Water column euxinia and wildfire evidence during deposition of the Upper Famennian Hangenberg event horizon from the Holy Cross Mountains (central Poland)

2007 ◽  
Vol 144 (3) ◽  
pp. 569-595 ◽  
Author(s):  
LESZEK MARYNOWSKI ◽  
PAWEŁ FILIPIAK
Keyword(s):  
Organic Matter ◽  
Event Horizon ◽  
Black Shale ◽  
Rapid Change ◽  
Taxonomic Composition ◽  
Critical Threshold ◽  
Holy Cross Mountains ◽  
Central Poland ◽  
Palynological Study ◽  
Amorphous Organic Matter

A palynological study of the uppermost Famennian section from Kowala Quarry (Holy Cross Mountains, central Poland) allowed recognition of two miospore zones: LV (Retispora lepidophyta–Apiculiretusispora verrucosa) and LN (Retispora lepidophyta–Verrucosisporites nitidus). Based on palynology and sedimentology, the black shale within the upper part of the section is identified as equivalent to the Hangenberg Black Shale, which is known globally. This black shale contains compounds characteristic of photic zone euxinia, including isorenieratane and its derivatives. Such compounds are absent in the organic-poor marls and shales occurring below the LN Zone, and are present only as traces in the layers just above the black shale, indicating fluctuations in the oxygen minimum zone during uppermost Famennian sedimentation. Palynofacies show high amounts of amorphous organic matter and prasinophyte concentrations in the black shale, and a subsequent significant decrease of amorphous organic matter concomitant with a rapid increase of terrestrial input (mainly miospores with common tetrads) in the layers above the black shale. This supports the relatively rapid change in the taxonomic composition of phytoplankton caused by fluctuations of the chemocline. The whole succession corresponds to one sea-level rise and fall. The presence of high concentrations of peri-condensed polycyclic aromatic hydrocarbons and large amounts of small charcoal particles at the Hangenberg event horizon indicate the occurrence of wildfires. Such observations suggest that atmospheric O22 levels had exceeded the critical threshold of 13 %, above which wildfires may occur, by latest Famennian time.

scholarly journals Controls on amorphous organic matter type and sulphurization in a Mississippian black shale

2019 ◽  
Vol 268 ◽  
pp. 1-18 ◽  
Author(s):  
Joseph F. Emmings ◽  
Jan A.I. Hennissen ◽  
Michael H. Stephenson ◽  
Simon W. Poulton ◽  
Christopher H. Vane ◽  
...  
Keyword(s):  
Organic Matter ◽  
Black Shale ◽  
Organic Matter Type ◽  
Amorphous Organic Matter

Geochemical and palynological study of the Upper Famennian Dasberg event horizon from the Holy Cross Mountains (central Poland)

2010 ◽  
Vol 147 (4) ◽  
pp. 527-550 ◽  
Author(s):  
LESZEK MARYNOWSKI ◽  
PAWEŁ FILIPIAK ◽  
MICHAŁ ZATOŃ
Keyword(s):  
Water Column ◽  
Event Horizon ◽  
Large Scale ◽  
Land Plant ◽  
Organic Content ◽  
Significant Rise ◽  
Late Devonian ◽  
Holy Cross Mountains ◽  
Conodont Zonation ◽  
Palynological Study

AbstractIntegrated palynological, organic and inorganic geochemical and petrographical methods have been used for deciphering the depositional redox conditions and character of organic matter of the Famennian Dasberg event horizon from the deep-shelf Kowala succession of the Holy Cross Mountains. The ages of the investigated samples have been established, using miospore data, as VF (Diducites versabilis–Grandispora famenensis) and LV (Retispora lepidophyta–Apiculiretusispora verrucosa) miospore Zones of the Middle/Upper Famennian. In the standard conodont zonation, this corresponds to the uppermost postera to lowermost praesulcata Zones. The presence of green sulphur bacteria biomarkers and dominance of small-sized framboids together with the presence of large framboids and low values of the U/Th ratio may indicate that during sedimentation of the lower Dasberg shale, intermittent anoxia occurred in the water column, or the anoxic conditions prevailed in the upper part of the water column, while the bottom waters were oxygenated, at least briefly. Deposition of the upper Dasberg shale was characterized by both bottom water and water column anoxia. The lack of acritarcha taxa from these intervals could have been due to anoxia in the photic zone. Moreover, organic content is high in those samples. There is no geochemical evidence for anoxia during sedimentation of the deposits sandwiched between the lower and upper Dasberg shales, or in the deposits which underlie and overlie both Dasberg shale horizons. The two discrete anoxic events are interpreted to be the result of major transgressions and the blooming of primary producers. Above the Dasberg shales, small fragments of charcoal and raised concentrations of polycyclic aromatic hydrocarbons are detected. This supports the presence of wildfires during deposition of shales just above the boundary of VF/LV palynological zones. Temperatures calculated from the fusinite reflectance values suggest that the charcoal was formed in low-temperature ground and/or surface fires. The typical marine character of sedimentation combined with the high proportion of charcoals suggests that wildfires were large-scale, and that there was intensive transport of terrestrial material. The main causes of intensive wildfires were a significant rise of O2 in the atmosphere and important progress in the land plant diversity during Late Devonian times. Palynofacies studies suggest that the transgression corresponds to the part IIf of the Late Devonian sea-level curve.

scholarly journals Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO<sub>2</sub> tolerance in phytoplankton productivity

2018 ◽  
Vol 15 (1) ◽  
pp. 209-231 ◽  
Author(s):  
Stacy Deppeler ◽  
Katherina Petrou ◽  
Kai G. Schulz ◽  
Karen Westwood ◽  
Imojen Pearce ◽  
...  
Keyword(s):  
Organic Matter ◽  
Ocean Acidification ◽  
Primary Productivity ◽  
Phytoplankton Community ◽  
Bacterial Abundance ◽  
Critical Threshold ◽  
Bacterial Productivity ◽  
High Co2 ◽  
Chl A ◽  
Antarctic Marine

Abstract. High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343 µatm) to 1641 µatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a) and particulate organic matter (POM) in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140 µatm. CO2 levels  ≥ 1140 µatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C), causing significant reductions in gross primary production (GPP14C), Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C : N ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs) and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments  ≥ 953 µatm (days 3–5), yet gross bacterial production (GBP14C) remained unchanged and cell-specific bacterial productivity (csBP14C) was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON) combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative effects on the Antarctic food web and the biological pump, resulting in negative feedbacks on anthropogenic CO2 uptake. Increases in bacterial abundance under high CO2 conditions may also increase the efficiency of the microbial loop, resulting in increased organic matter remineralisation and further declines in carbon sequestration.

New Devonian microconchids (Tentaculita) from the Holy Cross Mountains, Poland

2011 ◽  
Vol 85 (4) ◽  
pp. 757-769 ◽  
Author(s):  
Michał Zatoń ◽  
Wojciech Krawczyński
Keyword(s):  
Sedimentation Rate ◽  
Distal Portion ◽  
Taxonomic Composition ◽  
Soft Bottom ◽  
Holy Cross Mountains ◽  
Competition For Space ◽  
High Sedimentation ◽  
New Material ◽  
Three New Species ◽  
Hard Substrates

Tentaculitoid microconchid tubeworms from Devonian (uppermost Emsian-upper Givetian) deposits of the Holy Cross Mountains, Poland, include three new species from stratigraphically well-constrained lithological units:Polonoconchus skalensisn. gen. n. sp.,Palaeoconchus sanctacrucensisn. sp. andMicroconchus vinnin. sp. The microconchids inhabited fully marine environments during transgressive pulses, as is evidenced from facies and associated fossils.Polonoconchus skalensisn. gen. n. sp. andPalaeoconchus sanctacrucensisn. sp. inhabited secondary firm- to hard-substrates in deeper-water, soft-bottom environments. They developed planispiral, completely substrate-cemented tubes and planispiral tubes with elevated apertures, which is indicative of environments where sedimentation rate is low but competition for space (by overgrowth) may be high.Microconchus vinnin. sp., on the other hand, developed a helically coiled distal portion of the tube as a response to a high sedimentation rate. As the taxonomic composition of Devonian microconchids is poorly recognized at both regional and global scales, this new material contributes significantly to our understanding of the diversity of these extinct tube-dwelling encrusters.

Sign in / Sign up

Export Citation Format

Share Document