Vol. 200 No. 3 (1978): Meddelelser om Grønland
I. Introduction. s. 5
General. s. 5.
Geological setting. s. 5 Topography in the area east of Marmorilik. s. 7
Mapping and topographic base. s. 7
II. Stratigraphy. s. 7
Procedure followed in establishing the stratigraphy. s. 7
Summary of the stratigraphy of the Marmorilik Formation. s. 10
Basement and the basal unconformity. s. 11
The basal Quartzite-Semipelite Member. s. 12
At type section 1. s. 12
South of the 480 m lake. s. 13
West of the 746 m lake. s. 13
Petrography in the Quartzite-Semipelite Member. s. 14
The Lower Dolomite Member. s. 15
At type section 1. s. 15
West of the 470 m lake. s. 16
At type section 2 (south-east of the 480 m lake). s. 16
Between the 480 and 746 m lakes. s. 16
Petrography in the Lower Dolomite Member. s. 17
The Thin Calcite Marble Member. s. 18
The Grey Dolomite Member. s. 19
At type section 2 and between the 480 and 746 m lakes. s. 19
At type section 3 north of the 470 m lake. s. 19
Petrography in the Grey Dolomite Member. s. 19
Inverted sequences and tectonic breccia at type section 3. s. 20
The Banded Marble Member. s, 20
Petrography in the Banded Marble Member. s. 21
The Massive Calcite Marble Member. s. 22
At type section 3. s. 22
North of the 480 m lake. s. 22
Petrography in the Massive Calcite Marble Member. s. 22
The Semipelite Member (Black Angel mountain). s. 25
Petrography in the Semipelite Member. s. 26
The north face of the Black Angel mountain. s. 26
Dolerite Dykes. s. 28
Quaternary deposits. s. 28
III. Metamorphism. s. 28
Introduction; field observations. s. 28
Mineral parageneses. s. 30
Mineral compositions. s. 32
Conditions of metamorphism. s. 32
Timing of metamorphism. s. 35
IV. Structure. s. 35
General structure. s. 35
The large open syncline. s. 35
Faults. s. 36
Recumbent folds and thrusts. s. 36
Open folds and monoclines. s. 40
Structures in restricted areas. s. 40
A tight syncline between the 480 and 746 m lakes. s. 40
Angular folds east of Agfardlikavsâ. s. 41
Structure of the Black Angel mountain. s. 41
Structure of the cliff facing Agfardlikavsâ. s. 41
Structure of the north-west facing cliffs. s. 43
Structural position of the Black Angel. s. 44
Small-scale structures. s. 44
Cross-cutting foliations. s. 44
Linear structures: general orientation. s. 44
Rodding and mineral lineation. s. 46
Tight to isoclinal folds. s,. 48
Tectonic breccia. s. 52
Slip along joints in competent beds. s. 52
Minor structures in the area of the tight syncline. s. 52
Time relationship between various types of structure. s. 53
Common relations of recumbent folds and thrusts. s. 54
Relations between thrusts and the tight syncline. s. 54
Evidence from linear structures. s. 54
Faults: relation to other structures. s. 54
Conclusion. s. 55
V. Mineralisation. s, 55
Introduction. s. 55
Descriptions. s. 55
Low-grade mineralisations. s. 55
Massive mineralisations. s.56
Stratigraphic control of mineralisations. s.58
Metal contents of ordinary marbles. s. 58
Conclusions. s. 59
Analytical procedure. s. 60
VI. Origin of the Marmorilik Formation. s. 60
Regional aspects. s. 60
Some characteristics of the Marmorilik Formation relevant to its origin. s. 60
Distribution of calcite and dolomite marble. s. 61
Massive, weakly banded carbonates with graphite and/or pyrite. s. 61
Absence of stromatolites. s.62
Distribution and possible significance of scapolite. s. 62
Semipelite-banded carbonate rocks, semipelite and related rocks. s.63
Quartz in the Marmorilik Formation. s. 63
Origin of the carbonates in the Marmorilik Formation. s. 64
Primary calcium carbonate. s.64
Conditions of deposition of the carbonates. s.64
a) The role of organisms. s.64
b) Water depth. s. 65
c) Dolomitisation. s. 65
The Marmorilik Formation in the context of Precambrian carbonate formations. s. 66
Acknowledgements. s. 68
References. s.69
