SUMMARY / RELATED TOPICS

Deccan Traps

The Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India. They are one of the largest volcanic features on Earth, they consist of multiple layers of solidified flood basalt that together are more than 2,000 m thick, cover an area of c. 500,000 km2, have a volume of c. 1,000,000 km3. The Deccan Traps may have covered c. 1,500,000 km2, with a correspondingly larger original volume. The term "trap" has been used in geology since 1785–1795 for such rock formations, it is derived from the Dutch word for stairs and refers to the step-like hills forming the landscape of the region. The Deccan Traps began forming 66.25 million years ago, at the end of the Cretaceous period. The bulk of the volcanic eruption occurred at the Western Ghats some 66 million years ago; this series of eruptions may have lasted fewer than 30,000 years. The original area covered by the lava flows is estimated to have been as large as 1.5 million km2 half the size of modern India. The Deccan Traps region was reduced to its current size by plate tectonics.

The release of volcanic gases sulfur dioxide, during the formation of the traps contributed to climate change. Data points to an average drop in temperature of about 2 °C in this period; because of its magnitude, scientists have speculated that the gases released during the formation of the Deccan Traps played a major role in the Cretaceous–Paleogene extinction event. It has been theorized that sudden cooling due to sulfurous volcanic gases released by the formation of the traps and toxic gas emissions may have contributed to the K–Pg, as well as other, mass extinctions. However, the current consensus among the scientific community is that the extinction was triggered by the Chicxulub impact event in North America, which would have produced a sunlight-blocking dust cloud that killed much of the plant life and reduced global temperature. Work published in 2014 by geologist Gerta Keller and others on the timing of the Deccan volcanism suggests the extinction may have been caused by both the volcanism and the impact event.

This was followed by a similar study in 2015, both of which consider the hypothesis that the impact exacerbated or induced the Deccan volcanism, since the events occur at antipodes. However, the impact theory is still the best supported and has been determined by various reviews to be the consensus view. Within the Deccan Traps at least 95% of the lavas are tholeiitic basalts. Other rock types present include: alkali basalt, nephelinite and carbonatite. Mantle xenoliths have been elsewhere in the western Deccan; the Deccan Traps are famous for the beds of fossils. Well known species include the frog Oxyglossus pusillus of the Eocene of India and the toothed frog Indobatrachus, an early lineage of modern frogs, now placed in the Australian family Myobatrachidae; the Infratrappean Beds and Intertrappean Beds contain fossil freshwater molluscs. It is postulated; the area of long-term eruption, known as the Réunion hotspot, is suspected of both causing the Deccan Traps eruption and opening the rift that once separated the Seychelles plateau from India.

Seafloor spreading at the boundary between the Indian and African Plates subsequently pushed India north over the plume, which now lies under Réunion island in the Indian Ocean, southwest of India. The mantle plume model has, been challenged. Data continues to emerge that support the plume model; the motion of the Indian tectonic plate and the eruptive history of the Deccan traps show strong correlations. Based on data from marine magnetic profiles, a pulse of unusually rapid plate motion began at the same time as the first pulse of Deccan flood basalts, dated at 67 million years ago; the spreading rate increased and reached a maximum at the same time as the peak basaltic eruptions. The spreading rate dropped off, with the decrease occurring around 63 million years ago, by which time the main phase of Deccan volcanism ended; this correlation is seen as driven by plume dynamics. The motions of the Indian and African plates have been shown to be coupled, the common element being the position of these plates relative to the location of the Réunion plume head.

The onset of accelerated motion of India coincides with a large slowing of the rate of counterclockwise rotation of Africa. The close correlations between the plate motions suggest that they were both driven by the force of the Réunion plume. There is some evidence to link the Deccan Traps eruption to the contemporaneous asteroid impact that created the nearly antipodal Chicxulub crater in the Mexican state of Yucatán. Although the Deccan Traps began erupting well before the impact, argon-argon dating suggests that the impact may have caused an increase in permeability that allowed magma to reach the surface and produced the most voluminous flows, accounting for around 70% of the volume; the combination of the asteroid impact and the resulting increase in eruptive volume may have been responsible for the mass extinctions that occurred at the time that separates the Cretaceous and Paleogene periods, known as the K–Pg boundary. A more recent discovery appears to demonstrate the scope of the destruction from the impact alone, however.

In a March 2019 article in the Proceedings of the N

Renée Van Halm

Renée Van Halm is a Canadian contemporary visual artist born in Haarlemmermeer, the Netherlands and immigrated to Canada in 1953. Renée Van Halm has been featured in over 30 solo exhibitions including numerous exhibitions at the S. L. Simpson Gallery and Birch Contemporary in Toronto, Ontario, as well as Equinox Gallery in Vancouver, British Columbia, Canada. Notable exhibitions include: Interior Projections at Mercer Union, Toronto, ON Voor Gerrit/Healing at University of Lethbridge, AB Songs of Experience at the National Gallery of Canada, Ottawa, ON L’ eau à la bouche, Art Gallery of Greater Victoria, Victoria, BC Anonymous Volumes, Oakville Galleries, Oakville, ON Dream Home, at the Contemporary Art Gallery, BC, Southern Alberta Art Gallery, Lethbridge, AB, Kamloops Art Gallery, Kamloops, BC Reverse Engineering at the S. L. Simpson Gallery and Birch Contemporary in Toronto, ON Cross-Cutting/Inside Out, a 35-year survey exhibition of her works on paper at the Burnaby Art Gallery, Burnaby, BC Shape of Things at the West Vancouver Museum, Vancouver, BC Her work has been included in numerous group exhibitions such as Aurora Borealis at the Centre international d'art contemporain, Montréal, weak thought at the Vancouver Art Gallery, Architypes at the Charles H. Scott Gallery and the Embassy of Canada, Tokyo and Paste at the Equinox Gallery, The Poetics of Space at the Vancouver Art Gallery, New Monuments Forget the Future at Birch Contemporary, Return of the Image at the Beaverbrook Art Gallery, Fredericton, NB, Form Follows Fiction at UTAC, Elusive Utopias at the Judith and Norman Alix Gallery, Sarnia, ON.

Renée Van Halm has a long-standing interest in the history of painting and the production of hybrid objects that blur the space between painting and architecture. She is invested the material processes of painting and the traditional terms of its construction. Of her artistic practice, Van Halm has written: "Cultural history and how we represent and inhabit architecture are fundamental to my work. Over the years I have looked at many subjects that reflect on art and design practices through the genres of still life and landscape as well as decor and pattern. I am drawn to the expectations. Over thirty year ago I began to work with the architecture found in early Renaissance painting, from which I built life sized three-dimensional structures; this work led me to consider. This continues in my current work where I work with images culled from mainstream fashion and decor magazines which I manipulate and juxtapose in new compositions; these form the basis of paintings. My ongoing interests are in how we as individuals and negotiate our private experiences in thespaces where we live."Van Halm incorporates art historical, painterly references, as well as allusions to architectural history.

Art critic Robin Laurence writes: "Her art takes on presence and absence and public, intimacy and grandeur, pre-modernism, postmodernism, all in a manner, gorgeously painterly and rigorously critical. The sources of Van Halm’s imagery range from early Renaissance paintings to contemporary real-estate ads, from interior design publications to her own photographs and collages." Van Halm's work is held in numerous public and private collections including the Art Gallery of Nova Scotia, Halifax. 2002 - Taste/100 painting of the 20th century, Keesee Office Building, now Kirkpatrick Bank, Oklahoma City, OK, USA 2010 - South Hill neighbourhood banner and mural project, Vancouver, BC 2015 - Awarded Joyce-Collingwood Skytrain Station public art commission, TransLink, Vancouver, BC 2016 - Façade Festival, Burrard Arts Foundation, Vancouver Art Gallery Vancouver, BC reneevanhalm.com

Oedignatha

Oedignatha is a genus of Asian spiders first described by Tamerlan Thorell in 1881 as a genus of corrinid sac spiders, moved to Liocranidae in 2014. As of April 2019 it contains thirty-seven species in Southeast Asia, several of which were transferred from other genera, including O. aleipata from Storena, O. andamanensis & O. raigadensis from Amaurobius, O. proboscidea from Corinna, O. ferox from the former monotypic genus Aepygnatha. Oedignatha affinis Simon, 1897 – Sri Lanka Oedignatha albofasciata Strand, 1907 – India Oedignatha aleipata – Samoa Oedignatha andamanensis – India Oedignatha barbata Deeleman-Reinhold, 2001 – Thailand Oedignatha bicolor Simon, 1896 – Sri Lanka Oedignatha binoyii Reddy & Patel, 1993 – India Oedignatha bucculenta Thorell, 1897 – Myanmar Oedignatha canaca Berland, 1938 – Vanuatu Oedignatha carli Reimoser, 1934 – India Oedignatha coriacea Simon, 1897 – Sri Lanka Oedignatha dentifera Reimoser, 1934 – India Oedignatha escheri Reimoser, 1934 – India Oedignatha ferox – Myanmar Oedignatha flavipes Simon, 1897 – Sri Lanka Oedignatha gulosa Simon, 1897 – Sri Lanka Oedignatha indica Reddy & Patel, 1993 – India Oedignatha jocquei Deeleman-Reinhold, 2001 – Thailand Oedignatha lesserti Reimoser, 1934 – India Oedignatha major Simon, 1896 – Sri Lanka Oedignatha microscutata Reimoser, 1934 – India Oedignatha mogamoga Marples, 1955 – Seychelles, Indonesia.

Introduced to Samoa Oedignatha montigena Simon, 1897 – Sri Lanka Oedignatha platnicki Song & Zhu, 1998 – China, Taiwan Oedignatha poonaensis Majumder & Tikader, 1991 – India Oedignatha proboscidea – Sri Lanka Oedignatha procerula Simon, 1897 – India Oedignatha raigadensis Bastawade, 2006 – India Oedignatha retusa Simon, 1897 – Sri Lanka Oedignatha rugulosa Thorell, 1897 – Myanmar Oedignatha scrobiculata Thorell, 1881 – Seychelles, India, Malaysia, Indonesia, Taiwan Oedignatha shillongensis Biswas & Majumder, 1995 – India Oedignatha sima Simon, 1886 – Thailand Oedignatha spadix Deeleman-Reinhold, 2001 – Indonesia Oedignatha striata Simon, 1897 – Sri Lanka Oedignatha tricuspidata Reimoser, 1934 – India Oedignatha uncata Reimoser, 1934 – India