Herznach-Member

Rappresentazione e statuto

Colore CMYK

(0%,13%,31%,12%)

Colore RGB

R: 225 G: 195 B: 155

Rango

Membro litostratigrafico (Sotto-formazione)

Uso

Unità in uso.

Status

termine formale valido

SCS nota

FR: de (et non d')

Discussione del statuto

Nomenclatura

Deutsch

Herznach-Member

Français

Membre de Herznach

Italiano

Membro di Herznach

English

Herznach Member

Origine del nome

Stillgelegtes Bergwerk östlich von Herznach (AG), Tafeljura ; siehe auch Eisenweg

Varianti storiche

Anceps-Athleta-Schichten auct., Fer sous-oxfordien auct., oolithische Eisenerze des Oberen Dogger von Herznach = Herznacher Eisenoolith = Eisenoolith von Herznach-Wölflinswil = Fricktaler Eisenoolith (Bühler 1986), Herznach Formation (Gygi 2000b, Gygi 2000c), Herznach-Member (Bitterli 2015)

Descrizione

Descrizione

Nur für den Nordwestschweizer Jura: Eisenoolithischer, grauer bis rotbrauner Kalkmergel bis Mergel, teilweise sehr fossilreich (Ammoniten, Bivalven, Gastropoden, Brachiopoden).

Potenza

Weniger als 10 cm bis max. 5-6 m ; 3,4 m an der Typlokalität (Gygi 2000c), 6,2 m bai Wölflinswil (Fehlmann & Rickenbach 1962 Pl.2)

Componenti

Eisenoolithischer Mergel bis Kalkmergel

• quarzo
• pirite

Detritischer Quarz, Pyrit.

• ammoniti
• spugne
• vertebrati
• coralli
• legno
• gasteropodi
• crinoidi
• nautili
• belemniti
• echinoidi
• bivalvi

Ammoniten, Nautiliden, Belemniten, Bivalven, Gastropoden, Echiniden, Crinoiden, Korallen, Schwämme, Vertebratenreste, Treibholz.

Gerarchia e successione

Unità di rango superiore

• Ifenthal-Formation

Unità di rango inferiore

• Schellenbrücke-Bank
• «Mariae-Schichten»
• Wölflinswil-Eisenoolith
• «Leitschicht»
• «Herznach-Eisenoolith»

Unità sovrastante

• Birmenstorf-Member
• Wildegg-Formation
• Bärschwil-Formation
• Renggeri-Member
• Membre du Graitery

Unità sottostante

• «Dalle nacrée»
• Ängistein-Member
• Unter-Erli-Bank

Limite superiore

Das über der Schellenbrücke-Bank liegende Birmenstorf-Member (Basis der Wildegg-Formation) bildet die obere Grenze des Herznach-Members.

Limite inferiore

Die Unter-Erli-Bank des Ängistein-Members bildet die untere Grenze des Herznach-Members.

Età

Geomorfologia

• Oxfordiano medio

Osservazioni sul tetto

Cordatum-Subzone (diachron ; Gygi & Marchand 1982)

Età alla base

• primo Calloviano

Osservazioni sulla base

Enodatum-Subzone (diachron ; Jeannet 1951)

Metodo di datazione

Biostratigraphie: Ammoniten (Gygi & Marchand 1982, Hostettler 2014).

Geografia

Estensione geografica

Nordwestschweiz, von der Grenze zu Frankreich bis in den östlichen Aargauer Tafeljura und weiter in den Kanton Schaffhausen. Am Rand der Franches Montagnes nur reliktisch erhalten (Hostettler 2014). Fehlt im östlichen Aargauer Jura (Auenstein).

Regione-tipo

Aargauer Tafeljura (AG)

Località-tipo

• Herznach (AG)
  Caratteristiche del sito
  • typische Fazies
  Agibilità del sito
  • unzugängliches Gelände
  • Steinbruch, Tongrube
  Coordinate
  • (2645340 / 1258360)
  Nota
  • ehem. Bergwerk (Jeannet 1951 Fig.2 A5-F3, Gygi 1977 Pl.11 Profil RG209, Gygi 2000b/c, Gygi 2002, Bitterli-Dreher 2012)

Sezione-tipo

• Herznach (AG)
  Caratteristiche del sito
  • typische Fazies
  Agibilità del sito
  • unzugängliches Gelände
  • Steinbruch, Tongrube
  Coordinate
  • (2645340 / 1258360)
  Nota
  • ehem. Bergwerk (Jeannet 1951 Fig.2 A5-F3, Gygi 1977 Pl.11 Profil RG209, Gygi 2000b/c, Gygi 2002, Bitterli-Dreher 2012)
• Bohrung Hübstel (AG)
  Caratteristiche del sito
  • Untergrenze
  • typische Fazies
  Agibilità del sito
  • Bohrkern
  Coordinate
  • (2645289 / 1259031)
  Nota
  • <p>Kernbohrung Hübstel (AG): Bitterli-Dreher 2012 Fig.5</p>

Sezione di riferimento

• Tongrube Andil (BL), Liesberg
  Caratteristiche del sito
  • Obergrenze
  • Untergrenze
  • typische Fazies
  Agibilità del sito
  • Steinbruch, Tongrube
  Coordinate
  • (2598625 / 1250100)
  Nota
  • 1-1,2 m (Gygi 1990, Gründel & Hostettler 2012)
• Weichlen (AG)
  Caratteristiche del sito
  • Obergrenze
  • typische Fazies
  Agibilità del sito
  • Steinbruch, Tongrube
  Coordinate
  • (2645020 / 1258710)
  Nota
  • Grube nordwestlich von Herznach (Bitterli-Dreher 2012)

Paleogeografia e tettonica

• Dogger (Jura)

Paleogeografia

Northern Tethyan Carbonate Platform (Jura > Helv.) :
Plateforme de Bourgogne, ... = Northern Tethyan Carbonate Platform (NTCP)

Termini generici

• Jura :
  Juragebirge

Tipo di origine

• sedimentaria

Condizioni di formazione

seicht/untief sub-marin

Metamorfismo

non metamorfo

Referenze

Definizione

Gygi R. A. (2000) : Integrated stratigraphy of the Oxfordian and Kimmeridgian (Late Jurassic) in northern Switzerland and adjacent southern Germany. Denkschriften der Schweizerischen Akademie der Naturwissenschaften 104, 152 S.

S.51

Revisione

Gygi R. A. (2000) : Annotated index of lithostratigraphic units currently used in the Upper Jurassic of northern Switzerland. Eclogae geol. Helv. 93/1, 125-146

p.133: Herznach Formation (Gygi 2000b) ; Synonymy: Gygi (2000b. p. 51) The name Herznach Formation was proposed by Gygi (2000b p. 51). The type locality is in the galleries of the now closed iron mine near the village of Herznach. Canton Aargau. LK 1069 Frick. The excellent and detailed section published by Jeannet (1951. Fig. 2) can serve as type section even though it is no more accessible. The Herznach Formation begins in this section with bed A5 and ends with bed F3. Bed F3 is the equivalent of bed 8 in section RG 209 in the Herznach iron mine as published by Gygi 1977, Pl. 11, section 1. The Herznach Formation is a succession of iron oolites of varying age and has a thickness of 3.4 m in the old part of the iron mine below Hübstel hill at Herznach. 2.4 m of this thickness are made up by the iron oolitic orebody. The thickness of the orebody increases southwest of Wölflinswil. a village 4 km to the west of Herznach. to 6.2 m (Fehlmann & Rickenbach 1962. PI. 2). The Herznach Formation is therefore a unit which is mappable at the scale of 1:25.000 (see Fehlmann & Rickenbach 1962. PI. 1 The age of the formation is documented with ammonites to be from the latest part of the early Callovian (Enodatum Subchron. Jeannet 1951) to the Cordatum Subchron of the Cordatum Chron (Gygi & Marchand 1982). The Herznach Formation is several meters thick only in the region of Herznach. To the east it pinches out completely at Veltheim. Canton Aargau. in section RG 226 in Mangold & Gygi (1997. Fig. 2) where a thin iron oolite of the middle Bathonian is overlain by the Birmenstorf Member of the Transversarium Chron. middle Oxfordian. Only in Canton Schaffhausen the formation thickens again and there grows to a thickness of more than 2 m (Fehlmann & Rickenbach 1962 Fig. 12). Iron ore of this formation was mined at Blumberg nearby in southern Germany during World War 2. In northwestern Switzerland the formation is usually only a few decimeters thick and forms a marker bed between the Dalle nacrée Member below and the Renggeri Member above. It has been mined for iron at Erzberg east of Schelten Pass in Canton Solothurn (Fehlmann & Rickenbach 1962. p. 44).

Pubblicazioni importanti

Jeannet Alphonse (1951) : Stratigraphie und Paläontologie des oolithischen Eisenerzlagers von Herznach und seiner Umgebung. Beitr. Geol. Schweiz, geotech. Ser. 13/5, 240 Seiten

Jeannet A. (1954) : Die Macrocephaliten des Callovien von Herznach (Aargau). Eclogae geol. Helv. 47/2, 223–268

Fehlmann H., Rickenbach E. (1962) : Die eisenhaltigen Doggererze der Schweiz. Die Eisen- und Manganerze der Schweiz, Vol.7, 109–116

Gygi R., Marchand Didier (1976) : La zone à Lamberti d'Herznach (Suisse). C.R. Acad. Sc. Paris 282

Gygi R., Marchand Didier (1977) : L'Oxfordien inférieur d'Herznach (canton d'Argovie, Suisse). C.R. Acad. Sc. Paris 285

Bühler Rolf (1986) : Bergwerk Herznach: Erinnerungen an den Fricktaler Erzbergbau. AT Verlag Aarau (Stuttgart)

Bitterli-Dreher P. (2012) : Die Ifenthal-Formation im nördlichen Jura. Swiss Bull. angew. Geol. 17/2, 93-117