Hanson Formation
{{Short description|Geological formation in Ross Dependency, Antarctica}}
{{Infobox rockunit
| name = Hanson Formation
| image = View of the Transantarctic Mountains.jpg
| caption = The Hanson Formation is located in the Transantarctic Mountains
| type = Geological formation
| age = Middle Sinemurian-Early Pliensbachian
~{{Fossilrange|194.6|188.5}}{{cite journal |last1=Bomfleur |first1=B. |last2=Blomenkemper |first2=P. |last3=Kerp |first3=H. |last4=McLoughlin |first4=S. |title=Polar regions of the Mesozoic–Paleogene greenhouse world as refugia for relict plant groups |journal=Transformative Paleobotany |date=2018 |volume=15 |issue=1 |pages=593–611 |doi=10.1016/B978-0-12-813012-4.00024-3 |url=https://www.diva-portal.org/smash/get/diva2:1257996/FULLTEXT01.pdf |access-date=13 February 2022}}
| period = Early Jurassic
| prilithology = Sandstone, tuffite
| otherlithology = Climbing-ripple lamination, horizontal lamination, and accumulations of clay-gall rip-up clasts
| namedfor = The Hanson Spur
| namedby = David Elliot
| region = Mount Kirkpatrick, Beardmore Glacier
| country = Ross Dependency
| coordinates = {{coord|84.3|S|166.5|E|source:wikidata|display=inline,title}}
| paleocoordinates = {{coord|57.5|S|35.5|E|display=inline}}
| unitof = Victoria Group
| subunits = Three informal members
| underlies = Prebble Formation
| overlies = Falla Formation
| thickness = {{convert|237.5|m|ft|abbr=on}}
| extent =
| area =
| map = {{Location map+ | Antarctica
| relief = 1
| width = 250
| float = center
| places =
{{Location map~ | Antarctica
| lat_deg = -84.3
| lon_deg = 166.5
| mark = Blue pog.svg
| marksize = 12
}}
}}
| map_caption =
}}
The Hanson Formation (also known as the Shafer Peak Formation) is a geologic formation on Mount Kirkpatrick and north Victoria Land, Ross Dependency, Antarctica. It is one of the two major dinosaur-bearing rock groups found on Antarctica to date; the other is the Snow Hill Island Formation and related formations from the Late Cretaceous of the Antarctic Peninsula. The formation has yielded some Mesozoic specimens, but most of it is as yet unexcavated. Part of the Victoria Group of the Transantarctic Mountains, it lies below the Prebble Formation and above the Falla Formation.{{cite journal |last1=Elliot |first1=D.H. |title=The Hanson Formation: a new stratigraphical unit in the Transantarctic Mountains, Antarctica. |journal=Antarctic Science |date=1996 |volume=8 |issue=4 |pages=389–394 |doi=10.1017/S0954102096000569 |bibcode=1996AntSc...8..389E |s2cid=129124111 |url=https://www.cambridge.org/core/journals/antarctic-science/article/abs/hanson-formation-a-new-stratigraphical-unit-in-the-transantarctic-mountains-antarctica/D0AB7670F2843E9A1E85947558689CC7 |access-date=15 November 2021|url-access=subscription }} The formation includes material from volcanic activity linked to the Karoo-Ferar eruptions of the Lower Jurassic.{{cite journal |last1=Ross |first1=P.S. |last2=White |first2=J.D.L. |title=Debris jets in continental phreatomagmatic volcanoes: a field study of their subterranean deposits in the Coombs Hills vent complex, Antarctica |journal=Journal of Volcanology and Geothermal Research |date=2006 |volume=149 |issue=1 |pages=62–84 |doi=10.1016/j.jvolgeores.2005.06.007 |bibcode=2006JVGR..149...62R |url=https://www.researchgate.net/publication/223902754}}{{cite journal |last1=Elliot |first1=D. H. |last2=Larsen |first2=D. |title=Mesozoic volcanism in the Transantarctic Mountains: depositional environment and tectonic setting |journal=Gondwana 8—Assembly, Evolution, and Dispersal |date=1993 |volume=1 |issue=1 |pages=379–410}} The climate of the zone was similar to that of modern southern Chile, humid, with a temperature interval of 17–18 degrees.{{cite journal |last1=Chandler |first1=M. A. |last2=Rind |first2=D. |last3=Ruedy |first3=R. |title=Pangaean climate during the Early Jurassic: GCM simulations and the sedimentary record of paleoclimate |journal=Geological Society of America Bulletin |date=1992 |volume=104 |issue=1 |pages=543–559 |doi=10.1130/0016-7606(1992)104<0543:PCDTEJ>2.3.CO;2 |bibcode=1992GSAB..104..543C |url=https://pubs.giss.nasa.gov/abs/ch07200r.html|url-access=subscription }}
The Hanson Formation is correlated with the Section Peak Formation of the Eisenhower Range and Deep Freeze Range, as well as volcanic deposits on the Convoy Range and Ricker Hills of southern Victoria Land. Recent work has successfully correlated the Upper Section Peak Formation, as well unnamed deposits in Convoy Range and Ricker Hills with the Lower Hanson, all likely of Sinemurian age and connected by layers of silicic ash, while the upper section has been found to be Pliensbachian, and correlated with a greater volcanic pulse, marked by massive ash inputs.
History
File:Mount Kirkpatrick dinosaur site.jpg, with stratigraphic context of the Hanson Formation]]
The Victoria Group (also called Beacon Supergroup) from the Central Transantarctic Mountains was defined by Ferrar in 1907, when he described the "Beacon Sandstone" of the sedimentary rocks in the valleys of the Victoria Land.{{cite journal |last1=Ferrar |first1=H.T. |title=Report on the field geology of the region explored during the 'Discovery' Antarctic Expedition 1901-1904 |journal=National Antarctic Expedition, Natural History |date=1907 |volume=1 |issue=1 |pages=1–100}} Following this initial work, the term "Beacon System" was introduced for a series of similar sandstones and associated deposits that were recovered locally.{{cite journal |last1=Harrington |first1=H.J. |title=Nomenclature of rock units in the Ross Sea region, Antarctica |journal=Nature |date=1958 |volume=182 |issue=1 |page=290 |doi=10.1038/182290a0 |bibcode=1958Natur.182..290H |s2cid=4249714 |doi-access=free}} Later the "Beacon Sandstone Group" was assigned to those units in Victoria Land, with Harrington in 1965 proposing the name for different units that appear in the Beacon rocks of south Victoria Land, the beds below the Maya erosion surface, the Taylor Group and the Gondwana sequence, including the Victoria Group.{{cite journal |last1=Harrington |first1=H.J. |title=Geology and morphology of Antarctica |journal=Ivan Oye, P. & van Mieohem, J, Eds. Biogeography and Ecology of Antarctica. Monographiae Biologicae |date=1965 |volume=15 |issue=1 |pages=1–71}} This work left out several older units, such as the Permian coal measures and glacial deposits. It was not until 1963 that there was an establishment of the Gondwana sequence: the term Falla Formation was chosen to delimit a 2300 ft (700 m) series of lower quartz sandstone, a middle mica-carbon sandstone and an upper sandstone-shale unit.{{cite journal |last1=Grindley |first1=G.W. |title=The geology of the Queen Alexandra Range, Beardmore Glacier, Ross Dependency, Antarctica; with notes on the correlation of Gondwana sequences |journal=New Zealand Journal of Geology and Geophysics |date=1963 |volume=6 |issue=1–2 |pages=307–347|doi=10.1080/00288306.1963.10422067 |doi-access=free|bibcode=1963NZJGG...6..307G }} The formation lying above the Falla Formation and below the Prebble Formation was then termed the Upper Falla Formation, with considerable uncertainty about its age (it was calculated from the presence of Glossopteris-bearing beds (Early Permian) and the assumed possibility that the rocks were older than Dicroidium-bearing beds, thought to be Late Triassic, in the Dominion Range).{{cite journal |last1=Barret |first1=P.J. |title=Stratigraphy and petrology of the mainly fluviatile Permian and Triassic Beacon rocks, Beardmore Glacier area, Antarctica |journal=Institute of Polar Studies, Ohio State University |date=1969 |volume=34 |issue=2–3 |pages=132}} Later works tried to set it between the Late Triassic (Carnian) and the Lower-Middle Jurassic (Toarcian–Aalenian).{{cite journal |last1=Collinston |first1=J.W. |last2=Isbell |first2=J.L. |last3=Elliot |first3=D.H. |last4=Miller |first4=M.F. |last5=Miller |first5=J.W.G. |title=Permian-TriassicTransantarctic basin |journal=Memoir of the Geological Society of America |date=1994 |volume=184 |issue=1 |pages=173–222 |doi=10.1130/MEM184-p173 |url=https://pubs.geoscienceworld.org/gsa/books/book/191/chapter/3793607/Permian-Triassic-Transantarctic-basin |access-date=13 February 2022|url-access=subscription }}
The local Jurassic sandstones were included in the Victoria Group, with the Beacon unit defined as a supergroup in 1972, comprising beds overlying the pre-Devonian Kukri erosion surface to the Prebble Formation in the central Transantarctic Mountains and the Mawson Formation (and its unit, then separated, the Carapace Sandstone) in southern Victoria Land.{{cite journal |last1=Barret |first1=P.J. |last2=Elliot |first2=D.H. |title=The early Mesozoic volcaniclastic Prebble Formation, Beardmore Glacier area |journal=In ADIE, R.J., Ed.Antarctic Geology and Geophysics |date=1972 |pages=403–409}} The Mawson Formation, identified at the beginning as indeterminate tillite, was later placed in the Ferrar Group.{{cite journal |last1=Ballance |first1=P.F. |last2=Watters |first2=W.A. |title=The Mawson Diamictite and the Carapace Sandstone, formations of the Ferrar Group at Allan Hills and Carapace Nunatak, Victoria Land, Antarctica |journal=New Zealand Journal of Geology and Geophysics |date=1971 |volume=14 |issue=1 |pages=512–527 |doi=10.1080/00288306.1971.10421945 |doi-access=free |bibcode=1971NZJGG..14..512B }}
Extensive fieldwork later demonstrated the need for revisions to the post-Permian stratigraphy.{{cite journal |last1=Barret |first1=P.J. |last2=Elliot |first2=D.H. |last3=Lindsay |first3=J.F. |title=The Beacon Supergroup (Devonian-Triassic) and Ferrar Group (Jurassic) in the Beardmore Glacier area, Antarctica |journal=Antarctic Research Series |date=1986 |volume=36 |issue=1 |pages=339–428 |doi=10.1029/AR036p0339}} It was found that only 282 m of the upper 500 m of the Falla Formation as delimited in 1963 correspond to the sandstone/shale sequence, with the other 200 m comprising a volcaniclastic sequence. New units were then described from this location: the Fremouw Formation and Prebble Formation, the latter term being introduced for a laharic unit, not seen in 1963, that occurs between the Falla Formation and the Kirkpatrick Basalt.{{cite journal |last1=Barret |first1=P.J. |last2=Elliot |first2=D.H. |title=Reconnaissance Geologic Map of the Buckley Island Quadrangle, Transantarctic Mountains, Antarctica |journal=US Geological Survey, Antarctica |date=1973 |volume=1 |issue=1 |pages=1–42 |url=https://pubs.er.usgs.gov/publication/a3 |access-date=15 November 2021}} A complete record was recovered at Mount Falla, revealing the sequence of events in the Transantarctic Mountains spanning the interval between the Upper Triassic Dicroidium-bearing beds and the Middle Jurassic tholeiitic lavas. The upper part of the Falla Formation contains recognizable primary pyroclastic deposits, exemplified by resistant, laterally continuous silicic tuff beds, that led this to be considered a different formation, especially as it shows erosion associated with tectonic activity that preceded or accompanied the silicic volcanism and marked the onset of the development of a volcano-tectonic rift system.
The Shafer Peak Formation was named from genetically identical deposits from north Victoria Land (exposed on Mt. Carson) in 2007 and correlated with the Hanson Formation, defined as tuffaceous deposits with silicic glass shards along with quartz and feldspar.{{cite journal |last1=Schöner |first1=R. |last2=Viereck-Goette |first2=L. |last3=Schneider |first3=J. |last4=Bomfleur |first4=B. |title=Triassic-Jurassic sediments and multiple volcanic events in North Victoria Land, Antarctica: A revised stratigraphic model |journal=In Antarctica: A Keystone in a Changing World–Online Proceedings of the 10th ISAES, Edited by AK Cooper and CR Raymond et Al., USGS Open-File Report |series=Open-File Report |date=2007 |volume=1047 |issue=1 |pages=1–5 |doi=10.3133/ofr20071047SRP102}} Later works, however, have equated it to a continuation of the Hanson Formation, as part of the upper member.{{cite journal |last1=Bomfleur |first1=B. |last2=Mörs |first2=T. |last3=Unverfärth |first3=J. |last4=Liu |first4=F. |last5=Läufer |first5=A. |last6=Castillo |first6=P. |last7=Crispini |first7=L. |title=Uncharted Permian to Jurassic continental deposits in the far north of Victoria Land, East Antarctica |journal=Journal of the Geological Society |date=2021 |volume=178 |issue=1 |doi=10.1144/jgs2020-062 |bibcode=2021JGSoc.178...62B |hdl=11567/1020776 |s2cid=226380284 |url=https://pubs.geoscienceworld.org/jgs/article-abstract/178/1/jgs2020-062/590876/Uncharted-Permian-to-Jurassic-continental-deposits?redirectedFrom=fulltext |access-date=15 November 2021 |hdl-access=free}}
The name "Hanson Formation" was proposed for the volcaniclastic sequence that was described in Barrett's 1969 Falla Formation essay. The name was taken from the Hanson Spur, which lies immediately to the west of Mount Falla and is developed on the resistant tuff unit described below.
Paleoenvironment
File:Fire storm.jpg in the background]]
The Hanson Formation accumulated in a rift environment located between c. 60 and 70S, fringing the East Antarctic Craton behind the active Panthalassan margin of southern Gondwana, being dominated by two types of facies: coarse- to medium-grained sandstone and tuffaceous rocks & minerals on the fluvial strata, which suggest the deposits where influenced by a large period of silicic volcanism, maybe more than 10 million years based on the thickness.{{cite journal |last1=Elliot|first1=D. H. |last2=Larsen |first2=D. |last3=Fanning |first3=C. M. |last4=Fleming |first4=T. H. |last5=Vervoort |first5=J. D. |title=The Lower Jurassic Hanson Formation of the Transantarctic Mountains: implications for the Antarctic sector of the Gondwana plate margin |journal=Geological Magazine |date=2017 |volume=154 |issue=4 |pages=777–803 |doi=10.1017/S0016756816000388 |bibcode=2017GeoM..154..777E |s2cid=132900754 |url=https://www.cambridge.org/core/services/aop-cambridge-core/content/view/0ED8AE6AEF7D7888C2AE577F641663C0/S0016756816000388a.pdf/the-lower-jurassic-hanson-formation-of-the-transantarctic-mountains-implications-for-the-antarctic-sector-of-the-gondwana-plate-margin.pdf |access-date=7 March 2022}} When looking at the composition of this tuffs, fine grain sizes, along others aspects such as bubble-wall and tricuspate shard form or crystal-poor nature trends to suggest this volcanic events developed as distal Plinian Eruptions (extremely explosive eruptions), with some concrete layers with mineral grains of bigger size showing that some sectors where more proximal to volcanic sources. The distribution of some tuffs with accretionary lapilli, found scattered geographically and stratigraphically suggest transport by ephemeral river streams, as seen in the Oruanui Formation of New Zealand. The sandstones where likely derived of low-sinuosity sandybraided stream deposits, having interbeds with multistory cross-bedded sandstone bodies, indicators of either side channels or crude splay deposits and concrete well-stratified sections representing overbank deposits and/or ash recycled by ephemeral streams or aeolian processes. Towards the upper layers of the formation the influence of the Tuff in the sandstones get more notorious, evidenced by bigger proportions of volcanic minerals and ash-related materials embedded in between this layers. Overall, the unit deposition bear similarities to the several-hundredmetres-thick High Plains Cenozoic sequence of eastern Wyoming, Nebraska and South Dakota, with the fine-grained ash derived from distal volcanoes.
The Shafer Peak section flora is the typical reported in warm climates. Compared with the underlying Triassic layers, warm and overall humid, possibly more strongly seasonal, specially notorious by the abundance of Cheirolepidiaceae pollen, a key thermophilic element. Yet the dominance of this pollen doesn't indicate proper dry conditions, as for example mudcrack and other indicators of strong dry seasons are mostly absent, while common presence of the invertebrate ichnogenus Planolites indicates the local fluvial, alluvial or lacustrine waters where likely continuous all year, as well the presence of abundant Otozamites trends to suggest high humidity. Overall points to frost-free setting with strong seasonality in day-length given the high latitude, perhaps similar to warm-temperate, frost-free forest and open woodland as in North Island of New Zealand. Despite the proper conditions, peat accumulation was rare, mostly due to the influence of local volcanism, with common wildfire activity as show charred coalified plant remains. At Mount Carson associations of sphenophyte rhizomes and aerial stems, as well isoetalean leaves suggest the presence of overbank deposits that were developed in ephemeral pools that lasted enough to be colonized by semiaquatic plants.
Tectonically, based on the changes seen in the sandstone composition and the appearance of volcanic strata indicates the end of the so-called foreland depositional section in the Transantarctic Mountains, while appearance of arkoses with angular detritus and common Garnet points to local Palaeozoic basement uplift. The Rift Valley deposition is recovered in several coeval and underlying points, with its thickness as indicator of palaeotopographical confinement of palaeoflows coming generally to the NW quadrant, creating a setting that received both sediment derived from the surrounding rift shoulders and ash from distal eruptions.{{cite journal |last1=Elliot |first1=D. H. |title=Stratigraphy of Jurassic pyroclastic rocks in the Transantarctic Mountains |journal=Journal of African Earth Sciences |date=2000 |volume=31 |issue=1 |pages=77–89 |doi=10.1016/S0899-5362(00)00074-9 |bibcode=2000JAfES..31...77E |url=https://www.sciencedirect.com/science/article/pii/S0899536200000749 |access-date=7 March 2022|url-access=subscription }} The Main fault indicator of this rift has been allocated around the Marsh Glacier, with the so-called Marsh Fault that breaks apart Precambrian rocks and the Miller Range, with other faults including a W-facing monocline that lies parallel and east of the Marsh Fault, a NW–SE-striking small graben in the southern Marshall Mountains, the fault at the Moore Mountains, the undescribed monocline facing east in the Dominion Range and an uplifted isolated fault in the west of Coalsack Bluff. Marsh Fault was likely active during the early Jurassic, leading to a development of an extensive rift valley system several thousand kilometres long along which basaltic magmatism was focused later towards the Pliensbachian, when the Hanson Formation deposited, somehow similar to East African Rift Valleys and specially Waimangu Volcanic Rift Valley, with segmentation in the rift and possible latter reverse faulting.
.
Fungi
{{Paleobiota-key-compact}}
Paleofauna
The first dinosaur to be discovered from the Hanson Formation was the predator Cryolophosaurus, in 1991; it was formally described in 1994. Alongside these dinosaur remains were fossilized trees, suggesting that plant matter had once grown on Antarctica's surface before it drifted southward. Other finds from the formation include tritylodonts, herbivorous mammal-like reptiles and crow-sized pterosaurs. Surprising was the discovery of prosauropod remains, which were found commonly on other continents only until the Early Jurassic. However, the bone fragments found in the Hanson Formation were dated to the Middle Jurassic, millions of years later. In 2004, paleontologists discovered partial remains of a large sauropod dinosaur that has not yet been formally described.
= Synapsida =
= Pterosauria =
= Dinosaurs =
== Ornithischia ==
==Sauropodomorpha==
==Theropoda==
=Arthropoda=
At southwest Gair Mesa the basal layers represent a lake shore and are characterised by the noteworthy preservation of some arthropod remains.
| class="wikitable sortable" |
| Taxon
! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |
|---|
| Blattodea
| Indeterminate |
| Middle Hanson Formation | Complete specimen | Indeterminate Cockroach material | |
| Coleoptera
| Indeterminate (various) |
| Lower Hanson Formation | Isolated elytron | Indeterminate beetle remains | |
| Conchostraca
| Indeterminate (various) |
|Lower and Middle Hanson Formation | Isolated valves | Numerous conchostracan remains, found associated with lagoonar deposits and major indicators of water bodies locally along Scoyenia burrows | |
| style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| D. isp. |style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| Lower Hanson Formation |style="background:#FEF6E4;"| Trace fossils |style="background:#FEF6E4;"| Trace fossils in lacustrine environment, probably made by arthropods (arachnids or myriapods) |style="background:#FEF6E4;"| |
| Euestheria
|
|
| Lower and Middle Hanson Formation | Isolated valves | A clam shrimp (“conchostracan”), member of the family Lioestheriinae. | |
| Lioestheria
|
|
| Lower and Middle Hanson Formation | Isolated valves | A clam shrimp (“conchostracan”), member of the family Lioestheriinae. | |
| Ostracoda
| Indeterminate (various) |
| Middle Hanson Formation | Isolated valves | Numerous ostracodan remains, found associated with lagoonar deposits and indicators of water bodies locally along Scoyenia burrows and conchostracans | |
| Palaeolimnadia{{cite journal |last1=Tasch |first1=P. |title=Biostratigraphy and palaeontology of some conchostracan-bearing beds in southern Africa |journal=Palaeontologia Africana |date=1984 |volume=25 |issue=1 |pages=61–85 |url=https://pubs.geoscienceworld.org/gsa/books/book/176/chapter/3792882/FOSSIL-CONCHOSTRACA-OF-THE-SOUTHERN-HEMISPHERE-AND |access-date=8 March 2022}}
|
|
| Lower and Middle Hanson Formation | Isolated valves | A clam shrimp (“conchostracan”), member of the family Limnadiidae. | |
| style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| P. isp. |style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| Lower Hanson Formation |style="background:#FEF6E4;"| Burrows |style="background:#FEF6E4;"| Burrow fossils in lacustrine environment, probably made by arthropods. Common Planolites burrows on bedding planes document high water tables locally, as well humid atmospheric conditions |style="background:#FEF6E4;"| |
| style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| S. isp. |style="background:#FEF6E4;"|
|style="background:#FEF6E4;"| Lower Hanson Formation |style="background:#FEF6E4;"| Burrows |style="background:#FEF6E4;"| Burrow fossils in lacustrine environment, probably made by arthropods |style="background:#FEF6E4;"| |
Flora
Fossilized wood is also present in the Hanson Formation, near the stratigraphic level of the tritylodont locality. It has affinities with the Araucariaceae and similar kinds of conifers.{{cite journal |last1=Gair |first1=H. S. |last2=Norris |first2=G. |last3=Ricker |first3=J. |title=Early mesozoic microfloras from Antarctica |journal=New Zealand Journal of Geology and Geophysics |date=1965 |volume=8 |issue=2 |pages=231–235 |doi=10.1080/00288306.1965.10428109 |doi-access=free|bibcode=1965NZJGG...8..231G }} In the north Victoria Land region, plant remains occur at the base of the lacustrine beds directly underlying the initial pillow lavas at the top of the sedimentary profile. Some of the layers of Shafer Peak include remains of an in situ stand gymnosperm trees:
- At Mount Carson, at least four large tree trunks were found on an exposed bedding plane. The wood is coalified and only partially silicified, with the largest stem reaching a diameter of nearly 50 cm.{{cite journal |last1=Bomfleur |first1=B. |last2=Schneider |first2=J. W. |last3=Schöner |first3=R. |last4=Viereck-Götte |first4=L. |last5=Kerp |first5=H. |title=Fossil sites in the continental Victoria and Ferrar groups (Triassic-Jurassic) of north Victoria Land, Antarctica |journal=Polarforschung |date=2011 |volume=80 |issue=2 |pages=88–99 |url=https://www.researchgate.net/publication/234143783 |access-date=15 November 2021}}
- In Suture Bench, silicified tree trunks are found buried in situ along lava flows. Some specimens have several holes or tunnels less than 1 cm wide that may represent arthropod borings.
=Palynology=
Likely that (at least parts of) the palynomorph contents of these samples may derive from accessory clasts of underlying host strata that were incorporated and reworked during hydrovolcanic activity{{cite journal |last1=Bomfleur |first1=B. |last2=Schöner |first2=R. |last3=Schneider |first3=J. W. |last4=Viereck |first4=L. |last5=Kerp |first5=H. |last6=McKellar |first6=J. L. |title=From the Transantarctic Basin to the Ferrar Large Igneous Province—new palynostratigraphic age constraints for Triassic–Jurassic sedimentation and magmatism in East Antarctica |journal=Review of Palaeobotany and Palynology |date=2014 |volume=207 |issue=1 |pages=18–37 |doi=10.1016/j.revpalbo.2014.04.002 |bibcode=2014RPaPa.207...18B |url=https://www.sciencedirect.com/science/article/pii/S0034666714000529 |access-date=20 February 2022|url-access=subscription }}
| class="wikitable sortable" |
| Genus
! Species ! Location ! Stratigraphic position ! Material ! Notes |
|---|
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the families Caytoniaceae, Corystospermaceae, Peltaspermaceae, Umkomasiaceae and Voltziaceae |
| style="background:#D1FFCF;" |
Aratrisporites{{cite journal |last1=Musumeci|first1=G. |last2=Pertusati |first2=P. C. |last3=Ribecai |first3=C. |last4=Meccheri |first4=M. |title=Early Jurassic fossiliferous black shales in the Exposure Hill Formation, Ferrar Group of northern Victoria Land, Antarctica |journal=Terra Antartica Reports |date=2006 |volume=12 |issue=1 |pages=91–98 |url=https://www.researchgate.net/publication/286878347 |access-date=17 November 2021}} |style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with Pleuromeiales. The Plueromeiales were tall lycophytes (2 to 6 m) common in the Triassic. These spores probably reflect a relict genus. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Araucariaceae. By the Pliensbachian, Cheirolepidiaceae reduce their abundance, with coeval proliferation of the Araucariaceae-type pollen |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Osmundaceae. Near fluvial current ferns, related to the modern Osmunda regalis. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Calamitaceae. Horsetails, herbaceous flora characteristic of humid environments and tolerant of flooding. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Cheirolepidiaceae. Most samples yield well-preserved pollen and spore assemblages strongly dominated (82% and 85%, respectively, for the two species) by Classopollis grains. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Cheirolepidiaceae. The dominance of Corollina species is the defining feature of the Corollina torosa abundance zone. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Cyatheaceae or Adiantaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Cibotiaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Sphagnaceae. Sphagnum-type swamp mosses. Aquatic in temperate freshwater swamps. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Selaginellaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Schizaeaceae, Dicksoniaceae or Matoniaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Selaginellaceae. |
| style="background:#D1FFCF;" |
Nevesisporites{{cite journal |last1=Unverfärth |first1=J. |last2=Mörs |first2=T. |last3=Bomfleur |first3=B. |title=Palynological evidence supporting widespread synchronicity of Early Jurassic silicic volcanism throughout the Transantarctic Basin |journal=Antarctic Science |date=2020 |volume=32 |issue=5 |pages=396–397 |doi=10.1017/S0954102020000346 |bibcode=2020AntSc..32..396U |s2cid=224858807 |doi-access=free}} |style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with Bryophyta. Younger index taxa (e.g., N. vallatus) are mostly absent and the proportion of Classopollis is still very high. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Cupressaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the families Caytoniaceae, Corystospermaceae, Podocarpaceae and Voltziaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Podocarpaceae. Occasional bryophyte and lycophyte spores are found along with consistent occurrences of Podosporites variabilis. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Notothyladaceae. Hornwort spores. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Uncertain peridophyte affinities |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Lycopodiaceae. Absent in some samples. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Uncertain peridophyte affinities |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the family Osmundaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Sphagnaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Affinities with the Sphagnaceae. |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Uncertain peridophyte affinities |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Uncertain peridophyte affinities |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Spores |style="background:#D1FFCF;" | Uncertain peridophyte affinities |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Lower Hanson Formation |style="background:#D1FFCF;" | Pollen |style="background:#D1FFCF;" | Affinities with the family Caytoniaceae. |
=Macroflora=
| class="wikitable sortable" |
| Genus
! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |
|---|
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Cuticles |style="background:#D1FFCF;" | A member of the Pinales of the family Cheirolepidiaceae or Araucariaceae. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | C. oblonga |style="background:#D1FFCF;" | Carapace Nunantak (reworked) Shafer Peak |style="background:#D1FFCF;" | Middle Hanson Formation |style="background:#D1FFCF;" | Leaves and stems |style="background:#D1FFCF;" | A Polypodiopsidan of the family Osmundaceae. Reworked from the Hanson Formation to the Mawson Formation; represents fern leaves common in humid environments. |style="background:#D1FFCF;" | File:Cladophlebis asiatica IMG 5157 Beijing Museum of Natural History.jpg specimen]] |
| style="background:#D1FFCF;" |
Clathropteris{{cite journal |last1=Bomfleur |first1=B. |last2=Kerp |first2=H. |title=The first record of the dipterid fern leaf Clathropteris Brongniart from Antarctica and its relation to Polyphacelus stormensis Yao, Taylor et Taylor nov. emend |journal=Review of Palaeobotany and Palynology |date=2010 |volume=160 |issue=3–4 |pages=143–153 |doi=10.1016/j.revpalbo.2010.02.003 |bibcode=2010RPaPa.160..143B |url=https://www.sciencedirect.com/science/article/pii/S0034666710000370 |access-date=15 November 2021|url-access=subscription }} |style="background:#D1FFCF;" | C. meniscoides |style="background:#D1FFCF;" | Shafer Peak Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Leaf segments |style="background:#D1FFCF;" | A Polypodiopsidan of the family Dipteridaceae. It was the first record of the genus and species from the Antarctica. Specimens from Shafer Peak occur in a tuffitic mass-flow deposit and are associated with abundant charred wood indicating wildfires. |style="background:#D1FFCF;" | File:Clathropteris meniscioides.JPG specimen]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |C. murrayana C. hymenophylloides |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Pinna fragments |style="background:#D1FFCF;" | A Polypodiopsidan of the family Polypodiales. Common cosmopolitan Mesozoic fern genus. Recent research has reinterpreted it a stem group of the Polypodiales (Closely related with the extant genera Dennstaedtia, Lindsaea, and Odontosoria).{{Cite journal |last1=Li |first1=Chunxiang |last2=Miao |first2=Xinyuan |last3=Zhang |first3=Li-Bing |last4=Ma |first4=Junye |last5=Hao |first5=Jiasheng |date=January 2020 |title=Re-evaluation of the systematic position of the Jurassic–Early Cretaceous fern genus Coniopteris |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667118303033%7C |journal=Cretaceous Research |language=en |volume=105 |pages=104–136 |doi=10.1016/j.cretres.2019.04.007 |bibcode=2020CrRes.10504136L |s2cid=146355798|url-access=subscription }} |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Trapeziform fragment of a scale leaf |style="background:#D1FFCF;" | A cycadophyte of the family Bennettitales. The Specimen was found pecimen associated with Otozamites spp. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | D. sp. |style="background:#D1FFCF;" | Shafer Peak |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | One cuticle fragment on slide |style="background:#D1FFCF;" | A Pteridosperm/Seed Fern of the family Corystospermaceae. Dicroidium plants only gradually began to disappear and lingered on in Jurassic floras as minor relictual elements in more modern vegetation communities dominated by conifers, Bennettitales, and various ferns. |style="background:#D1FFCF;" | File:Dicroidium zuberi leaf.jpg specimen]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Fragments of rhizomes, unbranched aerial shoots, isolated leaf sheaths and nodal diaphragms |style="background:#D1FFCF;" | A sphenophyte of the family Equisetaceae. Sphenophytes are common elements of Jurassic floras of southern Gondwana. |style="background:#D1FFCF;" | File:Equisetites arenaceus 54645.jpg specimen]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Cuticles |style="background:#D1FFCF;" | A member of the family Cupressaceae. Related to specimens found in the Middle Jurassic of Hope Bay, Graham Land. Probably belong to the Conifer Austrohamia from the Lower Jurassic of Argentina and China. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
Isoetites{{cite journal |last1=Bomfleur |first1=B. |last2=Pott |first2=C. |last3=Kerp |first3=H. |title=Plant assemblages from the Shafer Peak Formation (Lower Jurassic), north Victoria Land, Transantarctic Mountains |journal=Antarctic Science |date=2011 |volume=23 |issue=2 |pages=188–208 |doi=10.1017/S0954102010000866 |bibcode=2011AntSc..23..188B |s2cid=130084588 |url=https://www.researchgate.net/publication/230040881|doi-access=free }} |style="background:#D1FFCF;" | I. abundans |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Stems |style="background:#D1FFCF;" | A lycophyte of the family Isoetaceae. Specimens resemble Australian ones of similar age. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
Marchantites{{cite journal |last1=Cantrill |first1=D. J. |last2=Hunter |first2=M. A. |title=Macrofossil floras of the Latady Basin, Antarctic Peninsula |journal=New Zealand Journal of Geology and Geophysics |date=2005 |volume=48 |issue=3 |pages=537–553 |doi=10.1080/00288306.2005.9515132 |bibcode=2005NZJGG..48..537C |s2cid=129854482 |url=https://www.researchgate.net/publication/232864298 |access-date=15 November 2021}}{{cite journal |last1=Cantrill |first1=D. J. |last2=Poole |first2=I. |date=2012 |title=The vegetation of Antarctica through geological time |url=https://www.cambridge.org/core/books/vegetation-of-antarctica-through-geological-time |journal=Cambridge University Press |volume=1 |issue=1 |pages=1–340 |doi=10.1017/CBO9781139024990 |isbn=9781139024990 |access-date=15 November 2021|url-access=subscription }} |style="background:#D1FFCF;" | M. mawsonii |style="background:#D1FFCF;" |Carapace Nunantak (reworked) |style="background:#D1FFCF;" | Middle Hanson Formation |style="background:#D1FFCF;" | Thalli |style="background:#D1FFCF;" | A liverwort of the family Marchantiales. Reworked from the Hanson Formation to the Mawson Formation, this liverwort is related to modern humid-environment genera. |style="background:#D1FFCF;" | File:Brunnenlebermoos Marchantia polymorpha.jpg, Marchantia]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | cf. M. goeppertii |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Pinna portions |style="background:#D1FFCF;" | A Polypodiopsidan of the family Matoniaceae. |style="background:#D1FFCF;" | File:EB1911 Palaeobotany - Matonidium Goepperti.jpg specimen]] |
| style="background:#D1FFCF;" |
Nothodacrium{{cite journal |last1=Andruchow-Colombo |first1=Ana |last2=Escapa |first2=Ignacio H |last3=Aagesen |first3=Lone |last4=Matsunaga |first4=Kelly K S |title=In search of lost time: tracing the fossil diversity of Podocarpaceae through the ages |journal=Botanical Journal of the Linnean Society |date=2023 |volume=27 |issue=1 |pages=315–336 |doi=10.1093/botlinnean/boad027 |url=https://academic.oup.com/botlinnean/advance-article/doi/10.1093/botlinnean/boad027/7237351 |access-date=6 August 2023|hdl=11336/227952 |hdl-access=free }} |style="background:#D1FFCF;" | N. warrenii |style="background:#D1FFCF;" |Carapace Nunantak (reworked) |style="background:#D1FFCF;" | Middle Hanson Formation |style="background:#D1FFCF;" | Leaves |style="background:#D1FFCF;" | A member of the family Voltziales. A genus with Resemblance with the extant Dacrydium that was referred to Podocarpaceae, yet a more recent work foun it to be just a convergently evolved relative of Telemachus. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |O. linearis O. sanctae-crucis |style="background:#D1FFCF;" |SW Gair Mesa Mount Carson Shafer Peak |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Pinnately compound leaves |style="background:#D1FFCF;" | A cycadophyte of the family Bennettitales. |style="background:#D1FFCF;" | File:Otozamites brevifolium.JPG specimen]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Indeterminate |style="background:#D1FFCF;" | Carapace Nunantak (reworked) Mount Carson |style="background:#D1FFCF;" | Middle Hanson Formation |style="background:#D1FFCF;" |Leaves Cuticles |style="background:#D1FFCF;" | A member of the Pinales of the family Araucariaceae. Reworked from the Hanson Formation to the Mawson Formation, representative of the presence of arboreal to arbustive flora. |style="background:#D1FFCF;" | File:Pagiophyllum rotzoanum raut.jpg specimen]] |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | P. stormensis |style="background:#D1FFCF;" |Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Leaf segments |style="background:#D1FFCF;" | A Polypodiopsidan of the family Dipteridaceae. Closely related to Clathropteris meniscoides. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Cone scales |style="background:#D1FFCF;" | A member of the Pinales of the family Pinaceae. |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" | Indeterminate |style="background:#D1FFCF;" | Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Fragment of an up to 2 mm long coiledpteridophyll crozier |style="background:#D1FFCF;" | A Fern of Uncertain relationships. Spiropteris represents fossils of Coiled fern leaves |style="background:#D1FFCF;" | |
| style="background:#D1FFCF;" |
|style="background:#D1FFCF;" |Indeterminate |style="background:#D1FFCF;" |Mount Carson |style="background:#D1FFCF;" | Lower and Middle Hanson Formation |style="background:#D1FFCF;" | Fragment of a large, pinnately compound leaf |style="background:#D1FFCF;" | A cycadophyte of the family Bennettitales. |style="background:#D1FFCF;" | File:Zamites feneonis 34.JPG specimen]] |
See also
{{Portal|Paleontology}}
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