scholarly journals Revisiting the phosphorite deposit of Fontanarejo (central Spain): new window into the early Cambrian evolution of sponges and the microbial origin of phosphorites

2021 ◽  
pp. 1-20
Author(s):  
Joachim Reitner ◽  
Cui Luo ◽  
Pablo Suarez-Gonzalez ◽  
Jan-Peter Duda
Keyword(s):  
Early Cambrian ◽  
Central Spain ◽  
Exceptional Preservation ◽  
Small Shelly Fossils ◽  
Clastic Sediments ◽  
Rapid Formation ◽  
Phosphorite Deposit ◽  
Geological Map ◽  
Channel Deposits ◽  
First Time

Abstract Fossils within early Cambrian phosphorites worldwide are often well preserved due to early diagenetic permineralization. Here, we examine the fossil record contained within phosphorites of the Lower Cambrian Pusa Formation (late Fortunian to Cambrian Stage 2) in Fontanarejo, central Spain. The sedimentology and age of these phosphorites have been controversial and are here reviewed and discussed, providing also an updated geological map. The Pusa Formation is composed of fine clastic sediments that are partly turbiditic, with channels of quartz-rich conglomerates and abundant phosphorites in the upper part of the succession. The microfacies and mineralogy of these channel deposits are studied here for the first time in detail, showing that they are mainly composed of subspherical apatite clasts, with minor mudstone intraclasts, quartzite and mica grains. Numerous sponge spicules, as well as entirely preserved hexactinellid sponges and demosponges, were collected within these phosphorites and likely represent stem groups. In addition to sponges, other fossils, such as small shelly fossils (SSF) of the mollusc Anabarella sp., were found. The phosphorites exhibit multiple evidence of intense microbial activity, including diverse fabrics (phosphatic oncoidal-like microbialites, thrombolites, stromatolites and cements) and abundant fossils of filamentous microbes that strongly resemble extant sulphur-oxidizing bacteria. Our findings strongly suggest that microbial processes mediated the rapid formation of most of the Fontanarejo apatite, probably accounting for the exceptional preservation of fragile fossils such as sponge skeletons. The apparent presence of taxonomically diverse hexactinellid and demosponge communities at the lowermost Cambrian further corroborates a Precambrian origin of the phylum Porifera.

scholarly journals Revisiting the phosphorite deposit of Fontanarejo (central Spain): new window into the early Cambrian evolution of sponges and into the microbial origin of phosphorites

2020 ◽  
Author(s):  
Joachim Reitner ◽  
Cui Luo ◽  
Pablo Suarez-Gonzales ◽  
Jan-Peter Duda
Keyword(s):  
Early Cambrian ◽  
Central Spain ◽  
Exceptional Preservation ◽  
Small Shelly Fossils ◽  
Clastic Sediments ◽  
Phosphorite Deposit ◽  
Geological Map ◽  
Sulfur Oxidizing ◽  
Channel Deposits ◽  
First Time

Fossils within early Cambrian phosphorites worldwide are often well preserved due to early diagenetic permineralization. Here, we examine the fossil record contained within phosphorites of the Lower Cambrian Pusa Formation (late Fortunian to Cambrian Stage 2) in Fontanarejo, central Spain. The sedimentology and age of these phosphorites have been controversial and are here reviewed and discussed, providing also a updated geological map. The Pusa Formation is composed of fine clastic sediments that are partly turbiditic, with channels of quartz-rich conglomerates and abundant phosphorites in the upper part of the succession. The microfacies and mineralogy of these channel deposits are studied here for the first time in detail, showing that they are mainly composed of subspherical apatite clasts, with minor mudstone intraclasts, quartzite and mica grains. Numerous sponge spicules, as well as entirely preserved hexactinellid sponges and demosponges, were collected within these phosphorites and likely represent stem groups. In addition to sponges, other fossils, such as small shelly fossils (SSF) of the mollusk Anabarella sp., were found. The phosphorites exhibit multiple evidence of intense microbial activity, including diverse fabrics (phosphatic oncoidal-like microbialites, thrombolites, stromatolites, and cements) and abundant fossils of filamentous microbes that strongly resemble sulfur oxidizing bacteria. Our findings strongly suggest that microbial processes mediated the rapid formation of most of the Fontanarejo apatite, probably accounting for the exceptional preservation of fragile fossils such as sponge skeletons. The apparent presence of taxonomically diverse hexactinellid and demosponge communities by the lowermost Cambrian further corroborates a Precambrian origin of the phylum Porifera

scholarly journals Tarimspirafrom the Cambrian (Series 2, Stage 4) of Laurentia (Greenland): extending the skeletal record of paraconodontid vertebrates

2018 ◽  
Vol 93 (1) ◽  
pp. 115-125
Author(s):  
John S. Peel
Keyword(s):  
New Species ◽  
Type Species ◽  
Weak Acid ◽  
Early Cambrian ◽  
Basal Cavity ◽  
Stage 4 ◽  
First Time ◽  
A New Species ◽  
North Greenland

AbstractPhosphatic sclerites of the problematicTarimspiraYue and Gao, 1992 (Cambrian Series 2) recovered by weak acid maceration of limestones display a unique range of mainly strongly coiled morphologies. They were likely organized into multielement scleritomes, but the nature of these is poorly known; some sclerites may have had a grasping function.Tarimspirasclerites grew by basal accretion in an analogous fashion to younger paraconodonts (Cambrian Series 3–4) but lack a basal cavity. Based on proposed homologies,Tarimspiramay provide an extension of the early vertebrate paraconodont–euconodont clade back into the early Cambrian.Tarimspirais described for the first time from Laurentia (North Greenland), extending its known range from China and Siberia in Cambrian Series 2. In addition to the type species,Tarimspira planaYue and Gao, 1992, the Greenland record ofTarimspiraincludes two morphotypes of a new species,Tarimspira artemi.UUID:http://zoobank.org/c7c536c8-cdaf-49a9-ae1d-77c392f553fc.

Latest Early Cambrian small shelly fossils, trilobites, and Hatch Hill dysaerobic interval on the Québec continental slope

2002 ◽  
Vol 76 (2) ◽  
pp. 287-305 ◽  
Author(s):  
Ed Landing ◽  
Gerd Geyer ◽  
Kenneth E. Bartowski
Keyword(s):  
New York ◽  
Sea Level ◽  
Continental Slope ◽  
Sea Level Change ◽  
Early Cambrian ◽  
The West ◽  
Fossil Assemblage ◽  
Level Change ◽  
New Name ◽  
Small Shelly Fossils

Latest Early Cambrian continental slope deposition of the early Hatch Hill dysaerobic interval (new name, latest Early Cambrian—earliest Ordovician) is recorded by dark grey shales and turbidite limestones in the Bacchus slice at Ville Guay, Québec. Platform-derived microfaunas of the Bicella bicensis trilobite assemblage were transported into a dysoxic environment of the upper “Anse Maranda Formation,” and many organisms were buried alive. Phosphatization preserved a diverse skeletal fossil assemblage that includes four agnostid trilobites, echinoderm debris, and twenty small shelly fossil taxa. The latter include five helcionellids; Pelagiella Matthew, 1895b, classified herein as a gastropod; a bivalve (Fordilla Barrande, 1881); the brachiopod Linnarssonia taconica Walcott, 1887; two conodontomorphs; four hyoliths; and such phosphatic and calcareous problematica as Coleoloides Walcott, 1889, emend. Most small shelly fossil taxa, including Discinella micans Billings, 1872, range through much of the Olenellus Zone and Elliptocephala asaphoides assemblage interval. Trilobites allow a more resolved correlation into the uppermost Olenellus Zone. A comparable stratigraphy occurs in Cambrian—Ordovician slope facies of the Bacchus slice and the Giddings Brook slice in eastern New York. The “Anse Maranda Formation” correlates with the West Granville—Browns Pond—lower Hatch Hill formations in eastern New York and brackets two dysaerobic intervals (Browns Pond and early Hatch Hill). Sea-level change associated with the Hawke Bay regression between the Browns Pond and Hatch Hill onlap/dysaerobic intervals led to the longest period of oxygenated green shale and sandstone deposition on the east Laurentian slope in the late Early Cambrian-earliest Ordovician.

PALEOECOLOGIC SIGNIFICANCE OF MALACOFAUNA, OLDUVAI GORGE, TANZANIA

Palaios ◽  
2016 ◽  
Vol 31 (6) ◽  
pp. 319-326 ◽  
Author(s):  
CLAUDIA C. JOHNSON ◽  
JACKSON K. NJAU ◽  
DIRK VAN DAMME ◽  
KATHY SCHICK ◽  
NICHOLAS TOTH
Keyword(s):  
Olduvai Gorge ◽  
Snail Species ◽  
Archaeological Remains ◽  
Intermediate Hosts ◽  
Running Water ◽  
Northern Tanzania ◽  
Environmental Setting ◽  
The Rich ◽  
Channel Deposits ◽  
First Time

Abstract The rich record of vertebrate, hominin and archaeological remains recovered from Olduvai Gorge in northern Tanzania stands in stark contrast to the largely unexplored macroinvertebrate record from the region. Here we examine fossil malacofauna from Olduvai Gorge, inclusive of new discoveries and previous reports, and survey their potential as paleoecologic indicators. Recorded for the first time from Olduvai, an assemblage of fossil bivalve shells is attributed by character comparison to modern Chambardia wahlbergi, a freshwater unionid species widespread across Africa. The fossilized shells were localized in Bed III conglomerate channel deposits, with channel geometry exhibiting scour bases and superimposed fill structures with fining upward sequences. The ecology of recent C. wahlbergi combined with sedimentological data indicate the aquatic environment in this region during Olduvai Bed III times can be reconstructed as a periodically desiccated floodplain bordering a river channel or channels with permanent running water and marked seasonal fluctuations. This paleo-environmental setting presents drastic change compared with that of the lower Bed I and Bed II deposits, when an alkaline/saline lake extended over the site and fresh water was restricted to standing groundwater-fed pools with snail species known today to be intermediate hosts for the trematode genera Schistosoma (schistosomiasis) and Fasciola (fascioliasis). This research enhances details of landscape evolution at Olduvai basin and furthers paleoenvironmental interpretations during the time of Bed III deposition.

Asynchronous trilobite extinctions at the early to middle Cambrian transition

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 441-445 ◽  
Author(s):  
F.A. Sundberg ◽  
K.E. Karlstrom ◽  
G. Geyer ◽  
J.R. Foster ◽  
J.W. Hagadorn ◽  
...  
Keyword(s):  
Critical Time ◽  
Data Sets ◽  
Early Cambrian ◽  
Earth System ◽  
Middle Cambrian ◽  
West Gondwana ◽  
Paleoclimatic Data ◽  
First Time ◽  
Age Constraints ◽  
Prior Models

Abstract Trilobites appeared and diversified rapidly in the Cambrian, but it is debated as to whether their radiations and extinctions were globally synchronous or geographically restricted and diachronous. The end of the early Cambrian is a classic example—it has traditionally been defined by the extinction of olenellid and redlichiid trilobites and the appearance of paradoxidid trilobites. Here we integrate the global biostratigraphy of these three trilobite groups with high-precision tuff and tandem detrital zircon U-Pb age constraints to falsify prior models for global synchronicity of these events. For the first time, we demonstrate that olenellid trilobites in Laurentia went extinct at least 3 Ma after the first appearance of paradoxidids in Avalonia and West Gondwana (ca. 509 Ma). They also disappeared before the extinction of redlichiids and prior to the base of the Miaolingian at ca. 506 Ma in South China. This indicates that these three trilobite groups (paradoxidids, olenellids, and redlichiids) and their associated biotas overlapped in time for nearly 40% of Cambrian Epoch 2, Age 4. Implications of this chronological overlap are: (1) trilobite transitions were progressive and geographically mediated rather than globally synchronous; and (2) paleontological databases underestimate the diversity of the early Cambrian. This ∼3 Ma diachroneity, at a critical time in the early evolution of animals, also impacts chemostratigraphic and paleoclimatic data sets that are tied to trilobite biostratigraphy and that collectively underpin our understanding of the Cambrian Earth system.

William Smith (1769–1839): His struggles as a consultant, in both geology and engineering, to simultaneously earn a living and finance his scientific projects, to 1820.

2016 ◽  
Vol 35 (1) ◽  
pp. 1-46 ◽  
Author(s):  
Hugh Torrens
Keyword(s):  
Early Career ◽  
Water Drainage ◽  
Land Drainage ◽  
Agricultural Community ◽  
Increase Food Production ◽  
Geological Map ◽  
First Time ◽  
Very High ◽  
Considerable Support ◽  
Made In

This paper deals with Smith's, highly complex, early ‘career paths’ to 1820. His first employment was as (1) a land surveyor. Then in 1793 he became both (2) canal surveyor, and (3) engineer, to the Somerset Coal Canal Company (SCCC). These now guaranteed him a regular income. But all suddenly changed, when he was successively dismissed, first as surveyor, then as engineer, in 1799. He had now to find other means of supporting himself, and publicising the important geological discoveries, he had made in Somerset. From the mid 1790s, Smith had there done (4) land drainage and irrigation work, for the chairman of the SCCC, and immediately after these dismissals. Smith was able to generate an adequate living from such West Country work, during a period of very high rainfall. This took him to Tytherton in Wiltshire. Here he first encountered a new rock unit (the Kellaways Rock) and here the Norfolk agriculturalist Thomas Coke was able to study Smith's new skills with water. News of his competence quickly passed throughout an agricultural community, then desperate to increase food production, during a long wartime period of crisis. Smith's methods of water drainage and irrigation work were now widely taken up, first by the Dukes of Manchester and Bedford, in Bedfordshire, and then by Coke and his relatives, both in Staffordshire and Norfolk, and then by Coke's many tenants in Norfolk. On top of this, Smith's skills as an engineer meant he was soon in high demand also as (5) a Sea Breach Engineer, in attempts to keep the German Ocean (now North Sea) out of The Broads. But Napoleonic war time conditions were harsh, and bills often not swiftly paid (or paid at all). So Smith tried new careers either as (6) a failed author, whether on Irrigation, or Norfolk or as (7) a consultant mineral surveyor—the field he had pioneered. Throughout much of this period, Smith's obsessive attempts to publish his geological discoveries, which needed considerable support for such a novel publication, were thwarted, by the bankruptcies of others, and proved futile, until 1815. This paper tries to survey, for a first time, Smith's complex, and fluctuating, financial situations, over the period 1793 to 1819 (when he entered a debtors' prison). His ‘knight in shining armour’ was undoubtedly the cartographer John Cary (1755–1835) who, in 1812, agreed to publish Smith's great ‘geological’ map. Thus only by “the enterprise of [this] private tradesman…, [what] had been in vain expected from princely patronage, and the sanction of national boards” was accomplished.

Sclerophora peronella new to the Iberian Peninsula

2004 ◽  
Vol 36 (3-4) ◽  
pp. 265-267 ◽  
Author(s):  
Guillermo Amo ◽  
Ana Rosa Burgaz
Keyword(s):  
Iberian Peninsula ◽  
Fagus Sylvatica ◽  
Research Group ◽  
Southern Europe ◽  
Central Spain ◽  
Beech Forests ◽  
The Third ◽  
Natural Reserve ◽  
First Time

An interesting calicioid lichen has been collected as a consequence of the study that our research group is developing in the Iberian meridional beech forests. One of these is the forest Natural Reserve “Chaparral de Montejo” (Madrid Province), which represents one of the southern biogeographic limits of Fagus sylvatica in the Iberian Peninsula. The geological substratum is Silurian clayey slate. It is located in the Supramediterranean belt of central Spain. Sclerophora peronella has been found for the first time in the Iberian Peninsula and for the third time in southern Europe. The previous records in S Europe are from Calabria (Italy) by Puntillo (1992) and from Corse (France) by Vězda (Lich. Sel. Exs. 828).

Stable isotope geochemistry and palynology of the late Precambrian to Early Cambrian sequence in Newfoundland

1992 ◽  
Vol 29 (8) ◽  
pp. 1662-1673 ◽  
Author(s):  
Harald Strauss ◽  
Stefan Bengtson ◽  
Paul M. Myrow ◽  
Gonzalo Vidal
Keyword(s):  
Stable Isotope ◽  
Organic Carbon ◽  
Isotope Geochemistry ◽  
Depositional Environments ◽  
Early Cambrian ◽  
Bacterial Sulfate Reduction ◽  
Stable Isotope Geochemistry ◽  
Forming Process ◽  
Late Precambrian ◽  
Clastic Sediments

A sequence of clastic sediments in southeastern Newfoundland straddling the Precambrian–Cambrian boundary has been investigated for its stable isotope geochemistry of carbon and sulfur and acid-resistant organic-walled microfossils. A detailed study of the Chapel Island Formation, which includes the boundary interval, has revealed fluctuations in the isotopic composition of organic carbon. These are largely interpreted as caused by differences in the depositional environments. Highly variable sulfur isotopic compositions indicate bacterial sulfate reduction as a pyrite-forming process, sometimes under sulfate-limited conditions. Palynological results are quite limited with respect to diagnostic microfossils.

Early Cambrian priapulid worms buried with their lined burrows

2006 ◽  
Vol 143 (5) ◽  
pp. 743-748 ◽  
Author(s):  
XI-GUANG ZHANG ◽  
XIAN-GUANG HOU ◽  
JAN BERGSTRÖM
Keyword(s):  
Lower Cambrian ◽  
Southern China ◽  
Early Cambrian ◽  
Exceptional Preservation ◽  
Sediment Layers

Five specimens of the priapulid Maotianshania cylindrica preserved inside their lined burrows were described from the Lower Cambrian Chengjiang deposits near Kunming, southern China. The exceptional preservation suggests that this worm made a dwelling tube by lining within the uppermost sediment layers. This seems to be unique among priapulids in comparison with the Cambrian Selkirkia and Paraselkirkia, as well as some modern priapulid larvae and loriciferans. Taphonomic evidence indicates that the burrow-and-worm specimens are not buried in situ but were moved by storm, tsunami, or turbidity generated currents that are thought to have brought sedimentary material intermittently.

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