Home Multi-Country Search About Admin Login
Cenozoic
Mesozoic
Late Paleozoic
Early Paleozoic
Neoproterozoic

Search by
Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple
Nong Son Formation
Click to display on map of the Ancient World at:
Nong Son Fm base reconstruction

Nong Son Fm

Period: 
Triassic

Age Interval: 
Norian-Rhaetian (21)


Province: 
Middle Trung Bo

Type Locality and Naming

Nong Son Depression; Western Quang Nam Province.

Synonym: Nong Song Gr. Considered as the Nong Song Group with a lower An Diem Fm of Norian continental red beds and an upper Suon Giua Fm of Rhaetian coal-bearing beds by Tong-Dzuy Thanh and Vu Khuc (2011), but retained as a unified Nong Gong Fm by Tran Van Tri and Vu Khuc (2011; used here). - Séríe de Nong-son: Bourret R. 1925 (Ret). - Loạt Nông Sơn: Cát Nguyên Hùng et aì. (in Tống Duy Thanh et aỉ.) 1995. - Điệp Nông Sơn: Nguyễn Chí lỉường 1983; Vũ Khúc 1990, (in Vũ Khúc et aỉ.) 1984, (in Vũ Khúc, Bùi Phú Mỹ et al.) 1990. - Diệp Nông Sơn (part.): Hoàng Đình Khâm 1977. - Hệ tầng Nông Sơn: Nguyễn Văn Trang eí ai. 1995.


Lithology and Thickness

Chacteristic section along the road from Thanh My to Ngoe King areas with 1060 m in thickness, composed of two parts: (1) 410 m of coarse-grained continental red beds, composed of polymictic conglomerate, reddish sandstone, breccias and gritstone. (2) 650 m of coal-bearing beds including sandstone interbbeded with dark-grey siltstone and shale with industrial coal seams in the uppermost part (thickest reaches up to 30 m).


Lithology Pattern: 
Sandstone


Relationships and Distribution

Lower contact

Rests unconformably upon Paleozoic quartz-mica schist or marble. Regionally, the next younger unit is the rhyolite of the Middle Triassic Mang Yang Fm.

Upper contact

Unconformably overlain by the Tho Lam Fm.

Regional extent

Restricted to adjacent areas of the Nong Song and Ngoc Kinh Coal Mines and around the Suon Giua Mt (Quang Nam Province).


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[107.65,15.93],[108,15.86],[108.43,15.9],[108.64,15.67],[108.43,15.6],[107.55,15.61],[107.38,15.67],[107.39,15.85],[107.64,15.93],[107.65,15.93]]]]}}

Fossils

Coal shale in upper unit yields fossils of the Hon Gai Flora, with 83 species, including Sphenozamites marioni, Podozamites rarinervis, Palissya brauni, Cladophlebis ngockinensis, and Goeppertella vietnamica.


Age 

Norian-Rhaetian age on the basis of these fossils and general correlation with other Triassic coal-bearing formations.

Age Span: 

    Beginning stage: 
Norian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
227.30

    Ending stage: 
Rhaetian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
201.36

Depositional setting

Continental red beds (Norian) to Rhaetian coal-bearing beds


Depositional pattern:  

Additional Information


Compiler:  

Tran Van Tri and Vu Khuc (Editors; Geology and Earth Resources of Viet Nam, General Dept. of Geology and Minerals of Viet Nam; completed in Dec., 2011), with additional details from Tong-Dzuy Thanh and Vu Khuc (Editors; Stratigraphic Units of Viet Nam, 2nd edition; 2011; English edited by A. Boucot).