Earth's middle age

Peter A. Cawood, Chris J. Hawkesworth

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Earth's middle age, extending from 1.7 to 0.75 Ga, was characterized by environmental, evolutionary, and lithospheric stability that contrasts with the dramatic changes in preceding and succeeding eras. The period is marked by a paucity of preserved passive margins, an absence of a signifi cant Sr anomaly in the paleoseawater record and in the εHf(t) in detrital zircon, a lack of orogenic gold and volcanichosted massive sulfi de deposits, and an absence of glacial deposits and iron formations. In contrast, anorthosites and kindred bodies are well developed and major pulses of Mo and Cu mineralization, including the world's largest examples of these deposits, are features of this period. These trends are attributed to a relatively stable continental assemblage that was initiated during assembly of the Nuna supercontinent by ca. 1.7 Ga and continued until breakup of its closely related successor, Rodinia, ca. 0.75 Ga. The overall low abundance of passive margins is consistent with a stable continental confi guration, which also provided a framework for environmental and evolutionary stability. A series of convergent margin accretionary orogens developed along the edge of the supercontinent. Abundant anorthosites and related rocks developed inboard of the plate margin. Their temporal distribution appears to link with the secular cooling of the mantle, at which time the overlying continental lithosphere was strong enough to be thickened and to support the emplacement of large plutons into the crust, yet the underlying mantle was still warm enough to result in widespread melting of the lower thickened crust.

Original languageEnglish
Pages (from-to)503-506
Number of pages4
JournalGeology
Volume42
Issue number6
DOIs
Publication statusPublished - 2014
Externally publishedYes

Keywords

  • Zircon
  • Crustal growth
  • Hadean

Cite this

Cawood, P. A., & Hawkesworth, C. J. (2014). Earth's middle age. Geology, 42(6), 503-506. https://doi.org/10.1130/G35402.1
Cawood, Peter A. ; Hawkesworth, Chris J. / Earth's middle age. In: Geology. 2014 ; Vol. 42, No. 6. pp. 503-506.
@article{59504f33b3e64e9d933cdb81fd0d7ed6,
title = "Earth's middle age",
abstract = "Earth's middle age, extending from 1.7 to 0.75 Ga, was characterized by environmental, evolutionary, and lithospheric stability that contrasts with the dramatic changes in preceding and succeeding eras. The period is marked by a paucity of preserved passive margins, an absence of a signifi cant Sr anomaly in the paleoseawater record and in the εHf(t) in detrital zircon, a lack of orogenic gold and volcanichosted massive sulfi de deposits, and an absence of glacial deposits and iron formations. In contrast, anorthosites and kindred bodies are well developed and major pulses of Mo and Cu mineralization, including the world's largest examples of these deposits, are features of this period. These trends are attributed to a relatively stable continental assemblage that was initiated during assembly of the Nuna supercontinent by ca. 1.7 Ga and continued until breakup of its closely related successor, Rodinia, ca. 0.75 Ga. The overall low abundance of passive margins is consistent with a stable continental confi guration, which also provided a framework for environmental and evolutionary stability. A series of convergent margin accretionary orogens developed along the edge of the supercontinent. Abundant anorthosites and related rocks developed inboard of the plate margin. Their temporal distribution appears to link with the secular cooling of the mantle, at which time the overlying continental lithosphere was strong enough to be thickened and to support the emplacement of large plutons into the crust, yet the underlying mantle was still warm enough to result in widespread melting of the lower thickened crust.",
keywords = "Zircon, Crustal growth, Hadean",
author = "Cawood, {Peter A.} and Hawkesworth, {Chris J.}",
year = "2014",
doi = "10.1130/G35402.1",
language = "English",
volume = "42",
pages = "503--506",
journal = "Geology",
issn = "0091-7613",
publisher = "Geological Society of America",
number = "6",

}

Cawood, PA & Hawkesworth, CJ 2014, 'Earth's middle age', Geology, vol. 42, no. 6, pp. 503-506. https://doi.org/10.1130/G35402.1

Earth's middle age. / Cawood, Peter A.; Hawkesworth, Chris J.

In: Geology, Vol. 42, No. 6, 2014, p. 503-506.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Earth's middle age

AU - Cawood, Peter A.

AU - Hawkesworth, Chris J.

PY - 2014

Y1 - 2014

N2 - Earth's middle age, extending from 1.7 to 0.75 Ga, was characterized by environmental, evolutionary, and lithospheric stability that contrasts with the dramatic changes in preceding and succeeding eras. The period is marked by a paucity of preserved passive margins, an absence of a signifi cant Sr anomaly in the paleoseawater record and in the εHf(t) in detrital zircon, a lack of orogenic gold and volcanichosted massive sulfi de deposits, and an absence of glacial deposits and iron formations. In contrast, anorthosites and kindred bodies are well developed and major pulses of Mo and Cu mineralization, including the world's largest examples of these deposits, are features of this period. These trends are attributed to a relatively stable continental assemblage that was initiated during assembly of the Nuna supercontinent by ca. 1.7 Ga and continued until breakup of its closely related successor, Rodinia, ca. 0.75 Ga. The overall low abundance of passive margins is consistent with a stable continental confi guration, which also provided a framework for environmental and evolutionary stability. A series of convergent margin accretionary orogens developed along the edge of the supercontinent. Abundant anorthosites and related rocks developed inboard of the plate margin. Their temporal distribution appears to link with the secular cooling of the mantle, at which time the overlying continental lithosphere was strong enough to be thickened and to support the emplacement of large plutons into the crust, yet the underlying mantle was still warm enough to result in widespread melting of the lower thickened crust.

AB - Earth's middle age, extending from 1.7 to 0.75 Ga, was characterized by environmental, evolutionary, and lithospheric stability that contrasts with the dramatic changes in preceding and succeeding eras. The period is marked by a paucity of preserved passive margins, an absence of a signifi cant Sr anomaly in the paleoseawater record and in the εHf(t) in detrital zircon, a lack of orogenic gold and volcanichosted massive sulfi de deposits, and an absence of glacial deposits and iron formations. In contrast, anorthosites and kindred bodies are well developed and major pulses of Mo and Cu mineralization, including the world's largest examples of these deposits, are features of this period. These trends are attributed to a relatively stable continental assemblage that was initiated during assembly of the Nuna supercontinent by ca. 1.7 Ga and continued until breakup of its closely related successor, Rodinia, ca. 0.75 Ga. The overall low abundance of passive margins is consistent with a stable continental confi guration, which also provided a framework for environmental and evolutionary stability. A series of convergent margin accretionary orogens developed along the edge of the supercontinent. Abundant anorthosites and related rocks developed inboard of the plate margin. Their temporal distribution appears to link with the secular cooling of the mantle, at which time the overlying continental lithosphere was strong enough to be thickened and to support the emplacement of large plutons into the crust, yet the underlying mantle was still warm enough to result in widespread melting of the lower thickened crust.

KW - Zircon

KW - Crustal growth

KW - Hadean

UR - http://www.scopus.com/inward/record.url?scp=84902122156&partnerID=8YFLogxK

U2 - 10.1130/G35402.1

DO - 10.1130/G35402.1

M3 - Article

VL - 42

SP - 503

EP - 506

JO - Geology

JF - Geology

SN - 0091-7613

IS - 6

ER -