The early Maastrichtian kossmaticeratid ammonite Gunnarites serves as an important biostratigraphic index fossil for correlating between localities within the James Ross Basin (JRB), Antarctica. The JRB is the highest southern paleolatitude marine sedimentary outcrop record of the Upper Cretaceous. Gunnarites is abundant within a relatively narrow stratigraphic interval in the JRB, and its presence in outcrops is used to recognize this specific interval, which is coeval with environmental disturbances including cooling temperatures and local sea level regression. Early taxonomic work on the genus (e.g., Spath, 1953) qualitatively described morphological differences between Gunnarites specimens from different locations within the JRB; if real, these location-based differences could have important implications for the utility of Gunnarites for biostratigraphy in the JRB and could contribute to our understanding of controls (e.g., environmental or temporal) on ammonite morphology.To test whether JRB Gunnarites specimens exhibit location-based morphological differences, we collected morphometric measurements (conch morphology and ribbing parameters) from multiple ontogenetic stages on 118 specimens from seven distinct localities within the JRB. We used linear mixed models and generalized additive mixed models to quantitatively evaluate mean differences in morphological variables by location, while accounting for variation in specimen size (i.e., characterizing scaling relationships between size and shape). Every morphological variable except whorl radius expansion rate exhibited significant location-based differences, although patterns of variation across sites differed by morphological variable. These location effects on Gunnarites morphology may be a result of phenotypic variation along an environmental gradient (e.g., depth), a result of temporal effects (e.g., evolution), or a combination of both. Large magnitude morphological differences between nearby locations may also be due, in part, to the influence of stratigraphic repetitions produced by previously hypothesized structural features in the JRB such as faults or folds, which could disrupt spatial or temporal gradients in the basin. Untangling the exact mechanisms behind location-based morphological differences in Gunnarites must await more precise, independent, age-dating of each outcrop.

Two specimens of exceptionally well-preserved Antarctic Eocene goniasterids are described. The first one, Billasterblakei gen. et sp. nov., is characterized by a dense granulation on the actinal surface with some spherical granules arranged into a rosette-like structure, enlarged antepenultimate superomarginal plates-in three out of five arms-corresponding to two inferomarginal plates, and granules and pedicellariae pits on marginal and abactinal plates. The second specimen, Buterminaster elegans, is characterized by a terminal plate-enlarged into a subtrigonal single plate covering completely the abactinal part of the arm tip-and granulation on the surface of actinal and marginal plates as well as along the periphery of actinal, abactinal, and marginals plates. Based mainly on the presence of surface granulation, Buterminaster is here considered a valid genus and not a synonym of Pentagonaster. The Eocene asteroids are associated with well-preserved bryozoans, brachiopods, a single polyplacophoran, echinoids, and serpulids, among other marine organisms inhabiting hard or firm substrates. Their exceptional preservation is attributed to rapid burial. The relatively diverse Eocene asteroid genera are quite different from modern Antarctic goniasterids but share many similarities with extant taxa outside Antarctica. Billaster shares many characteristic features with the extant genera Eknomiaster and Pawsonaster, which are restricted to New Caledonia-Kermadec and Tropical Atlantic regions (up to Uruguay), respectively, and are considered stemward genera of the Pentagonasterinae clade. Therefore, these well-preserved asteroids are significant to elucidate the origin, evolution, and dispersal of the group.

Abstract. On the Fueguian Atlantic coast and in the southern Andean fold and thrust belt, the Paleogene is partially represented by numerous turbiditic deposits. Between Río Bueno and Cabo Leticia in Península Mitre, the Paleocene–Eocene is represented by the Río Claro Group (Cabo Leticia, La Barca, Punta Noguera, and Cerro Ruperto formations) and the Río Bueno Formation; which together constitute a ∼1050-m-thick succession. Calcareous nannofossil assemblages recovered from 95 samples were analyzed to determine their relative ages. The Cabo Leticia Formation was barren in nannofossils. The upper LB2 Member of La Barca Formation contained Rhomboaster cuspis and Fasciculithus richardii, frequent in the Paleocene/Eocene boundary (subzones NP9a/NP9b). Nannofossils recovered from Punta Noguera Formation indicate an early Eocene age (biozones NP9b–NP10), with Fasciculithus tympaniformis, Rhomboaster cuspis, and abundant Toweius spp. The Cerro Ruperto Formation provided one productive sample, with specimens of Reticulofenestra spp. and Toweius spp., which indicates an early Eocene age for the formation (biozones NP12–NP13). The Río Bueno Formation yields calcareous nannofossil assemblages characterized by Chiasmolithus eograndis, Chiasmolithus expansus, Toweius spp., and Reticulofenestra spp., which indicate a late early Eocene to middle Eocene age (biozones NP14–NP15). Although the calcareous nannofossil record is discontinuous due to preservational biases in the Río Claro Group, our data allow a better age constraint for the investigated formations and to correlate these units with other surface and subsurface units in the Austral Basin. Resumen. En la costa atlántica fueguina y en la faja plegada y corrida de los Andes Fueguinos, el Paleógeno está representado parcialmente por numerosos sistemas turbidíticos. Entre el Río Bueno y el Cabo Leticia en Península Mitre, el Paleoceno–Eoceno está integrado por la Formación Río Bueno y el Grupo Río Claro (formaciones Cabo Leticia, La Barca, Punta Noguera y Cerro Ruperto) que alcanzan ∼1050 m de espesor. En este trabajo se analizan los ensambles de nanofósiles calcáreos de 95 muestras a fin de precisar sus edades relativas. La Formación Cabo Leticia resultó estéril en nanofósiles. El miembro superior de la Formación La Barca, LB2, contiene ejemplares de Rhomboaster cuspis y Fasciculithus richardii, frecuentes en el límite Paleoceno/Eoceno (subzonas NP9a–NP9b). Los nanofósiles recuperados en la Formación Punta Noguera indican una edad Eoceno temprano (biozonas NP9b–NP10), con Fasciculithus tympaniformis, Rhomboaster cuspis y abundantes Toweius spp. La Formación Cerro Ruperto proporcionó una muestra fértil, con ejemplares de Reticulofenestra spp. y Toweius spp., asignables al Eoceno temprano (biozonas NP12–NP13). La Formación Río Bueno, proveyó ensambles de nanofósiles caracterizados por Chiasmolithus eograndis, Chiasmolithus expansus Toweius spp. y Reticulofenestra spp., asignables al Eoceno temprano tardío - Eoceno medio (biozonas NP14–NP15). Aunque el registro de nanofósiles calcáreos es discontinuo debido a las facies sedimentarias del Grupo Río Claro, nuestros datos permiten una mejor restricción de la edad de las formaciones investigadas y correlacionarlas con otras unidades aflorantes y del subsuelo en la Cuenca Austral.

The new ichnotaxon Bromleyia magnifica n. igen., n. isp., attributed to the feeding activity of bivalves, is proposed. This ichnotaxon consists of clusters of closely spaced curved ridges that form a fan-shaped structure oppositely distributed on both sides of a longitudinal axis or, more rarely, being present only on one side. Intergradation between Protovirgularia, Lockeia, and Bromleyia forms a compound trace fossil that records the activity of a cleft-foot protobranch bivalve while burrowing, moving through the sediment, and stopping to deposit feed. A specimen from the Carboniferous of Arkansas, previously regarded as Lophoctenium isp., is here included in Bromleyia magnifica. The spreite in Lophoctenium reflects complex behavioural patterns of horizontal strip-mining deposit feeders, including bundles of tubes bending to one side in a pectinate way or arranged on both sides in a highly systematic fashion, which contrasts with the coarse, horizontal fan-shaped, curved bundle of ridges from the Arkansas specimen. The trace fossil Hillichnus lobosensis records the activities of tellinacean deposit feeders and displays feather-like spreite structures reminiscent of Bromleyia. However, the spreite in Hillichnus is more organized, recording repetitive probing through the sediment in horizontal, oblique, and vertical directions of the tubular inhalant siphon. The resulting complex feeding structure, recorded in multiple preservational tiers, displays an alternate arrangement of ridges on either side of an axial basal structure. This configuration differs from the mostly horizontal, less-organized, coarse bundle of ridges with broadly opposite distribution to the sides of an axis present in Bromleyia. Moreover, contrary to Hillichnus, Bromleyia is commonly associated with Lockeia, indicating significant differences in burrowing strategy and mode of construction between these two ichnotaxa.

Miocene thin-bedded turbidites from Tierra del Fuego record scarce graphoglyptids and two unusual ichnoguilds composed of diminutive elite trace fossils. The first, a monoichnospecific Cylindrichnus ichnoguild, consists of crowded, post-depositional burrows formed in surface sediments during the final phase of turbidite deposition. The second, a pre-depositional Helminthopsis ichnoguild, consists of dense aggregates of simple trails, mainly Helminthopsis and Helminthoidichnites, occupying a very shallow tier in organic-rich mud covering the sea floor prior to turbidite deposition. The trace makers of Cylindrichnus were opportunistic suspension/detritus feeding organisms, probably polychaetes, which bloomed during high flux of labile organic matter brought to internal and external levees by turbidity currents. The trace makers of Helminthopsis and Helminthoidichnites were probably nematodes that grazed on organic-rich muddy sediments with abundant disseminated pyrite associated with Kinneyia-like and other problematic wrinkle structures, suggesting sulfur-cycling chemosynthetic microbial communities originated during interturbidite phases. The rhythmical alternation of the Cylindrichnus and Helminthopsis ichnoguilds clearly differentiate the thin-bedded turbidites of the Viamonte Formation from channel-levee complexes elsewhere, stressing the point that ichnoassemblages reflect sets of environmental parameters and not necessarily particular depositional settings.

The Snow Hill Island Formation (SHIF; late Campanian - early Maastrichtian) crops out in the northeast of the Antarctic Peninsula and constitutes the basal part of the late Campanian-early Maastrichtian sedimentary succession of the James Ross Basin (NG Sequence). Its major exposures occur at the James Ross and Vega islands. Several fossil-bearing localities have been identified in the SHIF providing a valuable fauna of invertebrates and vertebrates, and flora. Our study focuses on the vertebrate fauna recovered at Gamma and Cape Lamb members of the SHIF. The marine vertebrate assemblages include chondrichthyans, actinopterygians, and marine reptiles (elasmosaurid plesiosaurs and mosasaurs). A diverse terrestrial vertebrate assemblage has been reported being characterized by dinosaurs (sauropod, elasmarian ornithopods, nodosaurid ankylosaur, and a paravian theropod), pterosaurs and birds. Most SHIF dinosaurs share close affinities with penecontemporaneous taxa from southern South America, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the Late Cretaceous. The Snow Hill Island Formation provides the most diverse Late Cretaceous marine and continental faunas from Antarctica. The present study summarizes previous and new vertebrate findings with the best actualized stratigraphical framework, providing a more complete fauna association and analyzing further perspectives.

The early Miocene marine deposits in Tierra del Fuego bear a group of struthiolariid gastropods that stand out for their high morphological variability. since the end of the 19th century this variability was interpreted as reflecting (1) a highly diversified rapidly evolving group of species or (2) a single, plastic species characterized by ample intraspecific variability. The morphological study of more than 100 specimens of the Fuegian struthiolariid genus Perissodonta Martens collected in the Carmen Silva, Viamonte, and Irigoyen formations indicate that significant parameters, such as shell shape, spire length and number of spiral and axial sculptures (cords, threads, tubercles) vary continuously within an ample range of values, favoring a single, plastic species. Topotype specimens of Perissodonta ameghinoi (Ihering), collected from the early Miocene Monte León Formation in Patagonia, show similar plasticity of characters. Furthermore, recent topotype material of Perissodonta georgiana Strebel from Islas Georgias del Sur, a species considered very close or junior synonym of the genotype species P. mirabilis (Smith), indicates a similar degree of plasticity. Accordingly, the Fuegian struthiolariids previously assigned to Perissodonta ameghinoi; P. fueguina (Ihering); or P. densestriata (Ihering) are here referred to P. ameghinoi, a struthiolariid gastropod restricted to the early Miocene in Tierra del Fuego and Patagonia.

This paper documents calcareous nannofossil assemblages and the bioevents recorded in the Austral basin of Tierra del Fuego, Argentina. Fifty samples from the type section of the Cerro Colorado Formation were analyzed. Nannoflora is moderately preserved and indicates a late Eocene to early Oligocene age for sedimentary rocks of this formation. Biostratigraphic results are based on distribution patterns of calcareous nannofossils assemblages, permitting comparison with the Southern Ocean zonations and some correlations with standard schemes. Our biostratigraphic interpretation shows an almost complete stratigraphic section spanning from the Priabonian to Rupelian Stages and calcareous nannofossil Chiasmolithus oamaruensis to Blackites spinosus zones, or the low latitude zones of Martini NP18 to NP21. The oldest fossiliferous rocks from the type locality of the Cerro Colorado Formation contain Chiasmolithus oamaruensis indicating nannofossil Zone NP18. The Eocene/Oligocene boundary was placed between the last occurrence (LO) of Reticulofenestra oamaruensis and the increasing in abundance (IB) of Reticulofenestra daviesii. Samples taken from the top of the section belong to the Estancia María Cristina Beds have Cyclicargolithus abisectus. During the late middle to late Eocene a hiatus is suggested between the Cerro Colorado and Leticia formations evident by a 39 Ma detrital zircon age dating, and the first occurrence (FO) of Dictyococcites bisectus. Furthermore, the presence of C. abisectus in the Estancia María Cristina Beds suggests an unconformity with the underlying Cerro Colorado Formation as previously inferred by stratigraphic relationships.

ABSTRACT.- In the Atlantic coast of Tierra del Fuego, Miocene, foreland Austral basin strata of the Viamonte Formation are currently interpreted as deep marine channel-levee complexes. New data on sedimentary facies, paleocurrents, and stratigraphic relationships documents, however, more complex settings. We recognize in the Viamonte Formation three higher-rank architectural elements: 1) a transverse system of gullies and other slope deposits, including gully axis, gully off-axis/gully margin, and slope-gully abandonment sub-elements; 2) an axial system, the channel belt, including channel fill, lateral accretion, internal-levee/terrace, and basal slumps sub-elements; and 3) another axial system, the external levee. Gullies in the transverse system are carved into external-levee deposits of the Viamonte Formation or older lobe deposits. Dominant sedimentary facies are mass transport deposits in the gully fill; thin-bedded turbidites in the external levee, internal levee, and terraces; and thick, high-density turbidite sandstones in the channel fill. In the transverse system, paleocurrents are directed to the NW-NE, down dip high-relief progradational clinoforms, and in the axial systems to the SE, parallel to the basin foredeep. Axial systems are located either at the base, or at subtle slope-breaks of transverse clinoforms. The envisaged depositional architectures of these axial and transverse systems offer excellent analogues for similar, poorly exposed Upper Cretaceous-Paleogene Austral basin turbidites and may help to interpret the source and routing of sand-rich deposits in the adjacent Malvinas foreland basin.

A new high-latitude record of the trace fossil Macaronichnus segregatis degiberti is documented from the lower Miocene Punta Basilica beds, Tierra del Fuego, which were previously considered to be deep-marine channel and levee deposits. Based on a combined ichnological and sedimentological study, however, these beds are herein re-interpreted as shallow-marine, delta-front clinoform deposits. Macaronichnus-bearing beds in the stratigraphically older clinoforms are characterized by: (1) sandstones with wave ripples and wave-ripple cross-lamination; (2) cross-stratified sandstones forming large compound dunes and tidal bars; and (3) intervening heterolithic mudstone-sandstone couplets with current and wave ripples. The sedimentary facies preserving M. s. degiberti were deposited during the onset of transgression, indicated by wave and tide reworking of underlying steeply dipping, delta-front clinoforms deposits. The master bedding surfaces of compound tidal bars are characterized by a dense, monospecific fabric of M. s. degiberti. Compared with other Macaronichnus ichnofabrics, reported elsewhere as characterizing short colonization windows on foresets of tidal dunes or bars, the Punta Basilica ichnofabric represents a longer colonization window, associated with episodic reworking and redeposition of loose, nutrient-rich sand grains just above the master bedding surfaces. The record of M. s. degiberti in Tierra del Fuego supports the previous interpretations that restrain its producer to high-latitude, shallow-marine cold waters.

Recent magnetostratigraphic works from different areas of the James Ross Basin have expanded on chronostratigraphic studies previously based on ammonite, palynomorph and nanoplankton biostratigraphy, and strontium isotope stratigraphy. Here we present a new magnetostratigraphy of Coniacian through Campanian marine sedimentary rocks from Hidden Lake, Santa Marta and Snow Hill Island Formations, on northwest James Ross Island. A total of 189 paleomagnetic directions were obtained along more than 1500 m of stratigraphic thickness from Brandy Bay to Santa Marta Cove areas, identifying three polarity chrons of the global polarity time scale. The local magnetostratigraphic column starts in the upper part of the Cretaceous Normal Superchron C34N (Coniacian) and ends in Chron C33N (middle Campanian). The correlation between the magnetostratigraphy and the age framework given by ammonite biostratigraphy allowed the assignment of precise ages to particular horizons of the Santa Marta Formation. The newly identified geomagnetic polarity reversals are the earliest identified in the James Ross Basin and include: a) C34N/C33R (84.2 Ma, late Santonian - early Campanian) in the Alpha Member of the Santa Marta Formation and b) C33R/C33N (79.9 Ma, middle Campanian) in the upper Beta Member (Santa Marta Formation). By integrating this new data with previous work, we present a complete Upper Cretaceous - lowermost Paleogene chronostratigraphical framework for the basin, spanning both proximal to distal sedimentary facies of the Marambio Group.

There are two contrasting opinions on the stratigraphic and palaeogeographic distribution of the relatively rare trace fossil Ophiomorpha irregulaire: 1) the trace is mostly restricted to the Upper Cretaceous of the Western Interior Seaway, or 2) it has a post-Palaeozoic record and a worldwide geographic distribution. In this study we document the finding of O. irregulaire in Upper Cretaceous turbidites of the Alta Vista Formation, southern Patagonia, providing additional evidence on the morphology and composition of its pelletal masses, the ethology of its producer and the palaeogeographical and palaeoenvironmental distribution of the trace fossil. The burrow walls are lined with dark mud and their elongate, spiky pellets are formed by a sand core that is also lined with mud. The association with typical fodinichnia, such as Halopoa, Spirophyton, and Zoophycos and the common presence of O. irregulaire in sediments with abundant plant detritus, suggest that the producer was a deposit feeder. Crosscutting relationships and occurrences at several levels within thick-bedded turbidites, suggest a relatively deep tier emplacement of the trace. The finding of the trace in the Southern Hemisphere supports its envisaged worldwide palaeogeographic distribution

The sedimentology, petrography, and U-Pb dating of two Eocene volcaniclastic horizons of the Punta Torcida and Leticia formations, Austral basin, Tierra del Fuego, Argentina are interpreted and documented. The volcaniclastic deposits, pumicite breccia and tuffaceous sandstones, are formed by glass shards, plagioclase crystals, and pumiceous and lithic andesitic fragments. Originally deposited as tephra fallout, they have been subsequently reworked and redeposited in marine settings. The final deposits, however, are interpreted essentially as syn-eruptive. U-Pb dating of detrital zircons gave a 46.3 +/- 0.4 Ma (early Lutetian) age for the top of the Punta Torcida Formation and 41.9 +/- 0.71 (late Lutetian) to 39.6 +/- 0.82 (Bartonian) ages for the Leticia Formation. Paleogene volcanic rocks are unknown in the Southern Patagonian-Fuegian Andes; hence the studied volcanic deposits with minimal reworking are important to evaluate the time lag between eruption and true depositional ages in detrital zircons. The resulting dates allow evaluating the timing of the important, basin-wide, intra-Eocene unconformity known from Tierra del Fuego to Lago Argentino, Santa Cruz, Argentina. The documented eruptive phases are related to Andean magmatism, probably located in the outcrop area of the Seno Ano Nuevo suite in the Chilean Archipelago.

We describe new material of the subfamily Gaudryceratinae in Antarctica, including five new species: Gaudryceras submurdochi Raffi and Olivero sp. nov., Anagaudryceras calabozoi Raffi and Olivero sp. nov., Anagaudryceras subcompressum Raffi and Olivero sp. nov., Anagaudryceras sanctuarium Raffi and Olivero sp. nov., and Zelandites pujatoi Raffi and Olivero sp. nov., recorded in Santonian to Maastrichtian deposits of the James Ross Basin. The early to mid-Campanian A. calabozoi Raffi and Olivero sp. nov. exhibits a clear dimorphism, expressed by marked differences in the ornament of the adult body chamber. Contrary to the scarcity of representative members of the subfamily Gaudryceratinae in the Upper Cretaceous of other localities in the Southern Hemisphere, the Antarctic record reveals high abundance and diversity of 15 species and three genera in total. This highly diversified record of gaudryceratins is only comparable with the Santonian-Maastrichtian Gaudryceratinae of Hokkaido, Japan and Sakhalin, Russia, which yields a large number of species of Anagaudryceras, Gaudryceras, and Zelandites. The reasons for a similar, highly diversified record of the Gaudryceratinae in these distant and geographically nearly antipodal regions are not clear, but we argue that they probably reflect a similar paleoecological control.

The replacement of seed-free plants and gymnosperms by flowering plants during the Cretaceous is one of the most important biotic events in the evolution of life. However, the magnitude of this global turnover remains largely unknown. Here we present sampling-standardized diversity estimates from a high resolution palynological record of the Late Cretaceous (85-66 Ma) from Antarctica, in the context of the past climatic events. Our fossil evidence reveals the occurrence of a rich Campanian flora peaking at c. 80 Ma, with angiosperms as the most diverse group of plants for the first time in Antarctica. This peak of diversity was followed by a period of a stepwise deterioration; 60% of ferns and 40% of gymnosperms became locally extinct from the early/mid-Campanian to the late Maastrichtian. Although angiosperms also faced several extinctions - 25% became extinct - they were far less affected than nonangiosperms. The onset of deterioration of the greenhouse conditions at the end of the Cretaceous - low CO2 and global cooling trends - would have led to our observed pattern of change. Overall, our study reveals the beginning of a profound floristic turnover in the highest southern latitudes that pre-dates the major extinction event of the end of the Cretaceous by 15 Myr.

Combined research on the structural and stratigraphic evolution of the southeastern Austral Basin identifies three major depositional systems strongly influenced by the tectonic stages of the Fuegian Andes between the Late Cretaceous and the Miocene. During orogenic growth, a submarine ramp system characterized by oblique progradational clinoforms with transverse sediment dispersal, formed adjacent to the deformation front in the wedge-top or proximal foredeep. In moments when the tectonic load and flexural subsidence were reduced, this system was replaced by a progradational-aggradational system with oblique to sigmoidal clinoforms. This occurred during a short span in the middle Eocene, but especially and definitively after contractional deformation ceased in the early Miocene. The third depositional system was long lived, and comprised axial turbidite channel systems located at the clinoform bases, which re-routed sediment toward the deeper foredeep of the western Malvinas Basin. Distinct facies types develop in each depositional system, and their recognition allows evaluating sediment fairways in the foreland basin system.

ABSTRACTTide-influenced deposits of the Pennsylvanian Rock Lake Shale Member, Stanton Formation, Missouri and Kansas (U.S.A.), contain well-preserved evidence of the burrowing activities of protobranch bivalves, including locomotion (Protovirgularia) and locomotion-resting (Protovirgularia-Lockeia) trace fossils. Protovirgularia shows three distinct morphotypes, the morphological variability of which was controlled by external factors such as substrate conditions, toponomy, and undertrack deficiency. Extreme morphological modifications of Protovirgularia and/or Lockeia, represented by irregular bilobate structures, probably result from erosion and subsequent partial passive filling of the original biogenic structures. In addition, very well-preserved trace fossils showing intergradation of a fan-shaped cluster of ridges with Protovirgularia-Lockeia structures are interpreted as a compound biogenic structure that represents locomotion, resting, and feeding activities of burrowing protobranch bivalves.

Two paleomagnetic poles of 80 and 75 Ma have been computed from 191 to 123 paleomagnetic samples, respectively, of the marine sedimentary units of the Upper Cretaceous Marambio Group exposed in the James Ross Island, Antarctic Peninsula. Paleomagnetic behaviors during stepwise thermal demagnetization and rock magnetic analyses indicate that magnetization is likely primary and carried by SD-PSD detrital titanomagnetite. Application of an inclination shallowing correction by the elongation-inclination method yielded a significant inclination shallowing affecting the older (ca. 80 Ma) succession exposed in the northwest area of the island. However, the paleomagnetic directions computed from the younger (ca. 75 Ma) succession outcropping in the southeast corner of the island yielded an indeterminate result using the same analysis. The inclination shallowing-corrected 80 Ma paleopole position plus previous ones of ca.110, 90 and 55 Ma were used to construct the Apparent Polar Wander Path (APWP) for the Antarctic Peninsula during the Late Cretaceous-Paleocene. This path confirms that oroclinal bending of the Antarctic Peninsula as well as relative displacement with respect to East Antarctica are negligible since 110 Ma. Comparison with the apparent polar wander path for South America for the 130-45 Ma period suggests that this continent and the Antarctic Peninsula kept a very similar relative paleogeographic position since 110 Ma until 55 Ma, which likely meant a physical link between both continental masses. During that period, both continents underwent a relatively fast southward displacement of around 7 degrees and a clockwise rotation relative to the Earth spin axis that can be bracketed between around 100 and 90 Ma. Oroclinal bending of the Fuegian Andes was likely due to tectonic interactions between the Patagonian-Fuegian Andes and the Antarctic Peninsula promoted, at least partially, by such displacements. By 55 Ma the Antarctic Peninsula probably was starting or about to start its final separation from South America.