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LIP record
This database
was originally intended to catalogue extensive mafic igneous events and
to evaluate the possible relationship of these events to mantle plumes.
We offer it here as a preliminary listing of LIPs, regardless of origin.
Apart from a few minor corrections, the database is from Table 1 in R.E.
Ernst and K.L. Buchan (2001), "Large mafic magmatic events through
time and links to mantle plume-heads" (chapter 19 in "Mantle
Plumes: Their Identification Through Time", Geological Society of
America Special Paper 352, edited by R.E. Ernst and K.L. Buchan).
Significant advances have been made to the geology of many regions since
this database was published. We are currently working on revisions that
will incorporate these advances.
We are also working
to correct some of the formatting problems (e.g., special characters lost,
dashes replaced by commas) that resulted when the database was translated
into HTML, and to make the database more web friendly. In the interim,
zipped Microsoft EXCEL and ACCESS versions are available in the download
section.
Explanatory
notes
Event:
Type of event listed as “(C)”, continental flood basalt, or
“(O)”, oceanic flood basalt.
Location: Location is given both by country and, in parentheses,
by geologic domain. The location of the center of the plume head is
given for some entries based on the convergence of giant radiating dike
swarms (Ernst et al. 1996; Ernst and Buchan 1997a).
Area: Estimates of the areal distribution of each event have
large uncertainties and are generally minimum estimates. The areal contribution
from dikes is based on the length multiplied by the width of the swarm.
For some events, the volume of magma has also been estimated.
Age: Summary age (in Ga) is based on the detailed dating information
presented elsewhere in the entry. Dating methods are coded as follows:
A = Ar-Ar, K = K-Ar, R = Rb-Sr, S = Sm-Nd, U = U-Pb, P = Pb-Pb, M =
paleomagnetism, G = geological correlations, b = baddeleyite, p = plagioclase,
r= rutile, t = titanite, and z = zircon. Note that the U-Pb category
includes ID-TIMS (isotope dilution, thermal ionization mass spectrometry),
SIMS (secondary ionization mass spectrometry, e.g. SHIRMP, sensitive
high resolution ion microprobe) and zircon lead evaporation (207Pb/206Pb)
ages. There is variation in the uncertainty level associated with published
ages. In general, most published U-Pb uncertainties are given at the
2 sigma level, while most K-Ar, Rb-Sr and Ar-Ar uncertainties are given
at the 1sigma level. However, some recent Ar-Ar uncertainties are presented
at the 2 sigma level. The reader is encouraged to consult the original
paper for the uncertainty level and other details of any particular
age in this table.
Rating: Events are rated in terms of the likelihood of involvement
of a mantle plume head. Ratings are presented in the form Rating (Key
Criteria), e.g. A (1v, 3), B (5), C (9vi). Events are rated as A, B
and C, where A= confidently linked, B= probably linked, and C= possibly
linked – to a mantle plume head. The key criteria used for the
rating are summarized according to the following scheme (which is discussed
further in the text). Criteria 1-3 apply to an ‘A’ rating,
criteria 4-7 to a ‘B’ rating, and 8-10 to a ‘C’
rating.
1
= mafic magmatism > 100 000 sq. km. (or >100 000 cu. km.) and
short duration (<10 m.y.). The key types of magmatic units used
for this estimate are coded as follows: v= volcanic rocks (mainly
flood basalt sequence or its erosional or deformational remnant),
s= mafic sill province, i = layered mafic-ultramafic intrusion province,
and d = mafic dike swarm.
2 = linkage to present-day hotspot.
3 = giant radiating dike swarm.
4 = mafic magmatism > 100 000 sq. km. (or >100 000 cu. km.)
but poorly dated or >20 000 sq. km. (or >20 000 cu. km.) and
of short duration. The key unit types, v, s, i, and d, are explained
in criteria 1.
5 = giant dike swarm (>300 km in length).
6 = “flood-basalt” or “plume” chemistry according
to the cited reference.
7 = komatiites in greenstone belts or picrites in flood basalts.
8 = rift-related (these often show bimodal volcanism).
9 = >20 000 sq. km. (or >20 000 cu. km.) but poorly dated. The
key unit types, v, s, i and d, are explained in criteria 1.
10 = separate centers of magmatic activity linked to a cluster of
small shallow-sourced plume-heads, but a link with single deep-sourced
plume-head is not demonstrated.
References:
Selected references are cited as bracketed numbers. Click here
for the key to the references and here
for the full citations. Click here
to download the entire reference list in .RTF format.
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