Application of diatoms to tsunami studies.

Lisbon earthquake and tsunami in 1755 (From Wikipedia Commons)

Lisbon earthquake and tsunami in 1755 (From Wikipedia Commons)

Diatoms are unicellular algae with golden-brown photosynthetic pigments with a fossil record that extends back to Early Jurassic. The most distinctive feature of diatoms is their siliceous skeleton known as frustule that comprise two valves. They live in aquatic environments, soils, ice, attached to trees or anywhere with humidity and their remains accumulates forming diatomite, a type of soft sedimentary rock. Diatoms are the dominant marine primary producers in the oceans and play a key role in the carbon cycle and in the removal of biogenic silica from surface waters. But diatoms are also a valuable tool in reconstructing paleoenvironmental changes because of their sensitivity to environmental factors including salinity, tidal exposure, substrate, vegetation, pH, nutrient supply, and temperature found in specific coastal wetland environments. Through years, diatoms become part of the coastal sediments, resulting in buried assemblages that represent an environmental history that can span thousands of years. Diatoms alone cannot differentiate tsunami deposits from other kinds of coastal deposits, but they can provide valuable evidence for the validity of proposed tsunami deposits (Dura et al., 2015).

Electron microscope image of Diatoms from high altitude aquatic environments of Catamarca Province, Argentina (From Maidana and Seeligmann, 2006)

Electron microscope image of Diatoms from high altitude aquatic environments of Catamarca Province, Argentina (From Maidana and Seeligmann, 2006)

Tsunami deposits can be identify by finding anomalous sand deposits in low-energy environments such as coastal ponds, lakes, and marshes. Those anomalous deposits are diagnosed using several criteria such as floral (e.g. diatoms) and faunal fossils within the deposits. The delicate valves of numerous diatom species may be unusually well preserved when removed from surface deposits and rapidly buried by a tsunami.

Diatoms within the tsunami deposits are generally composed of mixed assemblages, because tsunamis inundated coastal and inland areas, eroding, transporting, and depositing brackish and freshwater taxa. Nonetheless, problems differentiating autochthonous (in situ) and allochthonous (transported) diatoms complicates reconstructions. In general, planktonic diatoms are considered allochthonous components in modern and fossil coastal wetland assemblages, while benthic taxa can be considered as autochthonous. Diatoms can also be used to estimate tsunami run-up  by mapping the landward limit of diatom taxa transported by the tsunami.

 

References:

Hemphill-Haley, E., 1996. Diatoms as an aid in identifying late Holocene tsunami deposits. The Holocene 6, 439–448.

Tina Dura, Eileen Hemphill-Haley, Yuki Sawai, Benjamin P. Horton, The application of diatoms to reconstruct the history of subduction zone earthquakes and tsunamis, Earth-Science Reviews 152 (2016) 181–197. DOI: 10.1016/j.earscirev.2015.11.017

Armstrong, H. A., Brasier, M. D., 2005. Microfossils (2nd Ed). Blackwell, Oxford.

Barron, J.A. (2003). Appearance and extinction of planktonic diatoms during the past 18 m.y. in the Pacific and Southern oceans. “Diatom Research” 18, 203-224

The geological observations of Robert Hooke.

Ammonite fossil illustrations drawn by Robert Hooke (‘Discourse on Earthquakes’ from 1703).

Ammonite fossil illustrations drawn by Robert Hooke (‘Discourse on Earthquakes’ from 1703).

At the beginning of the sixteenth century and throughout the seventeenth century a great debate about the true nature of fossils started in Italy and extended to Europe. There was two hypothesis in dispute: the first one postulated an inorganic origin for the fossils (directly formed within rocks) and the second, which contemplated an organic origin. The court doctor to the Grand Duke of Tuscany, Nicola Steno argued that the stones called Glossopetrae or “tongue stones” looked like shark teeth because they were shark teeth deposited a long time ago. In 1667, Henry Oldenburg, the secretary of the Royal Society included an abstract of ‘The head of a shark dissected’ (Canis Carchariae Dissectum Caput) by Nicolas Steno in one of the early issues of the Philosophical Transactions. Robert Hooke (1635-1703), Curator of Experiments of the Royal Society, expressed similar ideas two years before Steno. In ‘Micrographia’ (1665) he  argued that the micro-structure of petrified wood were identical to those seen in normal wood. He also described the ‘serpentine stones’ and concluded that these stones were not formed due any ‘plastic virtue’, but were due to shells of shellfish that became filled with mud or clay or petrifying water and had over time rotted away, leaving their impressions ‘both on the containing and contained substances’ (Kusukawa, 2013).

Between 1667 and 1700, Hooke delivered a series of at least 27 lectures or ‘Discourses’ to the Royal Society on the generic subject of ‘Earthquakes’, or earth-forming processes, published in his Posthumous works (1705), and accompanied by some of Hooke’s drawings that survived among the papers of Sir Hans Sloane.

Hooke's drawing of fossil bivalves, brachiopods, belemnites, shark teeth and possibly a reptilian tooth (Copyright © The Royal Society)

Hooke’s drawing of fossil bivalves, brachiopods, belemnites, shark teeth and possibly a reptilian tooth (Copyright © The Royal Society)

Hooke’s ‘wandering poles’ theory was the first dynamic explanation of continent formation in the history of science. ‘The Earth’s rotation, he proposed, caused a bulge and thus greater altitude at the equator versus a flattening at the poles. He maintained that over time, a change in the positions of the poles on the Earth surface due to a change in the moment of inertia would cause different areas of bulging and flattening with the creation of new land or sea areas’ (Drake, 2007).

By the time that he delivered his third series of ‘Discourses’ in 1687, Hooke had arrived to three remarkable conclusions. First, that fossils were the petrified remains of once living creatures (he called ‘medals of Nature’ and part of ‘Nature’s Grammar’, to be collected like coins and read like texts) and not just twists in the rock. Second, that there had been radical changes of sea level. Third, that hill-tops in England had once formed the beds of tropical oceans as indicated by the discovered of gigantic sea shells.

Hooke’s writings were intimately connected to his birthplace: the town of Freshwater near the western edge of the Isle of Wight. Throughout his Discourses he mentioned the cliffs around Freshwater Bay from which he collected fossils. Unfortunately, many of the fossils that he collected for the Royal Society, along with his portrait as Secretary of the Society, many papers and several scientific instruments and models designed by Hooke are lost, but Hooke’s ideas were transmitted by later writers, demonstrating the continuity of the development of geological thought. Arthur Percival Rossiter even nominated him in 1935 as ‘The First English Geologist’.

Reference:

E. T. Drake, The geological observations of Robert Hooke (1635-1703) on the Isle of Wight; p19-30. Geological Society, London, Special Publications 2007, v.287; doi: 10.1144/SP287.3

Sachiko Kusukawa, Drawings of fossils by Robert Hooke and Richard Waller, Notes Rec. R. Soc. 2013 67 123-138; DOI: 10.1098/rsnr.2013.0013. Published 3 April 2013

M. J. S. Rudwick, The meaning of fossils: episodes in the history of palaeontology(University of Chicago Press, 1985)

 

The First 100 Million Years of Avian History.

The basal avian Sapeornis chaoyangensis (From Wikimedia Commons)

The basal avian Sapeornis chaoyangensis (From Wikimedia Commons)

Birds originated from a theropod lineage more than 150 million years ago. By the Early Cretaceous, they diversified, evolving into a number of groups of varying anatomy and ecology. In recent years, several discovered fossils of theropods and early birds have filled the morphological, functional, and temporal gaps along the line to modern birds. Most of these fossils are from the Jehol Biota of northeastern China, dated between approximately 130.7 and 120 million years ago. The Jehol Biota is formed from two formations: the Yixian Formation, and the Jiufotang Formation, and contain the most diversified avifauna known to date. Among them was the long bony-tailed Jeholornis, only slightly more derived than Archaeopteryx, that lived with Sapeornis, Confuciusornis, and the earliest members of Enantiornithes and Ornithuromorpha. The last two groups, form the clade Ornithothoraces, characterized by a keeled sternum, elongate coracoid, narrow furcula, and reduced hand.

Ornithuromorphs, include Gansus, Patagopteryx, Yixianornis, and Apsaravis, which form a grade on the line to Ornithurae, a derived subgroup that includes modern birds and their closest fossil relatives (Brusatte et al., 2015).

The single best record of a Cretaceous neornithine is the partial skeleton of Vegavis from the latest Cretaceous (around 68–66 million years ago) of Antarctica.

Zhenyuanlong suni (photo by Junchang Lu¨ ) from the Jehol Biota.

Zhenyuanlong suni (photo by Junchang Lu) from the Jehol Biota.

Anatomical features like aspects of egg shape, ornamentation, microstructure, and porosity of living birds trace their origin to the maniraptoran theropods, such as oviraptorosaurs and troodontids. In addition, some preserving brooding postures, are known for four oviraptorosaurs, two troodontids, a dromaeosaur, and one basal bird providing clear evidence for parental care of eggs.

In birds, particularly their forebrains, are expanded relative to body size. Birds also exhibit the most advanced vertebrate visual system, with a highly developed ability to distinguish colors over a wide range of wavelengths.

Feathers were once considered to be unique avialan structures. The megalosaurus Sciurumimus, the compsognathus Sinosauropteryx, and a few other dinosaurs, document the appearance of primitive feathers. Zhenyuanlong suni, from the Yixian Formation, provides the first evidence of well-developed pennaceous feathers in a large, non-flying dromaeosaur. Evidence indicates that the earliest feathers evolved in non-flying dinosaurs, likely for display and/or thermoregulation, and later were co-opted into flight structures in the earliest birds (Brusatte et al., 2015).

The basal avian Jeholornis prima.

The basal avian Jeholornis prima.

The evolution of flight involved a series of adaptive changes at the morphological and molecular levels, like the fusion and elimination of some bones and the pneumatization of the remaining ones. Archaeopteryx lacked a bony sternum and a compensatory specialized gastral basket for anchoring large flight muscles (O’Connor et al., 2015), while Jelohornis had several derived flight-related features of modern birds like fused sacral vertebrae, an elongated coracoid with a procoracoid process, a complex sternum, a narrow furcula, and curved scapula. In Enantiornithines, their robust pygostyle appears to have been unable to support the muscles that control the flight feathers on the tail in modern birds. The increased metabolism associated with homeothermy and powered flight requires an efficient gas exchange process during pulmonary ventilation. Recent anatomical and physiological studies show that alligators, and monitor lizards exhibit respiratory systems and unidirectional breathing akin to those of birds, which indicate that unidirectional breathing is a primitive characteristic of archosaurs or an even more inclusive group with the complex air-sac system evolving later within Archosauria.

The earliest diversification of extant birds (Neornithes) occurred during the Cretaceous period and after the mass extinction event at the Cretaceous-Paleogene (K-Pg) boundary, the Neoaves, the most diverse avian clade, suffered a rapid global expansion and radiation. A genome-scale molecular phylogeny indicates that nearly all modern ordinal lineages were formed within 15 million years after the extinction, suggesting a particularly rapid period of both genetic evolution and the formation of new species. Today, with more than 10500 living species, birds are the most species-rich class of tetrapod vertebrates.

 

References:

Brusatte, S. L., O’Connor, J. K., and Jarvis, E. D. 2015. The origin and diversification of birds. Current Biology, 25, R888-R898

Padian, K., and Chiappe, L.M. (1998). The origin and early evolution of birds. Biol. Rev. 73, 1–42.

Puttick, M. N., Thomas, G. H. and Benton, M. J. (2014), HIGH RATES OF EVOLUTION PRECEDED THE ORIGIN OF BIRDS. Evolution, 68: 1497–1510. doi: 10.1111/evo.12363 A.

Xing Xu, Zhonghe Zhou, Robert Dudley, Susan Mackem, Cheng-Ming Chuong, Gregory M. Erickson, David J. Varricchio, An integrative approach to understanding bird origins, Science, Vol. 346 no. 6215, DOI: 10.1126/science.1253293.

Letters from Father Tolkien.

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John Ronald Reuel Tolkien was born on January 3, 1892, in Bloemfontein, South Africa, and died on September 2, 1973, in Bournemouth, England. He grew up in the waning days of the Victorian Era, and died along with the Swinging London. He saw the horror of the war, and the memories of his experiences as an officer in World War I were sublimated in his fiction. As he wrote in the Introduction to the second edition of The Lord of the Rings: “it seems now often forgotten that to be caught by youth in 1914 was no less hideous an experience than to be involved in 1939 and the following years. By 1918 all but one of my close friends were dead”.

He started writing stories for his children as early as 1920, when he first sent to John, the eldest son, a letter purporting to be from Father Christmas. The letters were written over a period of 20 years to entertain Tolkien’s children each Christmas. He also created the envelopes, and designed his own stamps. In the letters, Tolkien documented the adventures and misadventures of Father Christmas and his helpers. There are some similarities between the early letters and The Hobbit. Even more, Laurence and Martha Krieg in the journal Mythlore suggested that Gandalf himself may have been developed from Father Christmas.

FatherChristmasLetters_1932

Cave Drawings with Goblin Graffiti from the Father Christmas Letter of 1932.

In the letter for 1932, Father Christmas rescues the North Polar Bear from the caves and finds Goblin wall paintings. It’s a wonderful piece full of mammoths, bison, and goblin scribblings. Tolkien wrote: “must be very old, because the Goblin fighters are sitting on drasils: a very queer sort of dwarf ‘dachshund’ horse creature… I believe the Red Gnomes finished them off, somewhere about Edward the Fourth’s time.” 

It has been suggested that the painting was copied from Baldwin Brown’s The Art of the Cave Dweller: A Study of the Earliest Artistic Activities of Man. In his work, Brown emphasized that the primitive hunter must naturally have become a keen observer of nature. The first cave paintings were found in 1870 in Altimira, Spain. The Lascaux Caves, near the village of Montignac, in France, contain some of the best-known Upper Paleolithic art, estimated in 17,300 years old. During the Pleistocene and the early Holocene, most of the terrestrial megafauna became extinct. It was a deep global-scale event. Europe witnessed the extinction of several large mammalian herbivores, such as steppe bison Bison priscus, woolly mammoth Mammuthus primigenius, woolly rhinoceros Coelodonta antiquitatis and giant deer Megaloceros giganteus. The patterns exhibited by the Late Quaternary megafauna extinction (LQE) indicated a close link with the geography of human evolution and expansion.

Tolkien also anticipated some of the tenets of modern environmentalism in the imagined world of Middle-earth and the races with which it is peopled.

References:

The Father Christmas Letters. By J.R.R. Tolkien; Allen and Unwin (1976).

THE ART OF THE CAVE DWELLER: a study of the earliest Artistic Activities of Man. By G. Baldwin Brown. John Murray. 1928. pp. xix, 280. 18s.

 

 

The Chañares Formation and the origin of dinosaurs.

The Chañares Formation (© 2012 Idean)

The Chañares Formation (© 2012 Idean)

The Chañares Formation crops out in the Ischigualasto-Villa Unión Basin, formed along the western margin of South America  during the  breakup  of  Gondwana. It represents one of the most continuous continental Triassic succesions in South America. These beds were explored by Alfred Romer and Jensen (1966) in their report on the geology of the Rio Chañares and Rio Gualo region.

Located in Talampaya National Park (La Rioja Province), the Chañares Formation is characterized at its base by a sandstone–siltstone fluvial facies with distinct lower and upper levels. The lower levels are composed of light olive grey fine-grained sandstones with abundant small brown carbonate concretions. The upper levels include fine-grained sandstones and siltstones that preserve vertebrate remains (Mancuso et al., 2014).

Geological map of the Chañares–Gualo area in Talampaya National Park (From Marsicano et al., 2015)

Geological map of the Chañares–Gualo area in Talampaya National Park (From Marsicano et al., 2015)

Volcanism played an important role in the generation and preservation of the Chañares Formation’s exceptional tetrapod fossil record. The diverse and well-preserved tetrapod assemblage includes proterochampsids, pseudosuchians, ornithodirans, large dicynodonts and smaller cynodonts. Almost all dinosauromorphs are preserved in diagenetic concretions that erode out of a thick siltstone interval 15–20 m above the base of the formation, and include Lagosuchus talampayensis, Marasuchus lilloensis Lewisuchus admixtus and Pseudolagosuchus major.

Analysing the ratio of U–Pb inside the zircon crystals found in the rocks assigns the Chañares Formation to the Late Triassic, specifically the early Carnian (236–234 Ma), between 5 to 10 million years younger than previous estimate. This also suggests a similarly age for the lower Santa Maria Formation in southern Brazil, because it shares with the Chañares assemblage a variety of tetrapod genera and species unknown from anywhere else. The new results provide the basis to construct a robust framework for calibrating the timing of macro-evolutionary patterns related to the origin and early diversification of dinosaurs in Gondwana (Marsicano et al., 2015). It also suggests there was little compositional difference between the Chañares assemblage and the earliest dinosaur assemblage from the lower part of the Ischigualasto succession, where dinosauromorphs (including dinosaurs) are a minority, with synapsids still dominant. Only 15 million years later dinosaurs begin to dominate the ecosystem.

Artist’s reconstruction of the Chanares environment during the Middle Triassic. (From Mancusso et al., 2014. Art by Jorge Fernando Herrman.)

Artist’s reconstruction of the Chanares environment during the Middle Triassic. (From Mancusso et al., 2014. Art by Jorge Fernando Herrman.)

 

References:

Marsicano, C. A., Irmis, R. B., Mancuso, A. C., Mundil, R. & Chemale, F., The precise temporal calibration of dinosaur origins, Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1512541112 (2015).

Brusatte SL, et al. (2010) The origin and early radiation of dinosaurs. Earth Sci Rev 101:68100.

Mancuso AC, Gaetano LC, Leardi JM, Abdala F, Arcucci AB (2014) The ChañaresFormation: A window to a Middle Triassic tetrapod community. Lethaia 47:244265.

Romer AS, Jensen J (1966) The Chañares (Argentina) Triassic reptile fauna. II. Sketch of the geology of the Rio Chañares, Rio Gualo region. Breviora 252:1–20.

 

A palaeobotanical perspective on the Permian extinction.

 

Leaf bank of Glossopteris leaves (Adapted from Mcloughlin, 2012)

Leaf bank of Glossopteris leaves (Adapted from Mcloughlin, 2012)

The fossil record indicates that more than 95% of all species that ever lived are now extinct. Occasionally, extinction events reach a global scale with many species of all ecological types dying out in a near geological instant. These are mass extinctions. They were originally identified in the marine fossil record and have been interpreted as a result of catastrophic events or major environmental changes that occurred too rapidly for organisms to adapt. Mass extinctions are probably due to a set of different possible causes like basaltic super-eruptions, impacts of asteroids, global climate changes, or continental drift. A central question in the understanding of mass extinctions is whether the extinction was a sudden or gradual event. This question may be addressed by examining the pattern of last occurrences of fossil species in a stratigraphic section.

Jack Sepkoski and David M. Raup identified five major extinction events in Earth’s history: at the end of the Ordovician period, Late Devonian, End Permian, End Triassic and the End Cretaceous. The most recently identified mass extinction occurred during the Middle Permian, about  262 million years ago, and it was first recognised in the marine realm as a turnover among foraminifera, with fusulinaceans among the principal casualties.

Sin título

Total diversity patterns of continental diversity (solid line) and marine diversity (dotted line) at the family level. Arrows indicate the mass extinction events. (From Cascales-Miñana and Cleal 2015)

Extinction dynamics in the marine and terrestrial biotas followed different trajectories, and only the Permo-Triassic event coincided with a clear and abrupt diminution of both realms. Moreover, analysis of the paleobotanical record has suggested that plants may have suffered an additional extinction event, that is not reflected significantly in the marine realm, at the Carboniferous–Permian boundary. Evidence also suggests that  terrestrial environments suffered a single global pulse of extinction in the latest Permian, affecting both the fauna and flora (Cascales-Miñana and Cleal 2015).

During the end-Permian Event, the woody gymnosperm vegetation (cordaitaleans and glossopterids) were replaced by spore-producing plants (mainly lycophytes) before the typical Mesozoic woody vegetation evolved. The palynological record suggests that wooded terrestrial ecosystems took four to five million years to reform stable ecosystems, while spore-producing lycopsids had an important ecological role in the post-extinction interval. A key factor for plant resilience is the time-scale: if the duration of the ecological disruption did not exceed that of the viability of seeds and spores, those plant taxa have the potential to recover (Traverse, 1988).

 

References:

Borja Cascales-Miñana, José B. Diez, Philippe Gerrienne & Christopher J.Cleal (2015): A palaeobotanical perspective on the great end-Permian biotic crisis, HistoricalBiology, DOI: 10.1080/08912963.2015.1103237

Aberhan M. 2014. Mass extinctions: ecological diversity maintained. NatGeosci. 7:171–172.

Cascales-Miñana B, Cleal CJ. 2014. The plant fossil record reflects just two great extinction events. Terra Nova. 26(3):195–200.

Darwin and the flowering plant evolution in South America.

pollen

Retimonocolpites sp. (Adapted from Llorens and Loinaze, 2015)

Charles Darwin’s fascination and frustration with the evolutionary events associated with the origin and early radiation of flowering plants are legendary. In a letter to Oswald Heer, a famous Swiss botanist, and paleontologist, Darwin wrote: “the sudden appearance of so many Dicotyledons in the Upper Chalk appears to me a most perplexing phenomenon to all who believe in any form of evolution, especially to those who believe in extremely gradual evolution, to which view I know that you are strongly opposed”. Heer discussed about the early angiosperm fossil record with Darwin, in a letter dated 1 March 1875: “if we say that the Dicotyledons begin with the Upper Cretaceous, we must still concede that this section of the vegetable kingdom, which forms the bulk of modern vegetation, appears relatively late and that, in geological terms, it underwent a substantial transformation within a brief period of time.” 

Darwin’s defense of a gradualist perspective led him to suggest that prior to the Cretaceous record of flowering plants, angiosperms had slowly evolved and diversified on a remote landmass. On 22 July 1879, in a letter to Joseph Dalton Hooker, Darwin refers to the early evolution of flowering plants as an “abominable mystery”. Nearing the end of his life, he wrote to Hooker another letter about a lost fossil record in the earliest phases of angiosperm diversification:  “Nothing is more extraordinary in the history of the Vegetable Kingdom, as it seems to me, than the apparently very sudden or abrupt development of the higher plants. I have sometimes speculated whether there did not exist somewhere during long ages an extremely isolated continent, perhaps near the South Pole.”

Letter from Charles Darwin to Joseph Dalton Hooker, written 22 July 1879 (provenance: Cambridge University Library DAR 95: 485–488)

Letter from Charles Darwin to Joseph Dalton Hooker, written 22 July 1879 (provenance: Cambridge University Library DAR 95: 485–488)

While the oldest records of the different groups of angiosperms are still in discussion, the outcrops of the Baquero Group, located in Argentinean Patagonia, contain one of the richest and most diverse Early Cretaceous floras in the Southern Hemisphere. The unit comprises three formations: Anfiteatro de Tico, Bajo Tigre and Punta del Barco. The first reports of angiosperm remains for the Anfiteatro de Tico Formation were made in 1967. The dominant types are Clavatipollenites, and Retimonocolpites.

Pollen grains  could enter into the fossil record by falling directly into swamps or lakes, or being washed into them or into the rivers and seas. The ones which are not buried in reducing sediments will tend to become oxidized and be destroyed. They reflects the ecology of their parent plants and their habitats and provide a continuous record of their evolutionary history. Gymnosperms pollen often is saccate (grains with two or three air sacs attached to the central body), while Angiosperm pollen shows more variation and covers a multitude of combinations of features: they could be  in groups of four (tetrads),  in pairs (dyads),  or single (monads). The individual grains can be inaperturate, or have one or more pores, or slit-like apertures or colpi (monocolpate, tricolpate).

pollen

Clavatipollenites sp. SEM (Adapted from Archangelsky 2013)

Clavatipollenites pollen grains are interpreted as related to the modern family Chloranthaceae. The genus was established by Couper for dispersed monosulcate pollen grains recovered from the Early Cretaceous of Britain. Currently, the genus has a very broad definition. The genus Retimonocolpites include elongated to subcircular semitectate, columellate and microreticulate pollen grains with well defined monocolpate aperture (Llorens and Loinaze, 2015). The new species Jusinghipollisticoensis sp. nov. represents one of the oldest records of trichotomosulcate, and extends the geographical distribution of Early Cretaceous trichotomosulcate pollen grains to southern South America.

The data also indicates strong similarities between the Baquero Group assemblages and other coeval units from Argentina, Australia and United States.

References:

M. Llorens, V.S. Perez Loinaze, Late Aptian angiosperm pollen grains from Patagonia: Earliest steps in flowering plant evolution at middle latitudes in southern South America, Cretaceous Research 57 (2016) 66-78

Archangelsky, S.,et al. (2009). Early angiosperm diversification: evidence from southern South America. Cretaceous Research, 30, 1073-1082.

Doyle, J. A., & Endress, P. K. (2014). Integrating Early Cretaceous fossils into the phylogeny of living Angiosperms: ANITA. Lines and relatives of Chloranthaceae. International Journal of Plant Sciences, 175, 555-560.

HALLOWEEN SPECIAL III: Lovecraft, The Tunguska Event and The Colour Out of Space.

Tunguska forest (Photograph taken by Evgeny Krinov near the Hushmo river, 1929).

Tunguska forest (Photograph taken by Evgeny Krinov near the Hushmo river, 1929).

“And by night all Arkham had heard of the great rock that fell out of the sky and bedded itself in the ground beside the well at the Nahum Gardner place.”

“The Colour Out of Space” is a short story written by  H. P. Lovecraft in 1927.  The story is set in the fictional town of Arkham, Massachusetts, where an unnamed narrator investigates a local area known as the “blasted heath”. Ammi Pierce, a local man, relates him the tragic story of a man named Nahum Gardner and how his life crumbled when a great rock fell out of the sky onto his farm. Within the meteorite there was a coloured globule impossible to describe that infected Gardner’s family, and spread across the property, killing all living things. It’s the first of Lovecraft’s major tales that combines horror and science fiction. The key question of the story of course is the meteorite. Although “the coloured globule” inside the meteorite has mutagenic properties we cannot define their nature. But as Lovecraft stated once, the things we fear most are those that we are unable to picture.

H.P. Lovecraft’s love for astronomy is well known. As an amateur astronomer, Lovecraft attended several lectures from leading astronomers and physicists of his time. In 1906 he wrote a letter to the Scientific American on the subject of  finding planets in the solar system beyond Neptune. Around this time he began to write two astronomy columns for the Pawtuket Valley Gleaner and the Providence Tribune. He also wrote a treatise, A Brief Course in Astronomy – Descriptive, Practical, and Observational; for Beginners and General Readers. In several of his astronomical articles he describes meteors as  “the only celestial bodies which may be actually touched by human hands”.

e98c4-lovecraftscientificamerican2

“The Colour Out of Space” was published nineteen year after the Tunguska Event. On the morning of June 30, 1908, eyewitnesses reported a large fireball crossing the sky above Tunguska in Siberia. The object entered Earth’s atmosphere traveling at a speed of about 33,500 miles per hour and released the energy equal to 185 Hiroshima bombs. The night skies glowed and the resulting seismic shockwave was registered with sensitive barometers as far away as England. In 1921, Leonid Kulik, the chief curator for the meteorite collection of the St. Petersburg museum led an expedition to Tunguska, but failed in the attempt to reach the area of the blast. Later, in 1927, a new expedition, again led by Kulik, discovered the huge area of leveled forest that marked the place of the Tunguska “meteorite” fall. At the time, Kulik mistook shallow depressions called thermokarst holes for many meteorites craters. However, he didn’t find remnants of the meteorite, and continued to explore the area until World War II. In the early 1930s, British astronomer Francis Whipple suggested that the Tunguska Event was caused by the core of a small comet, while Vladimir Vernadsky, suggested the cause was a lump of cosmic matter. (Rubtsov, 2009). More than a century later the cause of the Tunguska Event remains a mystery.

AmazingStories1927-09

The cover of “The Colour Out of Space” by Frank R. Paul, Amazing Stories, September 1927.

The enigmatic nature of the Tunguska Event inspired several fictional works. In the novel “Extinction Event”, a spin-off book for the science fiction series Primeval, the Tunguska event opened a gargantuan anomaly that periodically opens every few decades. The anomaly is linked to the late Cretaceous, just before the Cretaceous–Paleogene extinction event. The Tunguska Event was also included in two episodes of The X-Files (“Tunguska” and “Terma”). The show suggested that the incident was caused by an asteroid impact. In the plot, Fox Mulder and Alex Krycek traveled to the site of the impact, and discovered a military installation where Russian scientists study the black oil found inside the rock, which contained a microbial form of alien life capable of possessing a human body. In the episode “Piper Maru”, the same alien organism infected Krycek.

After 107 years, the Tunguska Event is still a mystery. Recently it was suggested that the Lake Cheko, a 300-m-wide lake situated a few kilometres from the assumed epicentre of the 1908 Tunguska event, is an impact crater, but several lines of observational evidence contradict the hypothesis.

 

References:

Lovecraft, Howard P. (1927). “The Colour Out of Space”.

Joshi, S. T. (2001). A dreamer and a visionary: H.P. Lovecraft in his time. Liverpool University Press, 302.

Rubtsov, V. (2009): The Tunguska Mystery. Springer-Publisher: 318

 

Annie Montague Alexander, Naturalist and Fossil Hunter.

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Annie Montague Alexander (Image: Gateway Science Museum)

Annie Montague Alexander was born on December 29, 1867, in Honolulu, Hawaii. She was the oldest daughter of Samuel Thomas Alexander and Martha Cooke. Both of her parents were the children of missionaries from New England who had come to the Hawaiian Archipelago in 1832. Her father pioneered in the raising of sugar cane on Maui, and founder of Alexander & Baldwin, Inc., one of the biggest companies in Hawaii.

Annie was educated at home by a governess until age fourteen, when she attended Punahou School in Honolulu for one year. In 1882, she moved with her family to Oakland, California. In the fall of 1887, she attended the Lasell Seminary for Young Women, a junior college in Auburndale, Massachusetts. At Lasell, she would join a close childhood friend from Maui, Mary Beckwith. During the two years she spent there she not enrolled in any science classes but studied nineteenth-century history, political economy, civil government, German, French, logic, dress cutting, and photography. Shortly after, she started to study painting in Paris. Unfortunately she began to suffer severe headaches after long hours at the easel and was warned of the possibility of blindness. Later, she enrolled in a training program for prospective nurses at a local hospital, but dropped after a short time and travelled to Europe with her family. In 1899 she met Martha Beckwith, the younger sister of her childhood friend,Mary Beckwith. They became great friends and both went on a trip to explore Oregon and California. Martha, a graduate of Mount Holyoke College, encouraged Annie to broaden her knowledge of the natural world. A year later, she started attending lectures at the University of California, becoming particularly interested in lectures on paleontology given by Dr. John C. Merriam. That was the beginning of the long relationship between Annie Montague Alexander and the University of California at Berkeley, a relationship that would prove exceptionally advantageous to both of them.

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Annie Montague Alexander during a field trip to Nevada, 1905. (Image: University of California Museum of Paleontology, Berkeley)

At first, Annie limited her involvement to funding several of Merriam’s fossil hunting expeditions, but by the summer of 1901, Annie joined her instructor Dr. Merriam and Vance C. Osmont, an assistant professor of mineralogy at the University of California in a field trip to Shasta County, California. Then she financed and led her own expedition to the Fossil Lake region of southern Oregon. She and her group recovered over 100 fossils from a variety of extinct mammals, including miniature horses and camels. In a letter to Martha she wrote: “The fever for amassing these strange treasures might make of me a collector of the most greedy type, unmoved by ‘threats of Hell or hopes of Paradise.’”

The following summer, Annie financed and organized a new fossil collecting expedition to Shasta County in northern California.  She uncover three important ichthyosaur skeletons, including one nearly complete and exceptionally well-preserved specimen. After examining the skeleton, Merriam concluded that it was a new species of ichthyosaur, which he named Shastasaurus alexandrae in Annie’s honor. She organized a second field trip to Shasta County. Once again, she made an extraordinary discovery: a new genus of ichthyosaur. The fossil was named Thalattosaurus alexandrae as a tribute to Annie.

In 1904, she embarked with her father to a long safari to Africa. Her beloved father died during trip. To recover from her loss, Annie turned to the paleontological fieldwork. She later declared: “It is strange how absorbing this work is. We forget the outside world”.

Annie Montague Alexander on a 1923 expedition in France.

Annie Montague Alexander on a 1923 expedition in France. (Image: Alexander & Baldwin, Inc.)

In the fall of 1905, Annie met C. Hart Merriam chief of the United States Biological Survey. Then she financed a paleontological expedition to the West Humboldt Range in Nevada, to explore the Triassic limestones of the region. This trip, know as the  “Saurian Expedition,” was a great success. Under the leadership of Professor John C. Merriam, the group discovered twenty-five specimens of ichthyosaurs, including some of the largest in the world and the most complete ever found in North America. Annie, later wrote an account of the expedition, illustrated with her own photographs. During that time she met Joseph Grinnell, a young naturalist from Pasadena, California. Grinnell told her of the need for a natural history museum on the west coast. She became enthusiastic with the project and she insisted that the museum should be housed at the University of California. She and Joseph Grinnell would have complete control of the museum and its employees. The cost of the Museum of Vertebrate Zoology was covered almost entirely by Annie. A year later she helped to funding the Department of Paleontology and in 1921 she established the university’s Museum of Paleontology.

Annie’s last extended trip was in the winter of 1947—48 to Baja California, when she and her longtime companion Louise Kellogg  spent three months collecting more than forty-six hundred botanical specimens.

Annie Alexander died, on September 10, 1950, at the age of eighty-two. Her ashes were buried in Makawao Cemetery, Maui. Her contributions were recognized by zoologists and botanists, who named two mammals, two birds, six fossils, and two plants after her.

References:

Barbara R. Stein, “On Her Own Terms. Annie Montague Alexander and the Rise of Science in the American West”. University of California Press, Berkeley, 2001
Rianna M. Williams, “Annie Montague Alexander: Explorer, Naturalist, Philanthropist”. Hawaiian Journal of History, volume 28, 1994.

A Brief Introduction to The Hell Creek Formation.

Hell Creek e Fort Union contact, as seen at Mountain Goat Lake Butte, southwestern North Dakota (Adapted from Fastovsky and Bercovici, 2015)

Hell Creek- Fort Union contact, as seen at Mountain Goat Lake Butte, southwestern North Dakota (Adapted from Fastovsky and Bercovici, 2015)

The Hell Creek Formation (HCF), in the northern Great Plains of the United States, is the most studied source for understanding the changes in the terrestrial biota across the Cretaceous-Paleogene boundary, because preserves an extraordinary record comprised of fossil flora, vertebrates, invertebrates, microfossils, a range of trace fossils, and critical geochemical markers such as multiple iridium anomalies associated with the Chicxulub impact event. The HCF is a fine-grained, fluvially derived, siliciclastic unit, that occupies part of the western Williston Basin, and overlies the Fox Hills Formation (Clemens and Hartman, 2014).
The history of research focused on the Hell Creek Formation and its biota started in October 1901, when William T. Hornaday, director of the New York Zoological Society, travelled to northeastern Montana and discovered three fragments of the nasal horn of a Triceratops in the valley of Hell Creek. He showed the fossils to Henry Fairfield Osborn who decided to include the valley of Hell Creek on the list of areas to be prospected by Barnum Brown the following year.
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Barnum Brown working in a quarry in 1902.

In July 1902, B. Brown arrived to Hell Creek. His field crew included Dr. Richard Swann Lull, and Phillip Brooks. Brown recounted that after their arrival, he found the partial skeleton that would become the type specimen of Tyrannosaurus rex. In 1904, William H. Utterback, preparator and collector for the Carnegie Museum of Natural History, collected a fragment of a jaw of Tyrannosaurus and two skulls of Triceratops. In the summer of 1906, B. Brown returned to Montana, and a year later he published a complete manuscript about the valley of Hell Creek. The field expeditions of 1908 and 1909 were crowned by the discovery of another skeleton of T-rex. Between 1902 and 1910, Osborn, Brown, and Lull published the analysis of some of the fossil vertebrates discovered in the Hell Creek Formation, including Tyrannosaurus rex, Triceratops, and Ankylosaurus.
Micrograph of Wodehouseia spinata and a specimenBisonia niemi, from the upper part of the Hell Creek Formation (Adapted from Fastovsky and Bercovici, 2015).

Micrograph of Wodehouseia spinata and a specimen Bisonia niemi, from the upper part of the Hell Creek Formation (Adapted from Fastovsky and Bercovici, 2015).

Plants are represented by fossil leaves, seeds and cones. Fossil wood is also commonly found in the HCF as permineralized fragments. The Hell Creek macroflora is largely dominated by angiosperms including palms, associated with several ferns, conifers, and single species of cycads and Ginkgo. The study of pollen and spores has played a very important role in the identification of the K/Pg boundary in the HCF. Palynologists were the first scientists to recognize that a major, abrupt change occurred at the end of the Cretaceous. Unlike the Permian-Triassic and Triassic-Jurassic boundaries, the palynologically defined K/Pg boundary is based on the extinction of Cretaceous taxa rather than the appearance of Paleocene taxa. Intimately associated with the K/Pg boundary globally, is the so-called “fern spike”, occurring exclusively at localities where the iridium anomaly is present. (Fastovsky and Bercovici, 2015; Vajda & Bercovici, 2014.)

 

References:

Fastovsky, D. E., & Bercovici, A., The Hell Creek Formation and its contribution to the CretaceousePaleogene extinction: A short primer, Cretaceous Research (2015), http://dx.doi.org/10.1016/j.cretres.2015.07.007
Clemens, W. A., Jr., & Hartman, J. H. (2014). From Tyrannosaurus rex to asteroid impact: early studies (1901- 1980) of the Hell Creek Formation in its type area. In J. Hartman, K. R. Johnson, & D. J. Nichols (Eds.), Geological society of America special paper: 361. The Hell Creek Formation and the Cretaceous-tertiary boundary in the northern great plains (pp. 217-245).
Husson, D., Galbrun, B., Laskar, J., Hinnov, L. A., Thibault, N., Gardin, S., & Locklair, R. E. (2011). “Astronomical calibration of the Maastrichtian (late Cretaceous)”. Earth and Planetary Science Letters 305 (3): 328–340.doi:10.1016/j.epsl.2011.03.008
Johnson, K. R., Nichols, D. J., & Hartman, J. H. (2002). Hell Creek Formation: A 2001 synthesis. The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the northern Great Plains: Geological Society of America Special Paper, 361, 503-510.