the publication of four compilations issued between 2012 and 2019, 93 further published con... more Since the publication of four compilations issued between 2012 and 2019, 93 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts from Africa, North America, South America, the Arctic, Australasia, East Europe, West Europe, the Middle East and Russia have been discovered in the literature, or were issued in the last 12 months (i.e. between February 2018 and January 2019). Of these, 55 were published during 2018 and 2019, making this period a very productive one. These studies are mostly on the Late Triassic and Early Jurassic of Europe. All the 93 items are listed herein with digital object identifier (doi) numbers where available, as well as a description of each item as a string of keywords. Publications on West Europe comprise 31.2% of the total, and items on Africa, the Arctic, Australasia, East Europe and Russia are also significant (15.1%, 6.5%, 7.5%, 9.7% and 14.0% respectively). The least wellrepresented regions are North America, South America and the Middle East (2.2%, 1.1% and 1.1% respectively). dinoflagellate cysts; earliest Cretaceous (Berriasian); Jurassic; literature analysis and compilation; Triassic; worldwide 1. et al. (2017), Londeix (2018) and Penaud et al. (2018). All dinoflagellate cysts and other palynomorph taxa at and below species level mentioned in this paper are listed in Appendix 2 of the Supplementary data with full author citations. This compilation includes 14 single-region contributions from East and North Africa, including five that are deemed especially significant (Appendix 1 of the Supplementary data). The highlights of this research are outlined in the next two subsections. In this synthesis, four single-region contributions on Ethiopia and Tanzania in East Africa are considered. Msaky ( ) is a thesis on the Bajocian to Cenomanian palynology of coastal Tanzania, and is available online. The thesis was published as Msaky (2011a, 2011b), and these major publications were reviewed by Riding (2019). The palynofloras of the Pindiro Group (Triassic to Lower Jurassic) of southern Tanzania were studied by Hudson and Nicholas (2014). These authors reported the dinoflagellate cysts Dapcodinium priscum, Sahulidinium ottii, Scriniocassis sp. cf. S. weberi and Sverdrupiella sp. from the Mbuo Formation (Hudson and Nicholas 2014, p. 59). This assemblage was interpreted as being Late Triassic in age. The presence of Dapcodinium priscum and Sverdrupiella sp. is consistent with this age determination. However, Sahulidinium ottii and Scriniocassis sp. cf. S. weberi are indicative of the Middle Triassic and the late Pliensbachian to Aalenian respectively (Helby et al. 1987, Riding and Thomas 1992). If confirmed, this report would be the first record of Sahulidinium ottii since this species was first described by Stover & Helby (1987). Nannoceratopsis pellucida was recorded from the Mihambia Formation by Hudson and Nicholas (2014, p. 65). The Mihambia Formation was interpreted as being Toarcian to Aalenian in age. Either the interpreted age, or the identification of Nannoceratopsis pellucida appears to be erroneous because the range base of this species in both hemispheres is Bathonian (Riding et al. 1985, Riding et al. 2010). It should be noted that the 'probable reworked dinoflagellate' figured by Hudson and Nicholas (2014, fig. 3.5M) is an indeterminate palynomorph, and has no demonstrable dinoflagellate affinity. Smelror et al. (2018) is a relatively short paper on the Upper Jurassic and Lower Cretaceous palynostratigraphy of the Kipatimu, Mitole, Nalwehe and Kihuluhulu formations 4 of the onshore Mandawa Basin in southeastern coastal Tanzania. The authors concluded that the four formations span the Oxfordian-Tithonian to Aptian-Albian interval. Jurassic and earliest Cretaceous dinoflagellate cysts were recorded only from the Mitole Formation, and these were interpreted as being of Oxfordian to Berriasian age. They include Canningia reticulata, Circulodinium distinctum, Cribroperidinium spp., Dingodinium jurassicum, Kaiwaradinium scruttinum and Systematophora areolata. This assemblage is significantly reminiscent of the Late Jurassic and Early Cretaceous of Gondwana (Helby et al. 1987, Riding et al. 2010). Sample WP232-5-14 from the Mitole Formation contains a marine palynoflora reminiscent to the Dingodinium jurassicum-Kilwacysta assemblage of Schrank (2005), and is indicative of a correlation with the Trigonia smeei Bed of Tendaguru Hill in southeastern Tanzania. Ten single-region contributions on North Africa are included herein. Nine of the articles are on northern Egyptian material, which reflects the intense hydrocarbon exploration and production activity in this region. One contribution (Jaydawi et al. 2016) is a study of Moroccan material. Aboul Ela and Tahoun (2010) documented the stratigraphical palynology of the Middle Jurassic to Lower Cretaceous (Bathonian-Callovian to Albian) of the Mango-1 and Til-1 offshore wells, northern Sinai, Egypt. Based on 174 samples of ditch cuttings, the authors established 11 informal dinoflagellate cyst zones which were correlated with other successions in Egypt and surrounding Tethyan areas. Five of these zones cover the Bathonian-Callovian to ?Berriasian interval. A major depositional hiatus between the late Kimmeridgian and the ?Berriasian was identified, and was attributed to a major sea-level fall associated with the Cimmerian orogenic event (Aboul Ela and Tahoun 2010, figs 2, 3). The samples yielded diverse and rich marine and terrestrial palynofloras. This paper focuses entirely on biostratigraphy, and the ranges of all the palynomorphs were given in nonquantitative range charts (Aboul Ela and Tahoun 2010, p. 90-98). The Jurassic dinoflagellate cyst associations appear to be substantially similar in content and distribution to their European counterparts; for example Cribroperidinium? longicorne, Ctenidodinium continuum, Gonyaulacysta jurassica, Korystocysta pachyderma and Systematophora areolata were recorded.
Since the publication of two literature compilations in 2012 and 2013, 89 further contributions o... more Since the publication of two literature compilations in 2012 and 2013, 89 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered or were issued recently (i.e. between April 2013 and March 2014). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe. They are all listed herein with digital object identifier (doi) numbers where applicable, and a description of each item as a string of keywords. The 15 most significant publications are briefly summarised.
This report comprises a palynological study of eight samples of the Jurassic succession from the ... more This report comprises a palynological study of eight samples of the Jurassic succession from the Bedford area. Foreword .
This report comprises a palynological study of 13 core samples from the Brent Group (Broom and Ne... more This report comprises a palynological study of 13 core samples from the Brent Group (Broom and Ness formations) of wells 211/28-H15 and 211/28-H1 (Hutton Field). Foreword .
Review of Palaeobotany and Palynology, Aug 1, 2017
Two samples were analysed from the lowermost Patasar Shale Member of the Patasar Tank section on ... more Two samples were analysed from the lowermost Patasar Shale Member of the Patasar Tank section on the western margin of the Wagad Uplift in the Kachchh Basin of Gujarat, western India. One of the samples produced an abundant, diverse and well-preserved palynobiota. The other sample produced a significantly sparser association, but of similar character. The overall assemblage is dominated by relatively long-ranging Jurassic gymnospermous pollen grains, but also includes dinoflagellate cysts of definite Gondwanan affinity. The dinoflagellate cysts are confidently correlated to the Australian Dingodinium swanense Interval Zone, which is of Kimmeridgian (Late Jurassic) age. This indicates that the Australasian Jurassic dinoflagellate cyst biostratigraphical scheme can be applied in western India, and probably throughout the Indian subcontinent. Due to evidence from ammonites and calcareous nannofossils in the Patasar Shale Member, allied with other biostratigraphical evidence from New Zealand and Papua New Guinea, the age of the Dingodinium swanense Interval Zone is reinterpreted as being of Early Kimmeridgian age. The Dingodinium swanense Interval Zone was previously assigned to the Early to Late Kimmeridgian. Its refinement and revision to an older age is entirely consistent with recent reassessments of these dinoflagellate cyst biozones.
This report describes a study of the palynology of six samples from the archaeological site at Bu... more This report describes a study of the palynology of six samples from the archaeological site at Burrough Hill, south of Melton Mowbray in Leicestershire in order to determine the source of these materials. Foreword .
Since the publication of a major literature compilation issued in mid 2012, 94 further contributi... more Since the publication of a major literature compilation issued in mid 2012, 94 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued recently (i.e. during late 2012 and early 2013). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe, and are listed herein with a description of each item as a string of keywords.
Since the publication of five literature compilations issued between 2012 and 2020, 63 further pu... more Since the publication of five literature compilations issued between 2012 and 2020, 63 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued in the last 14 months (i.e. between February 2019 and March 2020). These studies are on North Africa, Southern Africa, East Arctic, West Arctic, east and west sub-Arctic Canada, China and Japan, East Europe, West Europe, the Middle East, and sub-Arctic Russia west of the Ural Mountains, plus multiregion studies and items with no geographical focus. The single-region studies are mostly focused on Africa, the Arctic, Europe and the Middle East. All the 63 publications are listed herein with doi numbers where applicable, and a description of each item as a string of keywords.
Bibliographical reference RIDING, JAMES B. 2004. A palynological investigation of the Oxford Clay... more Bibliographical reference RIDING, JAMES B. 2004. A palynological investigation of the Oxford Clay Formation and the Quaternary succession of Northamptonshire (Sheets 171 and 186). British Geological Survey Internal Report, IR/04/046. 14pp.
Since the publication of a major literature compilation issued in mid 2012, 94 further contributi... more Since the publication of a major literature compilation issued in mid 2012, 94 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered, or were issued recently (i.e. during late 2012 and early 2013). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe, and are listed herein with a description of each item as a string of keywords.
The co-occurrence of ammonites with palynomorphs in the Athol Formation of the Tusk-1 and Tusk-2 ... more The co-occurrence of ammonites with palynomorphs in the Athol Formation of the Tusk-1 and Tusk-2 wells drilled in the offshore Carnarvon Basin, Western Australia confirms the Early Bajocian (Middle Jurassic) age of the Dissiliodinium caddaense dinoflagellate cyst Oppel Zone. The macrofaunas refine this Early Bajocian age to the early Laeviuscula Chronozone. A belemnite from the Tusk-1 well has a strontium isotope ( 87 Sr/ 86 Sr) ratio which is consistent with the biostratigraphical age. All the identifiable ammonites belong to Pseudotoites robiginosus (Crick). Pseudotoites is prominent in the Early Bajocian of the Indo-Pacific Realm, being known mainly from onshore Western Australia and the Southern Andes, together with rare occurrences in Irian Jaya (west New Guinea); somewhat surprisingly, it is also rarely present in southern Alaska. The palynofloras studied from the Tusk-1 and Tusk-2 wells contain abundant specimens of the marine dinoflagellate cyst Dissiliodinium caddaense, and are assigned to the Dissiliodinium caddaense Oppel Zone. The Athol Formation is a correlative of the Newmarracarra Limestone of onshore Western Australia; the distribution of both these units indicates a marine transgression onto the Australian block during the Early Bajocian.
Review of Palaeobotany and Palynology, Jun 1, 2012
Gonyaulacysta dentata is a very large and morphologically distinctive dinoflagellate cyst species... more Gonyaulacysta dentata is a very large and morphologically distinctive dinoflagellate cyst species which was first described from the Callovian (Middle Jurassic) strata of the Isle of Skye, northwest Scotland. The diagnosis and description of this species are emended herein in order to document the characteristic elongate pentagonal outline, the apicular structure, the bicavate cyst organisation, the prominent dorsal and lateral sutural crests which are typically denticulate, the discontinuous, low-relief midventral sutural ridges and the lack of a periarchaeopyle. Gonyaulacysta dentata is a reliable index taxon for the Late Callovian to earliest Oxfordian (Peltoceras athleta to Quenstedtoceras mariae zones) of the Boreal Realm and the Subboreal Province in the northern hemisphere. It is especially prominent in the Boreal Realm and the northern part of the Subboreal Province, and has been recorded from the Barents Sea region, arctic Canada, offshore Norway, the central and northern North Sea and northern Scotland. Typically this species represents a relatively low proportion of the overall dinoflagellate cyst assemblages. There are also reports of very rare specimens of Gonyaulacysta dentata from further south in the Northwest European Subprovince, i.e. France, Germany and Poland. It therefore appears to be a characteristic Boreal taxon, but low numbers migrated southwards into the Northwest European Subprovince due to a fall in palaeotemperatures during the Callovian-Oxfordian transition. The southwards expansion of this short-lived species parallels the southward migration of the Boreal ammonite family Cardioceratidae. There is a virtually mutually exclusive relationship between the Arctic species Gonyaulacysta dentata and the apparently warm-loving taxon Scriniodinium crystallinum during the Late Callovian to Early Oxfordian interval. This is consistent with the interpretation of Gonyaulacysta dentata as a cold water taxon.
Dinoflagellates and coccolithophores are two of the most important groups of phytoplankton in the... more Dinoflagellates and coccolithophores are two of the most important groups of phytoplankton in the modern oceans. These groups originated in the Triassic and radiated through the early Mesozoic, rising to ecological prominence. Within this long-term radiation, important shortterm intervals of evolutionary and ecological change can be recognised. The Bajocian (Middle Jurassic, ~170-168 Ma) was characterised by an important ecological transition within the coccolithophores, and the radiation of one of the principal families of cyst-forming dinoflagellates, the Gonyaulacaceae. During the Early Bajocian, the coccolith genus Watznaueria diversified and expanded ecologically to dominate coccolith floras, a situation which continued for the remainder of the Mesozoic. This pattern was paralleled within dinoflagellate cyst floras by the ecological dominance of the genus Dissiliodinium in the midpalaeolatitudes. These phenomena appear to be linked to a positive carbon isotope shift, and an interval of enhanced productivity driven by a shift to a more humid climate, enhanced continental weathering and nutrient flux. The latest Early Bajocian to earliest Bathonian was then characterised by the rapid increase in diversity of dinoflagellate cysts within the family Gonyaulacaceae. Through this interval, the Gonyaulacaceae transitioned from being a relatively minor component of dinoflagellate cyst floras, to becoming one of the prominent groups of cyst-forming dinoflagellates, which has persisted to the Holocene. In Europe, the pattern of this radiation was strongly influenced by sea level, with the increase in gonyaulacacean diversity reflecting a major second-order transgression. On a finer scale, the main pulses of first appearances correlate with third-order transgressive episodes. A rise in sea level, coupled with changes in the tectonic configuration of ocean gateways, appears to have controlled the pattern of plankton diversification in Europe. These palaeoceanographic changes may have enhanced water-mass transfer between Europe, the northwest Tethys Ocean and the Hispanic Corridor, which promoted the floral interchange of dinoflagellates. Whilst sea level rise and associated large-scale palaeoenvironmental shifts appear to have controlled the pattern of dinoflagellate cyst appearances in several regions outside Europe, there is no direct correlation between dinoflagellate cyst diversity and sea level rise on a global scale. Although the Bajocian was transgressive in several regions, widespread flooded continental area was also present throughout the preceding Aalenian, an interval of low gonyaulacacean diversity. Moreover, although the Middle Jurassic was an interval of major climatic cooling, there was a ~5 myr gap between the onset of cooling and the radiation of gonyaulacaceans during the Bajocian. The Bajocian was, however, marked by a major evolutionary radiation in the pelagic realm, including ammonites, giant suspension feeding fishes and planktonic foraminifera. These phenomena may indicate an underlying ecological driver to the radiation of dinoflagellates during the Bajocian evolutionary explosion which could represent an extension of the Mesozoic Marine Revolution.
We thank for his interesting discussion of the uplift rates derived from the Alport tufa and its ... more We thank for his interesting discussion of the uplift rates derived from the Alport tufa and its geomorphological setting. His comments highlight the tentative nature of geological approaches to determining rates of glacio-isostatic and tectonic uplift. In particular, Westaway (2012) questions the validity of the uplift rates that were presented within our original paper and we welcome the opportunity to clarify this further. We also welcome the opportunity to comment on the practicalities of determining uplift measurements from karst environments within the wider, long-term, tectonic evolution of the Peak District.
The preparation of palynomorphs for microscopy has traditionally used hydrochloric acid (HCl), hy... more The preparation of palynomorphs for microscopy has traditionally used hydrochloric acid (HCl), hydrofluoric acid (HF) and nitric acid (HNO 3 ). The use of these acids is both expensive and hazardous. An effective technique of preparation using sodium hexametaphosphate [(NaPO 3 ) 6 ] has been developed. The cleaned, crushed and softened sample is treated with (NaPO 3 ) 6 . The deflocculated clay is then sieved away and the residue centrifuged. This method has been successfully tested on seven Jurassic to Quaternary sample sets from the United Kingdom (UK) and Antarctica. In five of these sets, the rock/sediment was prepared using the mineral acid technique and the (NaPO 3 ) 6 procedure. Four of these five sample suites were prepared by both methods quantitatively, so that the concentrations of palynomorphs can be compared. The (NaPO 3 ) 6 method largely proved to be equally as effective as the mineral acid procedure. The Lower Toarcian Whitby Mudstone Formation of Leicestershire and the Middle and Upper Albian Gault Formation of Kent both produced similar palynomorph/kerogen associations. Some differences between the two procedures were, however, noted. The (NaPO 3 ) 6 method produced significantly better results than acid preparations for the uppermost Cretaceous (Maastrichtian) of Antarctica and the Pleistocene Till of northern England. By contrast, the majority of the samples from the in situ late Campanian-early Maastrichtian White Chalk Subgroup of north Norfolk prepared using HCl, were significantly richer in palynomorphs than those treated with (NaPO 3 ) 6.
Review of Palaeobotany and Palynology, Apr 1, 2022
The Middle-Late Jurassic dinoflagellate cyst genus Gonyaulacysta is highly distinctive, being cha... more The Middle-Late Jurassic dinoflagellate cyst genus Gonyaulacysta is highly distinctive, being characterized by an epicyst which is substantially larger than the hypocyst. The sulcal region is typically longitudinal, but relatively rare specimens with sigmoidal venters have also been observed. The latter morphotypes may represent experimentation with a novel morphological trait. Gonyaulacysta jurassica is the nomenclatural type, and occurs in the Oxfordian-Kimmeridgian and the Bathonian-Kimmeridgian in the Northern and Southern Hemispheres respectively. A total of 151 species have been assigned to Gonyaulacysta although 126 of these have been transferred to other genera. Prior to this contribution, 15 species were accepted; this is herein reduced to eight. The species that are accepted are:
A thermally mature palynomorph assemblage containing significant proportions of the characteristi... more A thermally mature palynomorph assemblage containing significant proportions of the characteristic dinoflagellate cyst Liasidium variabile Drugg 1978 was recovered from the Lower Jurassic Pabay Shale Formation of southwest Raasay. This is the first record of this biostratigraphically important species from the Jurassic of onshore Scotland. Liasidium variabile is a zonal index for the Late Sinemurian in northwest Europe, and this occurrence allows a correlation to the Oxynotum Zone of this substage. This is the first evidence for this chronozone on Raasay. Furthermore, the presence of morphotypes A and B of Liasidium variabile indicates a probable correlation to the Oxynotum Subzone of the Oxynotum Zone. This interpretation is not consistent with a hiatus within the Upper Sinemurian succession on Raasay.
Review of Palaeobotany and Palynology, Feb 1, 2019
The records of dinoflagellate cysts from the Late Triassic, the time during which they first appe... more The records of dinoflagellate cysts from the Late Triassic, the time during which they first appear abundantly in the geological record, are reviewed. Most of the Triassic palynological literature pertains to terrestrial palynomorphs, thus it is challenging to establish a global picture of the temporal and spatial distribution of Late Triassic dinoflagellate cyst around the supercontinent of Pangea. Moreover, data on Late Triassic dinoflagellate cysts are dispersed, and there are currently no records of dinoflagellate cysts from many marine successions. With the exception of an Australian record of the dinoflagellate cyst Sahulidinium ottii from the late Mid Triassic, and a possible early Carnian occurrence of, among others, Rhaetogonyaulax in the Swiss Alps, cyst-forming dinoflagellates first appeared relatively synchronously around Pangea from the late Carnian. There are three to six species of pre-Norian species globally, whereas species richness exceeded 25 by the end of the Norian. During the Rhaetian, marine seaways had gradually opened due to sustained continental breakup, allowing the expansion of dinoflagellates into many European basins. New species are present, some known only from restricted areas, whereas others like Dapcodinium appear to have a global distribution. The majority of Triassic dinoflagellate cyst taxa do not extend into the Jurassic.
Proceedings of the Yorkshire Geological Society, Apr 6, 2018
In the Burythorpe area of the Howardian Hills, located on the northern margin of the Market Weigh... more In the Burythorpe area of the Howardian Hills, located on the northern margin of the Market Weighton High, the Callovian succession is represented only by Lower Callovian sediments. These belong to the Kellaways Sand Member (Kellaways Formation), up to 12 m thick, but thinning southwards to 5 m. This contrasts with the more complete Callovian succession (Osgodby Formation) on the Yorkshire coast (Cleveland Basin) which is up to 32.5 m thick. At Burythorpe Quarry the Kellaways Sand Member has yielded palynomorphs and ammonites confirming an Early Callovian (Koenigi Zone) age with depositional hiatuses above and below. The sequence consists of a yellow-white, poorly cemented, fine-to medium grained, unimodal uncemented sand (moulding sand) with sparse grey clay beds and laminae, in marked contrast to the broadly coeval Red Cliff Rock Member (Osgodby Formation) of the Cleveland Basin. The depositional environment is interpreted as a tidally influenced shallow sea on the margin of the Market Weighton High, in a shallow sub-tidal regime, similar to the sub-
Since the publication of four compilations issued between 2012 and 2019, 93 further published con... more Since the publication of four compilations issued between 2012 and 2019, 93 further published contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts from Africa, North America, South America, the Arctic, Australasia, East Europe, West Europe, the Middle East and Russia have been discovered in the literature, or were issued in the last 12 months (i.e. between February 2018 and January 2019). Of these, 55 were published during 2018 and 2019, making this period a very productive one. These studies are mostly on the Late Triassic and Early Jurassic of Europe. All the 93 items are listed herein with digital object identifier (doi) numbers where available, as well as a description of each item as a string of keywords. Publications on West Europe comprise 31.2% of the total, and items on Africa, the Arctic, Australasia, East Europe and Russia are also significant (15.1%, 6.5%, 7.5%, 9.7% and 14.0% respectively). The least wellrepresented regions are North America, South America and the Middle East (2.2%, 1.1% and 1.1% respectively). dinoflagellate cysts; earliest Cretaceous (Berriasian); Jurassic; literature analysis and compilation; Triassic; worldwide 1. et al. (2017), Londeix (2018) and Penaud et al. (2018). All dinoflagellate cysts and other palynomorph taxa at and below species level mentioned in this paper are listed in Appendix 2 of the Supplementary data with full author citations. This compilation includes 14 single-region contributions from East and North Africa, including five that are deemed especially significant (Appendix 1 of the Supplementary data). The highlights of this research are outlined in the next two subsections. In this synthesis, four single-region contributions on Ethiopia and Tanzania in East Africa are considered. Msaky ( ) is a thesis on the Bajocian to Cenomanian palynology of coastal Tanzania, and is available online. The thesis was published as Msaky (2011a, 2011b), and these major publications were reviewed by Riding (2019). The palynofloras of the Pindiro Group (Triassic to Lower Jurassic) of southern Tanzania were studied by Hudson and Nicholas (2014). These authors reported the dinoflagellate cysts Dapcodinium priscum, Sahulidinium ottii, Scriniocassis sp. cf. S. weberi and Sverdrupiella sp. from the Mbuo Formation (Hudson and Nicholas 2014, p. 59). This assemblage was interpreted as being Late Triassic in age. The presence of Dapcodinium priscum and Sverdrupiella sp. is consistent with this age determination. However, Sahulidinium ottii and Scriniocassis sp. cf. S. weberi are indicative of the Middle Triassic and the late Pliensbachian to Aalenian respectively (Helby et al. 1987, Riding and Thomas 1992). If confirmed, this report would be the first record of Sahulidinium ottii since this species was first described by Stover & Helby (1987). Nannoceratopsis pellucida was recorded from the Mihambia Formation by Hudson and Nicholas (2014, p. 65). The Mihambia Formation was interpreted as being Toarcian to Aalenian in age. Either the interpreted age, or the identification of Nannoceratopsis pellucida appears to be erroneous because the range base of this species in both hemispheres is Bathonian (Riding et al. 1985, Riding et al. 2010). It should be noted that the 'probable reworked dinoflagellate' figured by Hudson and Nicholas (2014, fig. 3.5M) is an indeterminate palynomorph, and has no demonstrable dinoflagellate affinity. Smelror et al. (2018) is a relatively short paper on the Upper Jurassic and Lower Cretaceous palynostratigraphy of the Kipatimu, Mitole, Nalwehe and Kihuluhulu formations 4 of the onshore Mandawa Basin in southeastern coastal Tanzania. The authors concluded that the four formations span the Oxfordian-Tithonian to Aptian-Albian interval. Jurassic and earliest Cretaceous dinoflagellate cysts were recorded only from the Mitole Formation, and these were interpreted as being of Oxfordian to Berriasian age. They include Canningia reticulata, Circulodinium distinctum, Cribroperidinium spp., Dingodinium jurassicum, Kaiwaradinium scruttinum and Systematophora areolata. This assemblage is significantly reminiscent of the Late Jurassic and Early Cretaceous of Gondwana (Helby et al. 1987, Riding et al. 2010). Sample WP232-5-14 from the Mitole Formation contains a marine palynoflora reminiscent to the Dingodinium jurassicum-Kilwacysta assemblage of Schrank (2005), and is indicative of a correlation with the Trigonia smeei Bed of Tendaguru Hill in southeastern Tanzania. Ten single-region contributions on North Africa are included herein. Nine of the articles are on northern Egyptian material, which reflects the intense hydrocarbon exploration and production activity in this region. One contribution (Jaydawi et al. 2016) is a study of Moroccan material. Aboul Ela and Tahoun (2010) documented the stratigraphical palynology of the Middle Jurassic to Lower Cretaceous (Bathonian-Callovian to Albian) of the Mango-1 and Til-1 offshore wells, northern Sinai, Egypt. Based on 174 samples of ditch cuttings, the authors established 11 informal dinoflagellate cyst zones which were correlated with other successions in Egypt and surrounding Tethyan areas. Five of these zones cover the Bathonian-Callovian to ?Berriasian interval. A major depositional hiatus between the late Kimmeridgian and the ?Berriasian was identified, and was attributed to a major sea-level fall associated with the Cimmerian orogenic event (Aboul Ela and Tahoun 2010, figs 2, 3). The samples yielded diverse and rich marine and terrestrial palynofloras. This paper focuses entirely on biostratigraphy, and the ranges of all the palynomorphs were given in nonquantitative range charts (Aboul Ela and Tahoun 2010, p. 90-98). The Jurassic dinoflagellate cyst associations appear to be substantially similar in content and distribution to their European counterparts; for example Cribroperidinium? longicorne, Ctenidodinium continuum, Gonyaulacysta jurassica, Korystocysta pachyderma and Systematophora areolata were recorded.
Since the publication of two literature compilations in 2012 and 2013, 89 further contributions o... more Since the publication of two literature compilations in 2012 and 2013, 89 further contributions on Triassic, Jurassic and earliest Cretaceous (Berriasian) dinoflagellate cysts have been discovered or were issued recently (i.e. between April 2013 and March 2014). These studies are mostly on the Late Jurassic and Early Cretaceous of Europe. They are all listed herein with digital object identifier (doi) numbers where applicable, and a description of each item as a string of keywords. The 15 most significant publications are briefly summarised.
This report comprises a palynological study of eight samples of the Jurassic succession from the ... more This report comprises a palynological study of eight samples of the Jurassic succession from the Bedford area. Foreword .
This report comprises a palynological study of 13 core samples from the Brent Group (Broom and Ne... more This report comprises a palynological study of 13 core samples from the Brent Group (Broom and Ness formations) of wells 211/28-H15 and 211/28-H1 (Hutton Field). Foreword .
Review of Palaeobotany and Palynology, Aug 1, 2017
Two samples were analysed from the lowermost Patasar Shale Member of the Patasar Tank section on ... more Two samples were analysed from the lowermost Patasar Shale Member of the Patasar Tank section on the western margin of the Wagad Uplift in the Kachchh Basin of Gujarat, western India. One of the samples produced an abundant, diverse and well-preserved palynobiota. The other sample produced a significantly sparser association, but of similar character. The overall assemblage is dominated by relatively long-ranging Jurassic gymnospermous pollen grains, but also includes dinoflagellate cysts of definite Gondwanan affinity. The dinoflagellate cysts are confidently correlated to the Australian Dingodinium swanense Interval Zone, which is of Kimmeridgian (Late Jurassic) age. This indicates that the Australasian Jurassic dinoflagellate cyst biostratigraphical scheme can be applied in western India, and probably throughout the Indian subcontinent. Due to evidence from ammonites and calcareous nannofossils in the Patasar Shale Member, allied with other biostratigraphical evidence from New Zealand and Papua New Guinea, the age of the Dingodinium swanense Interval Zone is reinterpreted as being of Early Kimmeridgian age. The Dingodinium swanense Interval Zone was previously assigned to the Early to Late Kimmeridgian. Its refinement and revision to an older age is entirely consistent with recent reassessments of these dinoflagellate cyst biozones.
The Toarcian Oceanic Anoxic Event (T-OAE) in the Lusitanian Basin, western Portugal, was studied ... more The Toarcian Oceanic Anoxic Event (T-OAE) in the Lusitanian Basin, western Portugal, was studied in terms of the dinoflagellate response. Three localities, Peniche (the Toarcian GSSP), Maria Pares and Vale das Fontes were sampled. The material spans the Dactylioceras polymorphum, Hildaites levisoni and Hildoceras bifrons ammonite biozones. The taxa encountered were Mancodinium semitabulatum, Mendicodinium microscabratum, Mendicodinium spinosum subsp. spinosum, Mendicodinium sp., Nannoceratopsis ambonis, Nannoceratopsis gracilis, Nannoceratopsis senex and Sriniocassis weberi. The samples produced relatively low diversity dinoflagellate cyst floras which are typical of those from coeval European successions. The most abundant species is Luehndea spinosa. Dinoflagellate cysts typically dominate throughout the Dactylioceras polymorphum ammonite biozone; they significantly decreased in relative proportions after the T-OAE in the overlying Hildaites levisoni and Hildoceras bifrons ammonite biozones. The T-OAE in the Lusitanian Basin is characterised by a sudden decline in dinoflagellate cyst abundance and diversity. During and following the T-OAE, Mancodinium semitabulatum and Mendicodinium spp. were the only dinoflagellate cysts recorded. In the Lusitanian Basin, the T-OAE caused the extinction of Luehndea spinosa in the lowermost Hildaites levisoni ammonite biozone. This bioevent and the general 'blackout' of dinoflagellate cysts during the T-OAE, and their low recovery following the event, are indicative that dinoflagellate populations were responding to a major palaeoenvironmental change.
Uploads
Papers by James B Riding