Early Cretaceous Palynofloras from Tarim Basin,Xinjiang

One hundred and eight species of fossil spores and pollen referred to 55 genera found from the Lower Cretaceous Kapushaliang (Kizilsu) Group in the Tarim Basin of Xinjiang have been studied in this paper. The Kapushaliang Group may be divided into the Yageliemu Formation, the Shushanhe Formation and Baxigai Formation in ascending order. The Yageliemu palynoflora is characterized by the predominance of gymnospermous pollen, the relative abundance of pteridophytic spores and the absence of angiospermous pollen. Coniferae is dominant, while Lygodiaceae and Schizaeaceae are important in the flora. The most common species of palynomorphs are Todisporites minor, Cicatricosisporites dorogensis, C. australiensis, Lygodiumsporites subsimplex, Schizaeoisporites cretacius, S. zizyphinus, S. certus. Cibotiumspora paradoxa, Cyathidites australis, C. minor, Biretisporites potoniael, Cycadopites minimus, Pseudowalchia hiangulina, Parvisaccites radiatus, Podocarpidites multesimus, P. canadensis, Alisporites bilateralis, Cedripites cretaceus, C. canadenris, Abietineaepollenites microalatus, Clarsopollis classoides, C annulatus, C. xinjiangensis (sp. nov.), Ephedripites multicostatus, E. tarimensis (sp. nov.), etc . The palynoflora is comparable with those of the lower part of the Lower Xinminbu Formation in northwestern China and the lower part of the Lower Mannville Formation in western Canada, which is considered corresponding from Berriasian to Valanginian in age. The Shushanhe palynoflora is also characterized by dominance of gymnosperms and subdominance of pteridophyta. Some primitive angiospermons pollen grains are found in the upper part of the formation. In addition to the most common species of the above mentioned palynoflora, the important species in the present palynoflora comprise Cicatricosisporites potomacensis, C. orbiculatus, C. subrotundus, Concavissimisporites punctatus, C. verrucosus, C. globosus, lmpardecispora apiverrucata, Trilobosporites crassus, T. trioreticulosus, Pilosisporites verus, P. trichopapillosus, Klukisporites pseudoreticulatus, Verrucosisporites obscurilaesuratur, Converrucosisporites saskatchewanensis, Foraminisporis wonthaggiensis, Cingulatisporites valdensis, C. ruginosus, Jiaohepollis verus, Pityosporites constrictus, etc. More than 40 in dicative species of Early Cretaceous occur in the assemblage. The palynoflora compares clcsely with those of the middle part of the Lower Xinminbu Formation and the Quartz Sand Member of the Lower Mannville Formatton. It is suggested that the Shushanhe Formation should belong to Hauterivian of Barremian in age. The Baxigai palynoflora is basically similar to the Shushanhe palynoflora. But the palynoflora shows an obvious increase in abundance of lygodiaceous spores and angiospermous pollen accompanied by a great reduction of Classopollis and Ephedripltes. Most of the Early Cretaceous species occurring in the above mentioned palynofloras are present. In addition, some Cretaceous species recorded from Aptian and Albian Stages in Europe, North America and Australia, such as Trilobosporites tribotrys, T. trioreticulosus, Coptospora paradoxa, Camarozonosporites insignis, Crybelosporites punctatus, etc., appear in the assemblage. In comparison with the microfloras of the upper part of the Lower Xinminbu Formation, the Upper Mannville Formation and the lower part of the Lower Colorado Group, the Baxigai Forma- tion should be referred to Aptian to Albian in age. Judging from the palynofloras, the early Cretaceous palaeoclimate in the basin should belong to the arid or semi-arid type of the subtropic zone. However, from Barremtan through Albian the climatic conditions might appear relatively wet.     

Fossil woods from Janggi Group (Early Miocene) in Pohang Basin,Korea

Sixty-four silicified fossil woods were collected from the Early Miocene Upper Coal-bearing Formation of Janggi Group in Pohang City, the Korean Peninsula. Out of them 23 specimens were identified as gymnosperms and 27 specimens as dicotyledons. The taxa identified include Picea palaeomaximowiczii Watari, Taxodioxylon cunninghamioides (Watari) Watari, T. sequoianum (Merckl.) Gothan, Fagus hondoensis (Watari) Watari, Cercidiphyllum sp., Camellia japonoxyla Suzuki et Terada, Distylium chiharu-hirayae Suzuki et Terada, Aesculus sp., Wataria miocenica (Watari) Terada et Suzuki and W. parvipora Terada et Suzuki. All of these species are reported for the first time from the Tertiary basins of Korea. Compared with those of the Miocene Formations in Japan, most taxa we found are common between the paleo-floras in Korea and Japan during the Early to Middle Miocene.     

Biodiversity and palaeoclimatic interpretation of Early Cretaceous flora of Jabalpur Formation, Satpura Basin, India

The Jabalpur Formation of Jabalpur series, named after Jabalpur city in Central India, is exposed along the Narbada River, in Satpura Basin. The series is divided into the lower Chaugan and the upper Jabalpur stages. The Jabalpur beds occur between Mahadevas and Lametas at Mahadeva Hills, exhibit highest Gondwanan strata, and embody diversified flora. These beds also extend laterally to Bairam and Belkher areas in western part of central India. The highest diversity of the floral assemblage is recorded in the central portion of the basin (Sehora and Hasnapur) whereas the lowest diversity is recorded in Morand River, Parsapani and Tilaksindoor areas. The diversity in floral assemblage indicates the dominance of conifers and pteridophytes along with cycadophytes and certain pteridosperms. The palynofloral assemblage from this formation contains pollen and spores of bryophytic, pteridophytic and gymnospermic groups. The palaeovegetational diversity, biostratigraphic correlation and phytogeographic distribution of the Jabalpur flora are discussed in comparison with various coeval floras of Indian peninsula along with contemporaneous deposits of the other Gondwanan regions. The palaeogeographic analysis suggests that the flora was thriving as mixed vegetation during Early Cretaceous under seasonally hot and dry or alternating with wet and dry condition.     

On the Evolution of the Palynoflora and Climatic Environment During Late Pleistocence in Tengger Desert,China

Palynoflora studies on the Duantouliang section, located at 39º40'N, 103º55'E in Northwestern Tengger Desert, China showed that, based on the spore-pollen assemblages, the major vegetation and climatic environment between 42 000 to 23 000 a BP could be divided into the following different periods: Ⅰ. From 42 000 to 38 000 a BP, the spore-pollen assemblages displayed that the mixed conifer/deciduous broad-leaved forests developed on the mountain and its foothill regions where the bare Gobi-desert are at present; At that time, Populus and Salix forests and grassland surrounded the Paleaolake, the climate condition was much warmer and humid than today; Ⅱ. From 38 000 to 37 000 a BP, the climate was warm and moist, it was the most suitable period for the plant growth, the studied area was dominated by the temperate and warm-temperate mixed broad-leaf deciduous and needleleaf forest, there was meadow spreaded on the river sides and lake beaches; Ⅲ. From 31 000 to 30000 a BP, the needleleaf forests and cold-temperate Salix oritrepha shrubs were flourishing, and the climate at that time was relatively cold;Ⅳ. From 30000 to 28000 a BP, the temperatures began increasing, the high lake levels was formed during this time, and the vegetations were meadows and swamps; V. From 28 000 to 23 000 a BP, temperate Cupressaceae and Betula mixed conifer/deciduous forests grew on mountain and foothill region, grassland developed on plain areas, Salix was on lake and river sides. This indicates a warm and moist climate condition but it was drier than the earliest period.     

Early Miocene vegetation and climate in Weichang District, North China

The Early Miocene palynological assemblage of Guangfayong (GFY) in the Weichang District, Hebei Province, China has been studied. It consists of 48 palynomorphs belonging to 39 families, with pollen and spores belonging to angiosperms (28.9%), gymnosperms (59.9%), ferns (10.8%) and other elements (0.5%). Based on the palynological assemblages of GFY and Wuluogong (WLG), another locality in the Weichang District, the Early Miocene vegetation of the Weichang District, was characterized by a mixed temperate forest of conifers (e.g. Pinus, Picea, Tsuga) and broad-leaved trees (e.g. Betula, Alnus), with some subtropical plants (e.g. Carya). The palaeoclimatic parameters of Guangfayong were obtained by applying the Coexistence Approach: the mean annual temperature from 7.8 to 14.9 °C, the difference of temperature between the coldest and warmest months from 14.2 to 23 °C, the mean temperature of the coldest month from − 3 to 5.9 °C, the mean temperature of the warmest month from 23.5 to 25.4 °C, the mean annual precipitation from 658.7 to 1389.4 mm, the minimum monthly precipitation from 7.6 to 16.4 mm, and the maximum monthly precipitation from 161.4 to 205.9 mm. It suggests a warm temperate to subtropical climate in Weichang District, similar to that of present-day Zhaojue City, Sichuan Province in the Yangtze River Valley. When the palaeoclimatic parameters were compared with those of Middle Miocene Shanwang Basin, it would seem that the temperature and precipitation were a little higher in the Middle Miocene of eastern China. However, if the latitudinal temperature gradient at that time is considered, the median temperature values of GFY of Early Miocene and Shanwang of Mid-Miocene were similar.     

Tissue parasitic helminthiases are prevalent at Cheongjin, North Korea

We investigated a small-scale serological survey to screen tissue-parasitic helminthiases of North Koreans as one of research programs for re-unification of Korea. Soil-transmitted helminthiases were found highly prevalent among North Korean residents at the border with China. ELISA using 4 tissue-parasitic helminth antigens was applied to 137 residents living in Cheongjin-shi, Hamgyeongbuk-do, North Korea and 133 female refugees in South Korea in 2004-2005. Among a total of 270 samples, 31 (11.5%), 25 (9.3%), and 11 (4.1%) were positive for specific IgG antibodies to antigens of Clonorchis sinensis, Taenia solium metacestode, and sparganum, respectively. The overall positive rate was 21.5%; 38.2% in males and 15.8% in females. The present finding suggests that tissue parasites, such as C. sinensis, T. solium metacestode and sparganum are highly prevalent in some limited areas of North Korea. These foodborne tissue-parasitic helminthiases should be considered for future control measures of parasitic diseases in North Korea.     

Cretaceous and Cenozoic non-marine deposits of the Northern South Yellow Sea Basin, offshore western Korea: palynostratigraphy and palaeoenvironments

Palynological analyses of two wells (Haema-1 and Kachi-1) located in two sub-basins of the Northern South Yellow Sea Basin have been carried out in order to establish a palynostratigraphic breakdown of the sedimentary succession and to determine environments of deposition. Seven assemblage zones and two assemblage subzones have been erected on the basis of frequency variations in, and occurrences of, biostratigraphically significant palynomorphs as follows: Classopollis-Ephedripites Assemblage Zone (AZ): Barremian-Albian; Alisporites-Aquilapollenites-Penetetrapites AZ, which is subdivided into an Alisporites-Rugubivesiculites Assemblage Subzone: Cenomanian-Lower Maastrichtian, and an Aquilapollenites-Penetetrapites Assemblage Subzone: Upper Maastrichtian; Momipites-Coryluspollenites AZ: Paleocene; Caryapollenites-Inaperturopollenites AZ: Lower-Middle Eocene; Quercoidites-Pinuspollenites AZ: Upper Eocene; Liquidambarpollenites-Fupingopollenites-Magnastriatites AZ: Lower-Middle Miocene; Graminidites-Persicarioipollis AZ: Pliocene. The depositional environments represented by the well sections are considered to have been generally fluvio-lacustrine, and the climate to have varied between semi-arid and wet, and subtropical and warm temperate, except during the Late Eocene and Pliocene when a cool-temperate climate prevailed. Six stages in the development of the sub-basins are recognised. These are: (1) initial stage of rift or pull-apart basin-formation during the Late Jurassic?-Cretaceous; (2) subsidence from the Paleocene to Middle Eocene; (3) alternation of uplift and subsidence in the Late Eocene; (4) synrift inversion and erosion through the Oligocene; (5) uplift during the Early Miocene; and (6) widespread subsidence from the Middle Miocene onwards apart from during the Early Pliocene when the region was subjected to uplift once more.     

Cretaceous Nonmarine Trace Fossils from the Hasandong and Jinju Formations of the Namhae Area,Kyongsangnamdo, Southeast Korea

Nonmarine strata of the Cretaceous Hasandong and Jinju formations of the Sindong Group of the Namhae area, Kyongsangnamdo, southeast Korea, contain relatively diverse and abundant ichnofaunas including domichnia, fodinichnia, pascichnia, and repichnia. These ichnofaunas are systematically described herein and three ichnocoenoses, namely the Skolithos, Palaeophycus, and Chondrites ichnocoenoses, are defined based on their paleoenvironmental occurrence. The Skolithos ichnocoenose characterizes tabular laminated sandstone facies deposited on fluvial channel levées. It is dominated by infaunally produced ichnotaxa, particularly Skolithos magnus Howell, Planolites montanus Richter and Chondrites isp. type A, with reduced numbers of Skolithos verticalis (Hall) Taenidium barretti (Bradshaw) and rare examples of Circulichnus montanus (Vyalov), Cochlichnus anguineus Hitchcock, Helminthopsis abeli Ksi??kiewicz, Helimthopsis hieroglyphica Wetzel and Bromley, Laevicyclus isp., Planolites beverleyensis (Billings), Skolithos isp., Spirodesmos isp., Thalassinoides suevicus (Rieth), and rhizoliths. The Palaeophycus ichnocoenose characterizes floodplain environments and occurs in purple mudstones and associated massive sandstone facies of crevasse-splay deposits and dark gray to green shale facies of abandoned channels. Palaeophycus tubularis Hall and Planolites montanus Richter are the most characteristic ichnotaxa, while Beaconites coronus (Frey, Pemberton and Fagerstrom), Planolites annularius Walcott, Skolithos magnus Howell, Thalassinoides paradoxicus (Woodward), and sauropod and ornithopod tracks also occur but in reduced numbers. The Chondrites ichnocoenose occurs in dark gray to black mudstones deposited in marginal lacustrine environments. It is dominated by Chondrites isp. type B. with associated Beaconites antarcticus Vyalov, Helminthopsis hieroglyphica, Palaeophycus tubularis, Skolithos magnus, Taenidium barretti, and Torrowangea rosei Webby. The three ichnocoenoses recognized herein cannot be satisfactorily assigned to currently defined nonmarine ichnofacies, suggesting that existing models of such ichnofacies are in need of additional refinement.     

First record of a complete giant theropod egg clutch from Upper Cretaceous deposits,South Korea

Here, we report the first occurrence of a complete Macroelongatoolithus clutch from outside of China. Excavated from Upper Cretaceous strata of Aphae-do in Shinan-gun, Jeollanam-do Province, South Korea, the clutch of 19 eggs is characterised by large, elongate, symmetrical eggs arranged in a single-layered ring-shaped clutch. Eggs are inclined towards the centre of the 2.3-m diameter clutch, and average 41.17 cm long and 15.58 cm wide. Of the 19 eggs, 8 clearly retain a paired configuration. This specimen represents only the second report of large theropod eggs from South Korea and is the most complete Macroelongatoolithus clutch known from the region to date. Eggshell microstructural features are consistent with Macroelongatoolithus xixiaensis (oofamily Elongatoolithidae), previously known only from Cenomanian strata of southeastern China. This first record of a giant theropod egg clutch, here assigned to M. xixiaensis, extends the stratigraphic and paleogeographic range of Macroelongatoolithus eggs and parent animals to include the Campanian of South Korea.     

Four newly recorded species of subfamily Olethreutinae (Lepidoptera: Tortricidae) from North Korea

Four species of the subfamily Olethreutinae based on the materials in the Hungarian Natural History Museum are added to the North Korean fauna: Ancylis melanostigma Kuznetsov, Ancylis sativa Liu, Eucoenogenes japonica Kawabe and Eucosma glebana (Snellen). Photographs of adults and genitalia are provided with brief comments on the distribution.     

The Paleocene-Eocene Palynoflora from the Tantou Basin in West Henan

On the basis of palynological data the Paleoeene-Eocene palynoflora from the Tantou Basin in west Itenan are divided into three sporo-pollen assemblages. They are given ill ascending order as follows: 1. The first assemblage (Dazhang Formation) characterized mainly by the predominance of palynoforms of Ulmaeeae anal various Proteaeeous pollen, being assigned to Late Paleoeene and indicating a dry-hot climate. 2. The second assemblage (Lower part of the Tantou Formation) marked by the presence of various Triporopollenites and Tricolporopollenites, belonging to the Early Eocene. A moist-hot climate is reflected. 3. The third assemblage (the Upper part of the Tantou Formation) represented by aboundant pollen grains of saeeated elements (consisting of Pinaeeae and Podocarpaeeae) and the occurrence of Aquilapollenites pollen which plays an important part in this assemblage. It is interpreted as belonging to the middle to early Eocene. The climate was moist and warm. As indicated by the sporo-polleu assemblage the present Paleoeene to Eocene flora in the whole phytoprovienee may belong to a flora transitional from western to eastern China. In this paper the distribution of Aquilapollenites pollen and its stratigraphicai significance are also discussed and it is considered that this kind of pollen distributed in the Paleoeene of China is eertainly not redeposited. At the same time, sonm palynoforms of certain significance for delimitation of Paleoeene and Eocene are provided.     

Early Cretaceous Angiosperms of the Yanji Basin,Jilin Province

An assemblage of fossil plants was discovered in the Yanji Basin, Jitin Province, consisting mainly of pterid0Phytes, gymnosperms and a few angiosperms. The present paper deals with the angiosperms only; They are: Rogersia angunifolia, Saliciphyllum longifoliurn, Sapindopsis magnifolia, Sterculophyllurn eleganurn, ,Ficophyllum, "Sassafras", Ranunculophyllum pinnatisectum sp. nov., Clernatites lanceolatus sp. nov., and the fruits Carpolithus brookensis, Carpolithus sp. gymnosperm Sequoia as well, all angiosperms having the morphological features of early angiosperms. Most of them are similar to the elements of the Potomac Group in North America and to some extent approach the fossil plants of Neocomian in Mongolia. This assemblage is manifestly different from the Albian flora of Kolyma River (URSS) and Portugal of Europe because of belonging to different stages. Thus, the age of the Dalazi Formation of Yanji Basin is tentatively ascribed to Aptian. The characteristics of this assemblage indicate that the floras of Eurasia and North America had been closely related during the early Mid-Cretaceous and that the early angiosperms were widely distributed in the North Hemisphere. Judging from the characteristics of this assemblage and the deposition, the authors speculate that in Northeast China the climate was warm and humid during the early Mid-Cretaceous.     

Protaxodioxylon from the Late Jurassic to Early Cretaceous Kota Formation,Pranhita-Godavari Basin,India

Paleontological Journal - The xylotomy of the silicified wood from the Late Jurassic to Early Cretaceous Kota Formation of the Pranhita-Godavari Basin is studied and its systematic affinity is...     

Sporo-Pollen Assemblages from Late Phase of Early Cretaceous in Minhe Basin

Plenty of sporo-pollen fossils were found from the Upper Subformation of Hekou Formation at Chaijiatai, Lanzhou of Gansu, Minhe Basin. The sporo-pollen assemblage of the upper stratum of the Upper Suhformation was named as Schizaeoisporites-Cicatricosisporites. It could be further divided into two subassemblages. The upper one was Classopollis-Schiza- eoisporites, and the lower one was Piceapollenites-Cicatricosisporites. By analysing the periods of the important species and genera in the assemblage and comparing with the known assemblages in various districts, the author cosidered that the geologic age of the assemblage was the late phase of Early Cretaceous (Aptian-Alhian). The age of the second subassemblage was later which was Albian. So far, the stratum where the sporo-pollen fossils assemblage were found was the uppermost one of the Lower Cretaceous that have been found in Minhe Basin.     

Morphometric analysis of Tremadocian (earliest Ordovician) kirkocystid mitrates (Echinodermata, Stylophora) from the Taebaeksan Basin, Korea

Abundant isolated remains of stylophoran echinoderms (cornutes and mitrates) are reported for the first time in the late Tremadocian (Asaphellus Zone) Tumugol Formation of Korea. Mitrate remains include numerous adorals of Kirkocystidae. Several new important anatomical features have been observed on these adorals, as an internal calcitic layer that is associated to s₂ and possibly also to the palmar complex. This observation suggests that the palmar complex would be present not only in mitrocystitid mitrates, but also in peltocystitids. For the first time, several morphometric analyses have been undertaken based on isolated kirkocystid adorals, so as to explore the morphological diversity displayed by Korean adorals, but also in order to compare their morphology with that of other Gondwanan kirkocystids. Morphometric analyses indicate the occurrence of two contrasted morphologies within Korean adorals (morphotypes A and B), and of three distinct morphologies within European and North African forms (“Anatifopsis”, “Balanocystites”, and “escandei” morphotypes). Comparison of Korean adorals with those from Europe and North Africa shows that: (1) morphotypes B and “Anatifopsis” are equivalent; consequently, the two Korean specimens referred to morphotype B are assigned to the genus Anatifopsis; (2) morphology of most Korean adorals, which belong to morphotype A, is clearly distinct from that of all other described kirkocystids from Europe and North Africa. The small size, juvenile morphology, and great morphological variability observed in the morphotype A of the Korean adorals are suggestive of possible heterochronic processes (peramorphosis).     

Six species of Tortricinae (Lepidoptera, Tortricidae) new to North Korea

Six species of Tortricinae based on the materials in the Hungarian Natural History Museum were added to the North Korean fauna: Aethes rectilineana (Caradja), Gynnidomorpha luridana (Gregson), G. permixtana (Denis & Shiffermüller), Alceris uniformis (Filipjev), Eana vetulana (Christoph) and Neocalyptis angustilineata (Walsingham). Photos of adults and the genitalia are provided with brief comments on the distribution.     

Early Cretaceous non‐marine Ostracoda from the North Falkland Basin,South Atlantic

Twenty‐seven species of well‐preserved and abundant Early Cretaceous non‐marine ostracod crustaceans were recovered from the North Falkland Basin. The assemblage is unusually diverse for a non‐marine palaeoenvironment and is sourced from cuttings samples collected during 2011 drilling of wells by Desire and Rockhopper Exploration, in the northern and southern areas of the basin. Ostracoda are entirely undocumented in published accounts from this basin, and all but one species appear to be new to science. For the new taxa, one new family (Alloiocyprideidae; type genus Hourcqia) is proposed and includes Hourcqia woodi sp. nov. Four new genera are erected: Falklandicypris gen. nov.; type species F. petrasaltata sp. nov., Gangamoncythere gen. nov.; type species G. colini sp. nov., Paraplesiocypridea gen. nov.; type species P. alloios sp. nov., and Musacchiocythere gen nov.; type species M. sarunata (Musacchio, 1978 ). Nine other species are described as new and are Falklandicypris desiderata, Clinocypris epacrus, Cypria poietes, Ilhasina? leiodermatus, Looneyellopsis tuberculatus, Theriosynoecum petasmathylacus, Theriosynoecum ballentae, Timiriasevia fluitans, and Vecticypris samesi. The remainder are left in open nomenclature due to paucity of material. The ostracod assemblage is largely restricted to the southern part of the basin (wells 25/5‐1 and 26/6‐1). In the northern part of the basin only four species, dominated by Vecticypris samesi, are present and with one possible exception are restricted there. There appears to have been little or no interchange of species suggesting that a barrier probably existed between the northern and southern regions. The more diverse southern assemblage indicates that more favourable conditions existed to the south. Stratigraphically, a distinct change in faunal composition recorded in both southern wells is likely to be an isochronous event correlatable across the southern area, and of an age no younger than Hauterivian.     

New hybodont shark assemblage from the Early Cretaceous of the Basque-Cantabrian Basin

Hybodont remains from the Early Cretaceous of the Basque-Cantabrian Basin (Cantabric Range) in the North of Spain are described for the first time. This assemblage represents a highly diversified shark fauna adapted to different feeding habits. Isolated remains of six hybodont genera, namely Hybodus, Egertonodus, Planohybodus, Lonchidion, Parvodus, and Lissodus, have been recovered and described from the freshwater Vega de Pas Formation in the locality of Vega de Pas (Cantabria, Northern Spain). Most of these taxa are known from the English Wealden, making the shark fauna of the Vega de Pas 1 site the most similar assemblage to English Wealden shark fauna among any other site known in Europe.     

Extramorphological Features of Sauropod Dinosaur Tracks in the Uhangri Formation (Cretaceous), Korea

Sauropod footprints in the Uhangri Formation (Cretaceous) of Korea exhibit an unusual pattern of morphology, with the interior of each print partitioned into a series of pockets by conspicuous radial crests. The crests are evidently extramorphological features and have been interpreted as upwellings of sediment extruded through the floor of the footprint following its fracture by impact of the trackmaker's foot. That explanation entails some inconsistencies, and an alternative explanation is proposed here. The alternative explanation envisages delamination of a superficial sheet of sediment that was lifted into a canopy, which subsequently collapsed in radiating folds. The superficial sheet of sediment might have been lifted by either or both of two mechanisms—by adhering to the underside of the trackmaker's foot or by being forced upward into a blister-like dome by the backflow of water previously displaced by impact of the trackmaker's foot. These alternative explanations draw attention to minor morphological features that were previously unexplained.