E-Mail to Client About Second Set of Sources

Below is a copy of the e-mail I sent to my client which included the sources I found in my second search:

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Hello,

I read your e-mail carefully and preformed several additional searches. From what you told me, articles involving volcanic activities, or molecular decomposition information may be of further interest to you. Some articles mention both biological and geological information, but you want to focus on geology. However, I chose not to discard any and all sources that mentioned biology. Instead I tried to choose articles that mentioned biology but with a focus on geological activities, consequences, and implications.

Below are the citations and abstracts from several articles I found. They are also attached to this e-mail as PDFs.

I hope these sources are more helpful,

Christine Otto

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Sources Chosen from Second Search

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Yin, Hongfu. & Feng, Qinglai. “The Protracted Permo-Triassic Crisis and Multi-Episode Extinction Around the Permian-Triassic Boundary.” Global and Planetary Change. 55.1-3 (2007): 1-20.

Abstract:

The Permo-Triassic crisis was a major turning point in geological history. Following the end-Guadalupian extinction phase, the Palaeozoic biota underwent a steady decline through the Lopingian (Late Permian), resulting in their decimation at the level that is adopted as the Permian-Triassic boundary (PTB). This trend coincided with the greatest Phanerozoic regression. The extinction at the end of the Guadalupian and that marking the end of the Permian are therefore related. The subsequent recovery of the biota occupied the whole of the Early Triassic. Several phases of perturbations in delta 13Ccarb occurred through a similar period, from the late Wuchiapingian to the end of the Early Triassic. Therefore, the Permian-Triassic crisis was protracted, and spanned Late Permian and Early Triassic time. The extinction associated with the PTB occurred in two episodes, the main act with a prelude and the epilogue. The prelude commenced prior to beds 25 and 26 at Meishan and coincided with the end-Permian regression. The main act itself happened in beds 25 and 26 at Meishan. The epilogue occurred in the late Griesbachian and coincided with the second volcanogenic layer (bed 28) at Meishan. The temporal distribution of these episodes constrains the interpretation of mechanisms responsible for the greatest Phanerozoic mass extinction, particularly the significance of a postulated bolide impact that to our view may have occurred about 50,000Myr after the prelude. The prolonged and multi-phase nature of the Permo-Triassic crisis favours the mechanisms of the Earth's intrinsic evolution rather than extraterrestrial catastrophe. The most significant regression in the Phanerozoic, the palaeomagnetic disturbance of the Permo-Triassic Mixed Superchron, widespread extensive volcanism, and other events, may all be related, through deep-seated processes that occurred during the integration of Pangea. These combined processes could be responsible for the profound changes in marine, terrestrial and atmospheric environments that resulted

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Xu, L. & Lin, Y. Platinum-Group Elements of the Meishan Permian-Triassic Boundary Section: Evidence for Flood Basaltic Volcanism. Chemical Geology. 246.1-2 (2007): 55-64.

Abstract:

Permian-Triassic boundary sections record the most severe mass extinction event in geological history. However, there is a long-standing controversy of whether bolide impact and/or basaltic flood volcanism triggered the mass extinction. Platinum-group elements (PGEs) are enriched in most extraterrestrial materials, but highly depleted in the terrestrial crust materials. We analyzed Ir, Ru, Rh, Pt and Pd in a set of samples from the global stratotype section and point (GSSP) of the Permian-Triassic boundary at Meishan, China, using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) and nickel sulfide fire assay (NiS-FA) combined with Te coprecipitation. The samples have no Ir anomaly (5-53 pg/g), and their PGE patterns normalized to chondrites are highly fractionated with Ir/Pd ratios of 0.02-0.03xCI, distinct from most extraterrestrial materials. In contrast, these patterns are closely parallel to those of the Siberian and probably Emeishan flood basalts, suggestive of possible sources of PGEs from the basalts. The abundances of PGEs increase in order of the pyrite lamina on the top of bed 24, bed 25 and bed 26, and then decrease to bed 28, probably indicative of a maximum eruption of the flood basalts during deposition of bed 26. The new data favor massive volcanism, rather than extraterrestrial impact, as a major cause of the Permian-Triassic boundary mass extinction.

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Payne, J. L. & Kump, L. R. “Evidence for Recurrent Early Triassic Massice Volcanism from Quantative Interpretation of Carbon Isotope Fluctuations.” Earth and Planetary Science Letters. 256.1-2 (2007): 264-277.

Abstract:

Carbon cycle disturbance associated with mass extinction at the end of the Permian Period continued through the Early Triassic, an interval of approximately 5 million years. Coincidence of carbon cycle stabilization with accelerated Middle Triassic biotic recovery suggests a link between carbon cycling and biodiversity, but the cause of Early Triassic carbon isotope excursions remains poorly understood. Previous modeling studies have focused exclusively on the initial negative excursion in delta super(1) super(3)C across the Permian-Triassic boundary and have not addressed the cycles of positive and negative excursions observed through the Early Triassic. This study uses a simple carbon cycle box model to investigate potential causes underlying the series of Early Triassic carbon isotope excursions and to assess possible relationships between isotope excursions and coeval patterns of carbonate deposition. According to the model, introduction of carbon with the isotope composition of volcanic CO sub(2) produces small negative carbon isotope excursions followed by larger and more protracted positive excursions. Positive excursions result because increased pCO sub(2) causes warming, enhancing marine anoxia and associated regeneration of phosphate and thus allowing greater productivity. In addition, carbonate weathering is more sensitive than organic carbon weathering to changes in atmospheric pCO sub(2) and climate, causing an increase in the overall delta super(1) super(3)C composition of weathered carbon. Therefore, the full Early Triassic record of negative and positive carbon isotope excursions can only be accounted for within the model by several pulses of carbon release characterized by varying mixtures of organic and mantle isotope compositions. Thermal metamorphism of coal and carbonate rocks in the crust of the Siberian craton during eruption of the Siberian Traps flood basalts provides the most plausible mechanism for such a carbon release scenario. If multiple episodes of CO sub(2) release account for Early Triassic carbon cycle instability (regardless of their precise trigger), then cessation of CO sub(2) release is likely to explain acceleration of biotic recovery early in the Middle Triassic.

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Kaiho, K. & Chen, X. Q. “Close-Up of the End-Permian Mass Extinction Horizon Recorded in the Meishan Section, South China: Sedimentary, Elemental, and Biotic Characterization and a Negative Shift of Sulfate Sulfur Isotope Ratio.” Palaeogeography, Palaeocilmatology, Palaeoecology. 239.3-4 (2006): 396-405.

Abstract:

The Permian/Triassic (P/Tr) boundary beds of the Meishan section, South China, have been re-studied in detail based on complete samples across the P/Tr transition. Under the microscope, the end-Permian mass extinction horizon is calibrated to a 12-mm stratal interval, the top being 19 mm below the top of Bed 24e of the Changhsing Formation. This abrupt disappearance of skeletal fragments of major benthos characterizes the end-Permian extinction event, suggesting a catastrophic event. An abrupt decrease in the super(3) super(4)S/ super(3) super(2)S ratios of seawater sulfate is confirmed to coincide with the end-Permian event horizon. The sulfur isotope event is thought to have been caused by an overturn of a stratified ocean dominated by H sub(2)S, implying coincidence of the oceanic mixing and the mass extinction. Coincident Siberian flood volcanism may have triggered a long-term (>10 super(3) years) cooling leading an ocean mixing. A presumed comet impact to the ocean could have directly caused ocean mixing and the mass extinction.

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Jianzin, Yu. & Yuangiao, Peng. “Terrestrial Events Across the Permian-Triassic Boundary Along the Yunnan-GUizhou Border, SW China.” Global and Planetary Change. 55.1-3 (2007): 193-208.

Abstract:

The border area between western Guizhou and eastern Yunnan Provinces in SW China is an ideal place to undertake research considering the terrestrial-ecological system evolution across the Permian-Triassic boundary (PTB). The study of plant and palynomorph fossils, clay minerals, inorganic geochemistry and sedimentary facies in this area enable us to interpret the events occurring at that time. The extinction pattern of the flora interpreted from megafloral and palynomorph data is demonstrated by a sudden decline of species numbers at the PTB after a long-term of gradual changes, followed by a delayed extinction in the basal Triassic. The two boundary claybeds (Beds 66 and 68 in the Chahe Section, beds 47 and 49 in the Zhejue Section) are considered to be volcanogenic. The inorganic geochemical anomalies occurred between Beds 63 and 69, Chahe Section and Beds 45 and 50, Zhejue Section. Sedimentary facies changed from channels of braided rivers, into flood plains of braided rivers, then to shallow lakes, reflecting a gradual transgression by lakes across the area. Our conclusions are that the mass extinction across the PTB in western Guizhou and eastern Yunnan was probably caused by the Siberian basaltic eruption episode and the siliceous volcanism in South China. These lithospheric events represented by volcanisms heralded a series of climatic and environmental events, giving rise to a catastrophe for the biosphere.

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E-mail to Client About Initial Sources

Below is a copy of the e-mail I sent to my client which included the sources I found in my initial search:

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Hello,

Below this message are the citations and abstracts of a few articles I believe will be useful to you. I have attached each article to this e-mail as a PDF, they are named as follows: last name of author _article title, to make it easy to figure out which is which. Please provide me with some feedback and anything you feel would help clarify your information needs, if they have changed, etc. In addition, all of these articles have been peer-reviewed.

While many of the articles did not mention the meteor impact they did mention falling ash and many scientists determined this could also have been caused by volcanic activities instead of astrological. A lot of this information came from South China. And, as expected, there was much discussion about environmental changes. One article I found interesting was about the hypothesis of a 'global carbon cycle'. I hope this is what you are looking for, if not please clarify. For instance, if any of the articles here are or aren't what your looking for, please be sure to tell me why.


Thank you,

Christine Otto

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Thoughts on My Initial Search

For my inital search I have found 5 articles that I will be sending to my client. I used both Google Scholar and Rutgers Library of Online Databases in my search. Both were useful to me in different ways.

I mostly used Google Scholar to find the titles of supporting articles, but then went to Rutgers Library Online to search the databases for the article since my client requested I proved them with not only the citations but entire articles as well. Google Scholar helped because it allowed me to find articles from multiple databases at Rutgers.

I found that when I excluded the words meteor theory or meteorite the results mostly had to do with volcanic activities. There were also a lot of articles about oceanography and the geology of the ocean floor layers. I even found a few interesting articles about the hypothesis about how the earth goes through 'global carbon cycles'.

I will be typing up an e-mail to send to my Client, including a few articles and asking them to read at least the abstracts and get back to me soon about the relevance of the materials found.

Sampling of Sources From Initial Search

Below are a few sources I found from my initial search. I've included their citation information and abstracts, and they are all peer-reviewed articles.

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Berner, Robert A. “Examination of hypotheses for the Permo-Triassic boundary extinction by carbon cycle modeling.” Proceedings of the National Academy of Sciences of the United States of America. 99.7 (2002); 4172-4177.

Abstract:

The biological extinction that occurred at the Permian-Triassic boundary represents the most extensive loss of species of any known event of the past 550 million years. There have been a wide variety of explanations offered for this extinction. In the present paper, a number of the more popular recent hypotheses are evaluated in terms of predictions that they make, or that they imply, concerning the global carbon cycle. For this purpose, a mass balance model is used that calculates atmospheric CO sub(2) and oceanic delta super(13)C as a function of time. Hypotheses considered include: (i) the release of massive amounts of CO sub(2) from the ocean to the atmosphere resulting in mass poisoning; (ii) the release of large amounts of CO sub(2) from volcanic degassing; (iii) the release of methane stored in methane hydrates; (iv) the decomposition and oxidation of dead organisms to CO sub(2) after sudden mass mortality, and (v) the long-term reorganization of the global carbon cycle. The modeling indicates that measured short-term changes in delta super(13)C at the boundary are best explained by methane release with mass mortality and volcanic degassing contributing in secondary roles. None of the processes result in excessively high levels of atmospheric CO sub(2) if they occurred on time scales of more than about 1,000 years. The idea of poisoning by high levels of atmospheric CO sub(2) depends on the absence of subthermocline calcium carbonate deposition during the latest Permian. The most far-reaching effect was found to be reorganization of the carbon cycle with major sedimentary burial of organic matter shifting from the land to the sea, resulting in less burial overall, decreased atmospheric O sub(2), and higher atmospheric CO sub(2) for the entire Triassic Period.

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Isozaki, Y. & Shimizu, N. “End-Permian extinction and volcanism-induced environmental stress: The Permian-Triassic Boundary interval of lower-slope facies at Chaotian, South China.” Palaeogeography, Palaeoclimatology, Palaeoecology. 252.1-2 (2007); 218-238.

Abstract:

In order to reveal environmental changes across the Permo-Triassic boundary (PTB), the detailed lithostratigraphy of the PTB interval is analyzed at Chaotian in northern Sichuan, China. The studied section is composed of the Changhsingian (Upper Permian) Dalong Formation and the Induan (Lower Triassic) Feixianguan Formation of a lower-slope facies deposited on the northwestern margin of the Yangtze carbonate platform. The 12-m-thick interval across the PTB consists mainly of bedded carbonates and mudstone, and is lithologically divided into 7 units, i.e., Units A to G, in ascending order. The main extinction horizon of Permian taxa is recognized at the Unit D/E boundary where various fossil metazoans and protists, such as ammonoids, brachiopods, bivalves, conodonts, and radiolarians, rapidly disappeared or became scarce. The complete disappearance of radiolarians at the Unit D/E boundary emphasizes that the PTB extinction affected not only various Late Permian benthic and free-swimming metazoans but also planktonic protozoans. The lowest Induan index conodont Hindeodus parvus first occurs at the base of Unit F, marking the biostratigraphically defined PTB horizon. Unit E composed of unique bedded marl between the main extinction horizon and the first occurrence of Triassic taxon represents a period of strong environmental stresses that suppressed productivity both of silica- and carbonate-secreting organisms. By changing their size, radiolarians reacted most sensitively to the environmental change that already started in the late Changhsingian, appreciably before the final extinction event. The frequent intercalation of rhyo-dacitic tuff beds, particularly in Unit D and the lower part of Unit E across the main extinction horizon, suggests that intermittent felsic volcanism and relevant environmental change may have been responsible for the mass extinction of the Permian taxa and for the prolonged post-extinction lag time before the initial recovery. The frequent ash falls during the late Changhsingian indicate that the volcanism-induced environmental change had already started earlier than the main extinction. All the biological production (carbonate, silica, and organic matter) collapsed at the Unit D/E boundary when the environmental stresses may have passed a critical threshold for maintaining ecological stability. The PTB interval between the extinction and the first appearance of Triassic taxon at Chaotian is ca. 1.4 m thick, apparently almost eight times thicker than that at the Global Stratotype Section and Point of PTB in Meishan (19 cm). The Chaotian section, as well as the neighboring Shangsi section in northern Sichuan, may provide a better chance for high-resolution chemostratigraphic analyses that may allow detection and correlation of subtle environmental changes across the PTB.

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Kidder, D. L. & Worsley, T. R. “Causes and consequences of extreme Permo-Triassic warming to globally equable climate and relation to the Permo-Triassic extinction and recovery.” Palaeogeography, Palaeoclimatology, Palaeoecology. 203.3-4 (2004); 207-237.

Abstract:

Permian waning of the low-latitude Alleghenian/Variscan/Hercynian orogenesis led to a long collisional orogeny gap that cut down the availability of chemically weatherable fresh silicate rock resulting in a high-CO2 atmosphere and global warming. The correspondingly reduced delivery of nutrients to the biosphere caused further increases in CO2 and warming. Melting of polar ice curtailed sinking of O2- and nutrient-rich cold brines while pole-to-equator thermal gradients weakened. Wind shear and associated wind-driven upwelling lessened, further diminishing productivity and carbon burial. As the Earth warmed, dry climates expanded to mid-latitudes, causing latitudinal expansion of the Ferrel circulation cell at the expense of the polar cell. Increased coastal evaporation generated O2- and nutrient-deficient warm saline bottom water (WSBW) and delivered it to a weakly circulating deep ocean. Warm, deep currents delivered ever more heat to high latitudes until polar sinking of cold water was replaced by upwelling WSBW. With the loss of polar sinking, the ocean was rapidly filled with WSBW that became increasingly anoxic and finally euxinic by the end of the Permian. Rapid incursion of WSBW could have produced similar to 20 m of thermal expansion of the oceans, generating the well-documented marine transgression that flooded embayments in dry, hot Pangaean mid-latitudes. The flooding further increased WSBW production and anoxia, and brought that anoxic water onto the shelves. Release of CO2 from the Siberian traps and methane from clathrates below the warming ocean bottom sharply enhanced the already strong greenhouse. Increasingly frequent and powerful cyclonic storms mined upwelling high-latitude heat and released it to the atmosphere. That heat, trapped by overlying clouds of its own making, suggests complete breakdown of the dry polar cell. Resulting rapid and intense polar warming caused or contributed to extinction of the remaining latest Permian coal forests that could not migrate any farther poleward because of light limitations. Loss of water stored by the forests led to aquifer drainage, adding another similar to 5 m to the transgression. Non-peat-forming vegetation survived at the newly moist poles. Climate feedback from the coal-forest extinction further intensified warmth, contributing to delayed biotic recovery that generally did not begin until mid-Triassic, but appears to have resumed first at high latitudes late in the Early Triassic. Current quantitative models fail to generate high-latitude warmth and so do not produce the chain of events we outline in this paper. Future quantitative modeling addressing factors such as polar cloudiness, increased poleward heat transport by deep water and its upwelling by cyclonic storms, and sustainable mid-latitude sinking of warm brines to promote anoxia, warming, and thermal expansion of deep water may more closely simulate conditions indicated by geological and paleontological data.

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Knoll, A.H. & Bambach, R.K. “Paleophysiology and end-Permian mass Extinction.” Earth and Planetary Science Letters. 256.3-4 (2007); 295-313.

Abstract:

Physiological research aimed at understanding current global change provides a basis for evaluating selective survivorship associated with Permo-Triassic mass extinction. Comparative physiology links paleontological and paleoenvironmental observations, supporting the hypothesis that an end-Permian trigger, most likely Siberian Trap volcanism, touched off a set of physically-linked perturbations that acted synergistically to disrupt the metabolisms of latest Permian organisms. Global warming, anoxia, and toxic sulfide probably all contributed to end-Permian mass mortality, but hypercapnia (physiological effects of elevated P sub(C) sub(O) sub(2)) best accounts for the selective survival of marine invertebrates. Paleophysiological perspectives further suggest that persistent or recurring hypercapnia/global warmth also played a principal role in delayed Triassic recovery. More generally, physiology provides an important way of paleobiological knowing in the age of Earth system science.

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Xie, Shucheng. & Pancost, Richard. “Molecular and isotopic evidence for episodic environmental change across the Permo/Triasic Boundary at Meishan in South China.” Global and Planetary Change. 55.1-3 (2007); 56-65.

Abstract:

Lipid biomarker abundances and delta 13C values were determined across the Permian-Triassic (P-Tr) boundary at Meishan of southern China. The delta 13C values of n-alkanes showed large (9) fluctuations, which suggest major episodic changes in oceanographic conditions during faunal mass extinctions. Environment-related biomarker ratios, including pristane to phytane ratios (Pr/Ph), gammacerane to C31 homohopane ratios ( gamma /C31HP) and C27 18 alpha (H)-22,29,30-trinorneohopane to C27 17 alpha (H)-22,29,30-trinorhopane ratios (Ts/Tm), vary extensively throughout the section, with values typically associated with anoxic conditions coinciding with maximum delta 13C values. In particular, both faunal mass extinction horizons (beds 25 and 28) are characterised by biomarker ratios consistent with anoxic conditions and elevated n-alkane delta 13C values. The records of environment-related biomarkers and n-alkane delta 13C values clearly signify multiple environmental perturbations in association with faunal mass extinctions.

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