Ludlow (geology)
| system | series | step | ≈ age ( mya ) |
|---|---|---|---|
| higher | higher | higher | younger |
| Silurian | Pridolium | 419.2 ⬍ 423 |
|
| Ludlow | Ludfordium | 423 ⬍ 425.6 |
|
| Gorstium | 425.6 ⬍ 427.4 |
||
| Wenlock | Homerium | 427.4 ⬍ 430.5 |
|
| Sheinwoodium | 430.5 ⬍ 433.4 |
||
| Llandovery | Telychium | 433.4 ⬍ 438.5 |
|
| Aeronium | 438.5 ⬍ 440.8 |
||
| Rhuddanium | 440.8 ⬍ 443.4 |
||
| deeper | deeper | deeper | older |
The Ludlow (rarely also Ludlowium or Ludlovium ) is a chronostratigraphic series in the history of the earth within the Silurian . It began geochronologically about 427.4 million years ago and ended about 423 million years ago. The Ludlow is preceded by the Wenlock series; it is followed by the Pridolium series.
Naming and history
The Ludlow is named after the town of Ludlow in Shropshire ( England ), in the nearby rocks of this age at the surface are pending . Roderick Murchison introduced the term to literature in 1833. Originally, the Ludlow was ranked one level in the hierarchy before getting series rank in 1989.
Definition and GSSP
The Ludlow begins with the base of the Gorstium , which is defined by the (local) onset of the Acritarchen species Leptobrachion longhopense . This boundary is likely also near the base of the Neodiversograptus nilssoni graptolite zone. The boundary to the Pridolium, on the other hand, is clearly defined by the first appearance of the graptolite species Monograptus parultimus . The official reference profile (GSSP = "Global Stratotype Section and Point") for the Gorstium is in the abandoned quarry "Pitch Coppice", approximately 4.5 km southwest of Ludlow on the south side of the road from Ludlow to Wigmore .
Breakdown
The Ludlow series of the Silurian is divided into two geological tiers:
-
System : Silurian (443.4–419.2 mya )
- Series : Pridolium (423–419.2 mya) (not subdivided into further stages)
- Series: Ludlow (427.4–423 mya)
- Level : Ludfordium (425.6–423 mya)
- Level: Gorstium (427.4–425.6 mya)
- Series: Wenlock (433.4–427.4 mya)
- Series: Llandovery (443.4-433.4 mya)
literature
- Felix Gradstein, Jim Ogg & Alan Smith: A Geologic timescale. Cambridge University Press 2004 ISBN 978-0-521-78673-7
- J. Kríz: 1989. The Přídoli Series in the Prague Basin (Barrandium area, Bohemia). In: Holland, CH and Bassett, MG (Eds.). A global standard for the Silurian System. National Museum of Wales, Geological Series, 9: 90-100, Cardiff ZDB -ID & key = zdb 995874-5 .
- JD Lawson and DE White: The Ludlow Series in the Ludlow Area. In: CH Holland and MG Bassett (eds.): A global standard for the Silurian System. National Museum of Wales, Geological Series. 9: 73-90, Cardiff 1989 ZDB -ID & key = zdb 995874-5 .
Web links
- International Chronostratigraphic Chart 2012 (PDF)
- German Stratigraphic Commission, Manfred Menning (Hrsg.): Stratigraphische Tisch von Deutschland 2002 . Potsdam 2002, ISBN 3-00-010197-7 (1 sheet, Stratigraphie.de [PDF; 6.6 MB ]).
- Commission for the paleontological and stratigraphic research of Austria of the Austrian Academy of Sciences (Ed.): The Stratigraphic Table of Austria (sedimentary layer sequences). Vienna 2004 PDF (large)