scholarly journals Grain size parameters and sedimentary structures of a last Interglacial marine sand body, near Westport, New Zealand

1968 ◽  
Vol 2 (3) ◽  
pp. 447-471 ◽  
Author(s):  
G. J. Van Der Lingen ◽  
Peter B. Andrews
Keyword(s):  
Grain Size ◽  
New Zealand ◽  
Last Interglacial ◽  
Sedimentary Structures ◽  
Marine Sand ◽  
Sand Body ◽  
Grain Size Parameters

Mineralogical and textural discrimination of loess derived from a tephra near Rotorua, New Zealand

Soil Research ◽  
1988 ◽  
Vol 26 (2) ◽  
pp. 301 ◽  
Author(s):  
LA Benny ◽  
NM Kennedy ◽  
JH Kirkman ◽  
RB Stewart
Keyword(s):  
Grain Size ◽  
New Zealand ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Field Observations ◽  
Mean Grain Size ◽  
Mean Size ◽  
The Mean ◽  
Grain Size Parameters

Grain size parameters and clay mineralogical analyses were used to characterize and compare Okareka Ash and post-Okareka tephric loess sampled at eight sites on a transect in Rotorua district, North Island, New Zealand. Grain size distribution analyses show consistently lower mean size and better sorting of the tephric loess compared with the Okareka Ash. The mean grain size of the loess is strongly influenced by the mean grain size of the tephra. Trends in the distribution of biotite and halloysite support the grain size distribution analyses. Taken with field observations, the analytical evidence allows differentiation between Okareka Ash and overlying associated tephric loess.

Grain-size parameters of marine sediments

Oceanology ◽  
2006 ◽  
Vol 46 (3) ◽  
pp. 430-439
Author(s):  
T. N. Alekseeva ◽  
V. N. Sval’nov
Keyword(s):  
Grain Size ◽  
Marine Sediments ◽  
Grain Size Parameters

A review of New Zealand palaeoclimate from the Last Interglacial to the global Last Glacial Maximum

2015 ◽  
Vol 110 ◽  
pp. 92-106 ◽  
Author(s):  
Paul W. Williams ◽  
Matt McGlone ◽  
Helen Neil ◽  
Jian-Xin Zhao
Keyword(s):  
New Zealand ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Interglacial ◽  
Last Glacial

scholarly journals Facies Evaluation and Depositional Environments of Carbonates of the Bagh Group, Dhar District, Madhya Pradesh, India

2021 ◽  
Vol 38 (1) ◽  
pp. 33-40
Author(s):  
Sreejita Chatterjee ◽  
Dhiren Kumar Ruidas
Keyword(s):  
Grain Size ◽  
Large Scale ◽  
Energy Condition ◽  
Size Variation ◽  
High Energy ◽  
Depositional Environments ◽  
Small Scale ◽  
Peninsular India ◽  
Sedimentary Structures ◽  
Nodular Limestone

A significant event of marine transgression took place in Central India during Late Turonian-Coniacian. Fossiliferous marine succession of Bagh Group is one of the few carbonate successions exposed in peninsular India which was in focus of the current study for understanding this event. The signatures of this event were identified in the carbonate succession. The carbonates of Bagh Group are composed of two formations: the lower part is represented by Nodular limestone Formation which is overlain by Bryozoan limestone Formation at the top. On the basis of grain size variation and sedimentary structures, the Nodular limestone is divisible into three facies: facies ‘A’, facies ‘B’ and facies ‘C’. A hardground exists between facies B and facies C. Lack of sedimentary structures and high mud content indicates low energy depositional setting for the Nodular limestone Formation. Similarly, Bryozoan limestone Formation is divisible into five facies: facies ‘D’, facies ‘E’, facies ‘F’, facies ‘G’ and facies ‘H’ based on grain size variation and sedimentary structures. All of these five facies are fossiliferous. Glauconites are present within facies ‘G’ and have two modes of occurrence - as infilling within Bryozoan limestone and as altered feldspar. Presence of both small- and large-scale cross-stratification in Bryozoan limestone with lesser mud content are indicative of high energy shallow marine conditions. Large-scale cross-stratifications are possibly representing tidal bars while the small scale cross stratifications are formed in inter bar setting. Presence of reactivation surfaces within facies ‘E’ also supports their tidal origin. Increase in depositional energy condition is also evident from dominated by packstone facies.

scholarly journals Actuopaleontological investigations of shallow water Red Sea echinoids

1992 ◽  
Vol 6 ◽  
pp. 220-220
Author(s):  
James H. Nebelsick
Keyword(s):  
Grain Size ◽  
Red Sea ◽  
Distribution Patterns ◽  
Close Correlation ◽  
Time Averaging ◽  
Multivariate Statistical ◽  
Cryptic Habitats ◽  
Echinometra Mathaei ◽  
Grain Size Parameters ◽  
Diadema Setosum

The regular and irregular echinoid fauna of the Northern Bay of Safaga (Red Sea, Egypt) has been investigated within the framework of an actuopaleontological study of the flora, fauna, sediments and facies. The distribution of echinoids has been compared to grain size parameters as well as to the distribution of other organisms.The study area (ca. 10 × 7 km) was investigated using SCUBA-diving techniques along 55 transects with a total length of 126 km. Echinoid presence was quantified using weights of fragments (2 mm) originating from 67 standardized bulk samples distributed throughout the Bay. The complex morphology of the echinoid test and the spines allow the identification of fragmented material upon comparison to complete specimens. The resulting data was analyzed using correlation techniques as well as Q and R-mode multivariate statistical analysis. This method counters the difficulties originating from the cryptic habitats and patchy distributions.The results of the analysis show that echinoid distribution can be analyzed for both regular and irregular wchinoid taxa despite taphonomic bias and restrictions imposed by the analytic method. Time averaging in fact counters the difficulties arising from the patchy distributions of echinoids. There is a close correlation of echinoid distribution to sedimentary and bottom facies as well as to grain size parameters and other environmental factors. The distribution of irregular echinoids is highly differentiated with coarse coastal sand dominated by Clypeaster sp., Echinodiscus auritus, Fibularia ovulum, and Lovenia elongata; muddy sands by Laganum depressum, Clypeaster sp. and Echinocyamus crispus; and muds by members of the Schizasteridae. Regular echinoids, mostly Eucidaris metularia, Echinometra mathaei, Tripneustes gratilla, Heterocentrotus mammillatus and Diadema setosum, dominate the sediments found within, or near reefs, coral carpets and patch reefs.The methodology used in this actuopaleontological investigation should be useful in recognizing the distribution patterns of ancient echinoid faunas, especially in light of the significance of regular echinoids in the bioerosion of reefs and irregular echinoids in the bioturbation of sediments.

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