Publication Date:
2017-10-20
Description:
In the arid environment, due to the scarcity
of a continuous terrestrial archive, lacustrine
sequences are often employed as a paleoenvironmental
repository. However, numerous spatial and temporal
heterogeneities exist concerning previously studied
sites in arid central Asia. Furthermore, surveys using a
XRF core scanning technique on lacustrine sequences
retrieved in hyperarid desert settings are largely rare.
Hence, two parallel sediment cores (ONW I; ONW II)
were retrieved from Orog Nuur, in the Gobi Desert of
Mongolia. Continuous, high-resolution elemental
abundances at a 1-cm scanning step size were
examined in core ONW II using XRF core scanning.
To constrain the data quality, elements with high error
margins relative to measured peak areas and those
elements/proxies below the significance level during
the multivariate statistics are excluded for environmental/
provenance implications. Based on multivariate
statistical evaluation, the bulk-geochemistry of the
core sediments are governed by (1) grain-size composition,
(2) authigenic productivity (Ca, Cl, CaCO3)
in an alkaline environment, (3) allochthonous organic
material (TOC and C/Natomic), and (4) terrigenous
input via fluvial inflows, as well as quasi-constant
aeolian input through the late Quaternary (Al, Si, K,
Ti, and Fe). Disparate source lithotypes, as well as
authigenic productivity of the lake system existed
before and after Termination I. The Holocene was
dominated by a distinct high productivity alkaline
environment with more felsic and alkaline input
relative to the late Pleistocene. This might be
attributed to an increased hydrodynamic strength of
riverine inflow and/or intensified erosion and weathering
of felsic source rocks in the upper catchment of
the Orog Nuur. Therefore, in order to gain a better
understanding of the bulk-geochemistry of lake sediments,
the coupled provenance and environmental
signatures, as well as land surface processes in the
catchment need to be systematically discerned. Thus,
the XRF core scanning data obtained in this study
would have practical and complimentary merit for
other lacustrine studies focused on the desert realm
across the globe.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
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